High-Tech Sustainable Beauty: Exploring Nanotechnology for the Development of Cosmetics Using Plant and Animal By-Products

Abstract

In a world increasingly focused on eco-conscious living, the cosmetic industry is actively adopting nanotechnology to transform plant and animal by-products into high-value beauty products. This comprehensive review explores the innovative and sustainable approaches for extracting and utilizing bioactive compounds from these by-products. The application of nanocarrier systems is highlighted for their role in enhancing the delivery efficacy and safety of these ingredients in skincare and beauty products. Consumer demand and environmental concerns drive the shift towards natural and sustainable cosmetic products. Traditional cosmetic production often involves significant ecological impacts, prompting the industry to seek greener alternatives. This review addresses the critical need for sustainable beauty solutions that align with global sustainability goals, particularly those outlined in the 2030 Agenda for Sustainable Development. The review provides valuable insights into current trends and future directions in sustainable cosmetics by focusing on nanotechnology and by-products. The review uniquely integrates nanotechnology with sustainability practices in the cosmetic industry. It details the benefits of using nanocarriers to improve the stability, bioavailability, and efficacy of bioactive compounds derived from natural waste. This intersection of high-tech methodologies and sustainability offers a novel perspective on cosmetic innovation. Future research should focus on overcoming the technical, regulatory, and economic challenges of scaling up nanotechnology applications. Investigations should include the development of transparent supply chains, standardization methods for characterizing nanoparticles, and comprehensive lifecycle assessments to ensure environmental safety. Additionally, fostering collaboration between scientific research, industry practices, and consumer education is vital for advancing sustainable practices. This review contributes to the broader discourse on sustainable beauty by presenting a clear pathway for integrating these innovative approaches. It ensures that future cosmetic products meet consumer expectations for efficacy and safety and promote environmental stewardship and a circular economy, ultimately benefiting both the skin and the planet.

1. Introduction

In recent years, the beauty market has experienced a significant shift towards natural and sustainable cosmetic products, driven by a consumer base that is increasingly vigilant about the ingredients they apply to their skin. This preference shift has spurred innovation within the cosmetic industry, particularly in harnessing plant and animal by-products as valuable resources. Often discarded from various industrial processes, such by-products present substantial environmental challenges and opportunities for economic development within the beauty sector [1].

When not managed properly, these by-products contribute to ecological issues; they emit greenhouse gases such as methane and carbon dioxide as they decompose in landfills, exacerbating climate change and air pollution. Additionally, improper disposal risks contaminating soil and water sources. To mitigate these environmental impacts and align with the trend towards sustainability, the cosmetic industry has begun exploring innovative approaches to convert these by-products into valuable ingredients for beauty products. This alignment is also guided by global initiatives like the 2030 Agenda for Sustainable Development, emphasizing goals such as responsible consumption and production, climate action, and life on land [2].

The process of extracting and purifying valuable molecules from these by-products, however, is fraught with challenges. The yield and quality of the extracted molecules can vary significantly depending on the source material and the extraction methods employed. The purification process must also address impurities and contaminants inherent in the by-products, and the variability in their composition due to seasonal changes complicates the standardization of the final product’s quality [3]. Lifecycle assessment (LCA) is a critical tool in this context, helping to evaluate the environmental impact of cosmetic products from the cradle to the grave, thus identifying areas where sustainable improvements can be made [4].

Despite the challenges associated with processing plant and animal by-products, they can hold substantial economic potential when refined into high-value cosmetics products. These by-products are a rich source of bioactive compounds, which are increasingly sought after in the beauty industry for their diverse and potent properties. For instance, collagen, derived from animal by-products such as bones, skin, and fat, is highly valued for its anti-aging and moisturizing effects. Similarly, plant by-products, including fruit peels, vegetable scraps, and cereal residues, contain a variety of bioactive compounds such as epicatechins, catechins, curcumin, hydroxybenzoic acids, gallic acids, cinnamic acids, quercetin, ascorbic acids, luteolin, alpha and beta carotene, complex polysaccharides, and fatty acids. These compounds are known for their robust antioxidant activities, which combat free radicals and prevent oxidative damage to the skin, thus contributing to anti-aging effects and enhanced skin hydration and elasticity [5,6,7].

Utilizing these compounds in cosmetics leverages their therapeutic properties and promotes a sustainable approach to industrial waste management by valorizing by-products that would otherwise contribute to environmental degradation. Thus, the cosmetic industry is positioned to benefit significantly from integrating these bioactive compounds into its product lines, offering consumers effective, natural, and high-tech beauty solutions [1].

Aligned with this perspective of more green and highly effective cosmetics, nanotechnology has emerged as a transformative approach to developing sustainable, high-performance cosmetic products. By facilitating the manipulation of materials on a molecular scale, this technology enhances the bioavailability and efficacy of cosmetics derived from plant and animal waste. These natural nanoparticles (NPs), synthesized using biological methods, are advantageous due to their cost-effectiveness, environmental sustainability, and low toxicity. They also offer a range of beauty benefits, including antioxidants, anti-aging, moisturizing, depigmentation properties, and sun protection. They can be incorporated into various beauty products such as skin, body, and hair care. This innovative application of nanoscience in cosmetics paves the way for creating efficient delivery systems. It promotes the utilization of bioactive molecules and substance classes from waste materials in a more effective and targeted manner [8,9,10]. Although incorporating nanotechnology into cosmetic products on a large scale presents several potential challenges, they must be addressed to ensure consumer safety and regulatory compliance. One of the primary concerns is the potential toxicity of nanomaterials, as their small size and unique properties may lead to unanticipated biological interactions within the human body.

Integrating nanocarrier systems in skincare products has significantly enhanced the delivery and efficacy of bioactive compounds, leading to improved skin health and appearance. For instance, Dior’s Capture Totale line uses liposomes to deliver longoza extract and hyaluronic acid, enhancing penetration and absorption, which results in improved hydration, reduced wrinkles, and increased firmness [11,12]. Similarly, La Prairie’s Cellular Power Charge Night employs nanostructured lipid carriers (NLCs) for the stable and sustained release of retinol and peptides, resulting in smoother and more radiant skin [13]. These advancements illustrate the transformative impact of nanotechnology in the cosmetics industry, specifically in meeting consumer demands for more effective and sustainable skincare solutions. Consumers increasingly seek products that deliver visible results, are easy to use, and are environmentally friendly. Nanotechnology in skincare products addresses these demands, making it a significant development in the industry.

Additionally, the lack of comprehensive understanding regarding the long-term effects of nanoparticle exposure on human health and the environment poses a significant challenge, as the potential risks may still need to be fully known [14]. Regulatory authorities have also needed help to keep pace with the rapid advancements in nanotechnology, which are leading to uncertainty and the need for more robust safety assessment protocols. Another challenge lies in the scalability and cost-effectiveness of incorporating nanotechnology into cosmetic products on a large scale. Manufacturers must invest in specialized equipment and processes to ensure consistent quality and safety, which can increase production costs and limit the affordability of such products for consumers. A multifaceted approach is required to address these challenges, involving collaboration between industry, regulatory bodies, and the scientific community [15]. This paper summarizes the practical applications of different nanosystems in developing new beauty solutions, strongly emphasizing sustainability. It explores how nanotechnology enhances cosmetics’ efficacy and highlights the responsible use of plant and animal by-products, thereby minimizing environmental impact. This review underscores the potential for these high-tech methodologies to contribute to sustainable beauty practices, aligning product innovation with the urgent need for environmental stewardship in the cosmetic industry.

2. Sustainability in Cosmetics

The increasing global market for sustainable cosmetics, projected to reach USD 937.13 million by 2030 with a compound annual growth rate of 7.7% from 2024 to 2030, underscores the imperative for cosmetic brands to adopt more sustainable practices [16]. This growth reflects a crescent consumer demand for ethically sourced, environmentally conscious, and energy-efficient products. The 2030 Agenda for Sustainable Development emphasizes goals such as responsible consumption and production (SDG 12), climate action (SDG 13), and life on land (SDG 15), which are directly relevant to the cosmetics industry. The industry can contribute to global sustainability by aligning with these goals while enhancing its market appeal [2].

The lifecycle assessment (LCA) is a critical tool for evaluating the environmental impact of cosmetic products from cradle to grave. It helps identify hotspots for improvements, such as raw material sourcing, production processes, packaging, and end-of-life disposal. Implementing LCA allows companies to make informed decisions that reduce their environmental footprint. Good practices in sustainable cosmetics production include ensuring that raw materials are sourced sustainably and ethically, respecting both biodiversity and local communities; utilizing environmentally friendly chemical processes and reducing hazardous substances; adopting recyclable, biodegradable, or reusable packaging materials; and investing in energy-efficient technologies and renewable energy sources to power manufacturing processes [4]. Some brands have successfully integrated sustainability into their operations and product lines. Lush, for instance, has set a notable example by implementing initiatives that reduce environmental impact, such as ethically sourcing raw materials, employing minimal packaging, and actively campaigning against animal testing. Moreover, Lush’s investment in technologies to reduce energy consumption and its carbon footprint illustrates a comprehensive approach to sustainability [17,18].

Traditional cosmetic production poses various environmental challenges, including deforestation, habitat destruction, loss of biodiversity from extracting natural ingredients, and pollution from synthetic chemicals. The industry’s reliance on extensive packaging further exacerbates waste issues [1,19]. Recognizing these impacts, the cosmetic industry is increasingly driven to revise its practices. For instance, repurposing waste materials mitigates environmental impact and aligns with consumer expectations for sustainable products, thus fulfilling ecological and market demands [20,21].

The commitment demonstrated by companies like Lush has served as a significant catalyst in the cosmetics industry, encouraging other brands to reassess their operational and production strategies to prioritize environmental stewardship. By successfully showcasing their sustainability efforts, Lush and similar companies not only shape the future landscape of the cosmetic industry but also amplify the importance of aligning business practices with consumer values of sustainability and ethical sourcing. This sector-wide shift towards eco-conscious practices underscores the industry’s responsiveness to growing consumer preferences for cosmetics featuring natural plant-based active ingredients [18].

The escalating consumer preference for sustainable and natural cosmetics aligns with environmental goals and provides a platform to address the ecological impacts of industry by-products. However, the integration of plant-based actives into functional cosmetics is complicated by technical challenges such as limited solubility, stability, skin permeability, and potential irritation of the actives. These issues restrict their widespread adoption in the market despite their eco-friendly appeal and potential health benefits [22].

In this context, L’Oréal, founded in 1909 by Eugène Schueller, exemplifies Brand Activism (BA) with its strong commitment to sustainable product development. Initially specializing in hair colorants, L’Oréal has evolved into a leading global manufacturer of beauty products and cosmetics, including renowned brands like Maybelline, Lancôme, and Kiehl’s. The company’s growth over the years is a testament to its adaptability and innovation within the cosmetics industry. L’Oréal’s reputation for sustainability and ethical practices is well-established, and it is recognized consistently by Global RepTrak as one of the top 100 most reputable companies [23].

A pivotal element of L’Oréal’s brand activism is demonstrated through its Lancôme brand, which is deeply committed to protecting, preserving, and restoring biodiversity. Lancôme’s strategic approach includes sustainable cultivation and sourcing practices, complemented by fair trade agreements, to minimize its agricultural footprint. The brand also leverages green chemistry and biotechnology to reduce the consumption of natural resources. Furthermore, Lancôme is advancing its sustainability agenda using more recyclable materials in its packaging and extending its environmental initiatives beyond its direct operations by sponsoring leading institutions and biodiversity conservation projects. These efforts underline Lancôme’s proactive role in environmental stewardship, providing a foundation for incorporating advanced technologies such as nanotechnology. This technological integration aims to enhance its products’ efficacy and sustainability, setting a new benchmark in the cosmetics industry for balancing innovation with environmental responsibility [24].

Also, the adoption of nanometric cosmetic structures containing lipid globules of 10–100 nanometers in size by Lancôme in 1987 has gracefully increased the performance of their products while reducing their environmental impact. Some examples of the application of nanotechnology that the brand uses in its products include niosomes, silver nanoparticles, and nanocapsules [25].

3. Sources of Plant and Animal Waste

Food processing waste can yield several highly valuable cosmetic by-products (Figure 1). Animal, vegetable, and marine industries generate many residues with high profitable potential [26].

Animal by-products are mostly from fisheries, poultry, and red meat residues, originating structural fibrous proteins such as collagen, elastin, and keratin from feathers, scales, cones, and hooves. Collagen peptides act as a cosmetic active for skin reaffirmation and hydration; they can be recovered from pig skin or bovine hide. Elastin is present in many residues, especially from chicken parts, representing 70% of the dry weight, but also from the skin of fish and pigs, which is applied as a moisturizer in face and body cream. Last, keratin is utilized from discarded wool, feathers, and porcine hairs in its whole form or hydrolyzed peptides for skin elasticity and hydration [26,27].

Studies applying collagen, elastin, and keratin peptides (<1000 Da) in aqueous solutions have determined benefits beyond hair care for keratin but also remarkable potential for skin barrier integrity reinforcement and improvement of water holding. Obtaining these peptides from residues is widely used, and there are several methods for obtention, such as enzymes (proteases and collagenases) and hydrolysis using acid or alkali followed by heat [27,28].

In addition to their potential applications as cosmetics actives, animal by-products are often replaced by synthetic or vegetable substances, as they raise ethical issues against animal suffering and cruelty. Certifications as vegan or halal can be provided for formulations containing animal components once they do not cause any harm to nonhuman animals, i.e., snail slime. However, it can’t meet “cruelty-free” consumer demand if provided from the slaughterhouse and fish industries by-products [29].

Vegetable waste, widely studied and applied in many sectors, generates the most diversity of molecules that can be used as cosmetic ingredients. Such high-value-added by-products are mainly provided through vegetable secondary metabolites, which have no nutritional value for human consumption but are essential for plant protection against biotic and abiotic stress [30,31].

Fruit and vegetable by-products can be obtained as waste during processing or from discharged materials without being of sufficient quality for consumption. Beverage production produces vast amounts of waste, such as skin, seeds, stems, leaves, coffee beans, wastewater, and unusable pulp. The composition of the residues is rich in fibers, pectin, polysaccharides, phenolic acids, carotenoids, tocopherols, flavonoids, vitamins, and aromatic compounds with a higher quantity of bioactive compounds than the main product [30,31].

Rich in fatty acids and phytosterols, squalene oil seed obtained from pomegranate (Punica granatum) indicated a potential use as a by-product active for cosmetics; the oil’s extraction was performed through solvent extraction (n-hexane), assisted by centrifugation and an ultrasonic bath. Each oil’s gram has 2.0 mg/g of squalene, a natural isoprenoid and intermediate of sterol biosynthesis that acts as a skin emollient and antioxidant [32].

Citrus unshiu fruit peels are a promising candidate for skin pigmentation disorders. An extract produced by ethanol showed the capacity to inhibit tyrosine activity, an essential key for melanin synthesis. Its activity is related to the extracted compounds (limonene (80.5%), γ-terpinene (6.80%), cymene (4.02%), β-myrcene (1.59%), α-pinene (1.02%), and α-terpinolene (0.56%)) [1,33].

Tomato lycopene is the most exciting by-product in the cosmetic industry. Its effect against UV-induced damage is widely recognized, and it is used as a natural source for sunscreen active formulations with SPF 20. Recovered from peels, pulps, and seeds, it is also called “tomato pomace.” It can be extracted by food-grade solvents (hexane, ethanol, and ethyl acetate) [1,34].

The olive oil (Olea europea) extraction process generates a water-soluble fraction named Oil Vegetation Waters (OVW). These are separated from the oil and can be used as a by-product for cosmetics due to phenolic compounds (hydroxytyrosol and oleuropein) that have antioxidant activity and a detoxifying effect on cultured skin cells [1,35].

By-products from white wine production with grape marcs of Aglianico grapes perform several activities in the corneum stratum as a cosmetic skincare ingredient. The lipophilic extract obtained by liposoluble solvent not dissolved in the juicy during pressing; these oily compounds are mostly resveratrol, lycopene, ellagic acid, and especially carotenoids act as a skin detoxifying agent by increasing proteasome activity by 44% in fibroblasts and 61% in keratinocytes, stimulate new collagen production through a higher expression level of collagen I and III, and boost the hydrating potential [1].

Unused beans from coffee plants (Coffea Arabica and Coffea robusta) are a precious source of antioxidants that have not been depleted by the roasting process. Unroasted coffee beans extracted through subcritical water extraction (SWE) with ethanol have improved natural skin cell renewal, skin antiaging, and lightening effects by inhibiting elastase and tyrosinase, an essential factor for melanin synthesis. This activity correlates to the bean extract’s phenolic acid compounds [36].

Several marine bioactive compounds can be used as marine by-products for cosmetic purposes; heads, guts, scales, shells, and bones from marine animal and algae species have been studied as applied in high-priced cosmetic formulations [28,37].

Marine species skin waste from Takifugu flavidus presents a remarkable collagen obtention extraction; collagen bioactive peptides with lower molecular weight provide more potent antioxidant effects with high potential in skincare formulations; extracted by electrodialysis with a purity of 96.1%, a new technique (electrodialysis) for the extraction of T. flavidus skin displayed better economic and environmental outcomes, reducing the purification time and wastewater, maintaining a high extraction yield (67.3 g/100 g dry weight), and presenting viability using this by-product in the beauty industry [28,38].

Crustacean by-product is significant for astaxanthin presence as a red fat-soluble pigment, extracted from carapaces with different extract methods such as organic solvent, oil, and the green extraction technique using ethanol, assisted by column chromatography to obtain pure astaxanthin; it can be applied in cosmetic nanoemulations; its benefits are described through topical application against UV damage, such as avoiding skin thickening, reduced collagen loss, and topical application of astaxanthin-liposomal cationic lipid suppressed melanin synthesis in UV-exposed skin [28,39].

Considered the primary producers, algae and microalgae are a diverse group of aquatic macroscopic eukaryotes, also known as seaweed. Cosmetic industry interest in algae is due to the diversity of compounds, such as polysaccharides (alginates, agar, carrageenans, or fucoidans), minerals, lipids, proteins, and secondary metabolites (phenolic compounds, terpenes, halogen compounds, carotenoids, vitamins, and sulfur and nitrogen derivatives) [37,40].

On the coast of Galicia, brown algae, such as Laminaria sp. and Saccharina sp., produce high-quality alginates, a polysaccharide described as having a better moisturizer capacity than hyaluronic acid; their extraction occurs enzyme-assisted, and they present applications in skincare products [39,40].

Sustainable cosmetics with industry by-products are considered a science yet to be developed. The standardization of methods and tools is necessary to define animal, vegetable, and marine by-product applicability and real environmental impact, not to mention quality, consumer demand, safety, and the economic feasibility of their production processes [41,42,43].

Implementing transparent supply chains is crucial to achieving sustainability and ethical sourcing in the cosmetics industry. Transparent supply chains significantly contribute to the sustainability and ethical sourcing of plant and animal by-products in nanotechnology-based cosmetics by ensuring accountability, traceability, and informed consumer choices. By enabling the verification of ethical sourcing, companies can ensure that ingredients are harvested in ways that do not harm ecosystems or exploit workers, maintaining high standards of environmental and social responsibility [44]. Additionally, these supply chains facilitate sustainable practices by allowing companies to monitor and optimize each step of the production process, thus reducing waste and minimizing the carbon footprint [45]. Building consumer trust is another critical aspect, as clear information about sourcing and production processes drives demand for sustainably sourced products and encourages adopting eco-friendly practices within the industry [46]. Therefore, transparent supply chains are essential for promoting sustainability and ethical sourcing in the cosmetics sector.

4. Nanotechnology in Cosmetics

Over the past few years, research has focused on the application of nanotechnology in medicine, but its approach to developing cosmetic products is becoming more widely known. An example is its applicability in cases of skin diseases, such as for the treatment and diagnosis of skin cancer [47] and treatment of skin wounds [48], as well as for use in formulations that improve aesthetics, such as those intended for the treatment of anti-aging [49,50] and lightening of blemishes [51,52], among others. In most studies, it is observed that nanoparticles (NPs) have been shown to improve the bioavailability of active ingredients and enhance the cutaneous penetration of macromolecules, ensuring adequate basal levels of active ingredients to achieve therapeutic success.

Nanocarriers significantly enhance the delivery and effectiveness of natural waste-derived bioactive compounds in cosmetics by leveraging their small size, high surface area, and ability to protect and release bioactives in a controlled manner. For instance, the use of lipid-based nanocarriers such as liposomes and solid lipid nanoparticles has shown to improve the stability and bioavailability of bioactives like curcumin and resveratrol, which are derived from natural sources like turmeric and grapes, respectively [53,54]. These nanocarriers protect the bioactives from degradation and enhance their penetration through the skin, thereby increasing their effectiveness in cosmetic applications. Additionally, the integration of bio-wastes, such as pectin from fruit peels and chitosan from shellfish waste, into nanocarriers not only promotes sustainability but also enhances the delivery of antioxidants and other beneficial compounds in skincare products [55]. This innovative approach aligns with green technology strategies and supports the development of eco-friendly and efficient cosmetic formulations [53].

Companies worldwide use NPs in their products to increase the concentration of active substances and control their delivery. For example, the manufacturer Dior has developed a facial moisturizer using liposomes, and Boticário produces an anti-aging product that includes a complex of vitamins in its formulation through NPs. Both products contain liposomes in their formulations [56,57]. NPs give cosmetic formulations more remarkable elegance and innovation. Chantecaille, Nuvoderm, O3+, and Tony Moly are some examples of manufacturers that have developed products that incorporate gold NPs in their composition, mainly in formulations that repair skin damage and improve facial aesthetics [58].

Other NP approaches that favor the cutaneous permeation of active ingredients is the possibility of modifying the hydrophilic/hydrophobic profile by altering the surface of the active ingredient [59,60,61], changing its surface charge [62], and adjusting the shape [63], since studies have shown that variations in all these aspects may or may not contribute to better skin permeability. L’Oreal and Lancôme recurrently use NPs in their formulations to achieve the above chances, from products containing retinol encapsulated in nanosomes to some containing nano-encapsulated ceramides [57].

Nanotechnology is very productive when applied to cosmetic products because it can overcome some typical limitations commonly observed in cosmetic products. Some research focuses on the development of new vehicles for cosmetics based on natural actives and containing fewer irritating ingredients, such as dyes, preservatives, and emulsifiers, among others [64] and on the improvement of vehicles and sunscreen components, making them more photostable, hydrophilic, and potent against UVB and UVA rays [65,66]. Dior and Lancôme are companies that apply NPs to several of their products, such as a lip care product containing nano-encapsulated vitamin E to reduce wrinkles and a nano-UV-based sunscreen that protects the skin more effectively against UVA and UVB rays [57].

The cosmetic hair care market has also expanded the use of NPs in its products. Both hair care and enhancement products are constantly innovating, so new products can better interact with the hair fibers, using fewer active ingredients and presenting fewer toxic or irritative effects to the user [67]. Nutraliss produces a line of shampoos and conditioners containing sericin NPs and organic extracts that promise to prolong the hair’s softness and color for longer. Facinatus Cosmetics, on the other hand, has developed a moisturizing shampoo containing nano-encapsulated batana oil, which makes the formulation more penetrating the hair [68].

With the advancement of more sustainable product ideals, including substances of plant origin, using by-products in cosmetic formulations has become common practice. The main challenges with this type of ingredient are low solubility, reduced skin permeation, and the possibility of instability in the formulation. However, these problems can be overcome with NPs to act as delivery systems for these compounds or synthesize the plant compounds [69]. Another innovative delivery system is based on cyclodextrins, which are cyclic oligosaccharides with hydrophobic and hydrophilic portions, enabling the formation of complexes with good stability, high encapsulation efficiency, and low toxicity. This system has been widely used in both the cosmetics and pharmaceutical industries, mainly to improve the end product’s characteristics, such as stability and solubility, and modulate some drugs’ profiles [70,71]. Among the main cosmetic formulations containing some form of cyclodextrin for skin treatment are those intended to treat skin cancer, dermatitis, diseases of microbiological origin, acne, and psoriasis [71].

The applicability of NPs in cosmetic products should be analyzed according to their objectives and the material with which the nanocarriers will interact. In general, the different types of nanocarriers aim to provide the formulation with greater stability, better skin permeation, and targeted and controlled delivery of active ingredients [72]. Several NPs, such as lipid, polymeric, and metallic NPs (Figure 2), can be applied in this field.

Cosmetic companies face several regulatory challenges when adopting advanced technologies like nanotechnology, including the lack of specific regulations tailored to nanomaterials, the complexity of comprehensive safety and risk assessments, and the inconsistency in standardized testing methods across different regions. European regulations emphasize the importance of detailed safety assessments and compliance with specific safety and labeling requirements for nanomaterials [73]. Similarly, the absence of a unified definition and regulatory framework for nanomaterials complicates international trade and consumer safety assurances, with regulatory agencies like the FDA and EU beginning to develop guidelines but significant gaps remaining [74]. Nanomaterials’ long-term health and environmental impacts pose further challenges, necessitating advanced, standardized testing methods and lifecycle assessments to address these uncertainties [75]. Developing clear, specific guidelines that define nanomaterials, establishing robust safety protocols, and harmonizing international regulations are essential to foster innovation while ensuring safety. Enhancing transparency and consumer education through clear labeling and informative marketing can build trust. Collaborative research efforts among industry, academia, and regulatory bodies are crucial to advancing safe nanotechnology applications. At the same time, international harmonization of regulations and testing methods can streamline the approval process and facilitate global market access. Implementing these measures can ensure the development of innovative, sustainable, and safe cosmetic products.

4.1. Lipid NPs

First described in the 1960s, lipid nanocarriers are the most traditional and studied models. They include liposomes, microemulsions, solid lipid NPs (SLN), and nanostructured lipid carriers (NLC) [59]. Table 1 summarizes the articles using lipid NPs in cosmetics.

Liposomes are spherical vesicles with a lipid bilayer lining an aqueous interior cavity. Their size can vary between 0.025 and 2.5 μm and be unilamellar or multilamellar [76]. This type of nanocarrier has a highly biocompatible, biodegradable profile, and it is considered low toxicity and very protective against enzymatic degradation of drugs, which has popularized its use in cosmetic and pharmaceutical products [77]. Other positive features include the possibility of encapsulation of hydrophobic and hydrophilic particles, ease of preparation, and good applicability for topical products [78,79]. However, this system has some limitations: low stability, low encapsulation efficiency, and a short lifetime. The added value can also be an issue in cosmetic products [80].

Micro and nanoemulsions are dispersions of two immiscible liquids, which may be oil-in-water (o/w) or water-in-oil (w/o) and are stabilized by the presence of an amphiphilic emulsifier [81,82]. These systems can range from 20 to 200 nm in size, are transparent, and have been widely used in cosmetic products for cleansing and skincare products [83]. This vehicle’s formation requires some components, including lipids, surfactants, preservatives, and antioxidants [84]. They are vehicles of simple preparation and good reproducibility. They can be used in various products, including creams, gels, sprays, and formulations for topical, oral, intramuscular, and intravenous administration [85].

These colloidal solutions have rheological and optical properties that improve the delivery of active ingredients, especially those based on fatty compounds [86]. Their small size also reduces Brownian motion and gravitational forces, preventing product sedimentation and creaming [83]. Its small size promotes several benefits, especially for the skin, which stand out: promotion of skin hydration, reduction of transdermal water loss, increase of skin permeability of active ingredients. In addition, they also have good stability, low viscosity, and can be used as a vehicle for lipid substances [87,88]. Another differentiating point of this system is that they do not block pores, which is a desirable feature for formulations intended for the face [89].

Solid lipid NPs and nanostructured lipid carriers have emerged as alternatives to traditional nanocarriers and are commonly referred to as first- and second-generation NPs, respectively [90]. SLNs are spherical particles based on surfactants and lipids, which can be glycerides, triglycerides, or waxes. These particles are solid at room and body temperature and have an average size between 40 and 1000 nm. In their composition, surfactants can appear in concentrations between 0.5 and 5%, depending on the desired stability of the nanoparticle and the drug used [91,92,93].

Presenting a more stable profile and promoting a more controlled drug delivery when compared to liposomes, these NPs have several positive points, including increased bioavailability, low toxicity and the ability to remodel the pharmacokinetic profile of drugs [94]. The presence of lipid solvents is also not necessary in this system [95]. Regarding the negative points, it is worth mentioning that this type of system, due to its structure, does not allow the incorporation of high amounts of active substances, in addition to the possibility of gelling depending on the ambient temperature [96]. Such characteristics are due to coalescence, where lipid particles aggregate in droplets or crystals to reduce the surface area [97].

On the other hand, nanostructured lipid carriers (NLCs) have been developed as candidates to fill the gaps created by SLNs [98]. NLCs are composed of a liquid phase, oil, and a solid phase, resulting in a matrix with no defined shape. However, three shapes can be obtained depending on the manufacturing process: imperfect, shapeless, and multiple types [74]. Each shape has its differential, which gives the system an increase in the capacity of trapping the drug in the matrix, preventing the expulsion of the loaded drug, or favoring the solubility of lipid drugs.

Among the improvements presented are the ability to incorporate more active ingredients, better stability, and a system that prevents the expulsion of the drug from the particle [99]. These advantages are obtained due to the use of liquid lipids, which disrupt the formation of perfect lipid crystals and increase the spaces between the crystals, favoring the incorporation of drugs [100]. In this way, the risk of gelation is also avoided in this system [96]. In general, lipid nanocarriers are widely used in the industry, and their ability to deliver drugs and better skin penetration favors their application in a wide range of products [90].

Lipid-based nanocarriers, including solid lipid NPs (SLN), nanostructured lipid carriers (NLC), nanoemulsions (NEs), and liposomes (LPS), play a pivotal role in the formulation of high-value cosmetics derived from industrial by-products of plant and animal origin. These nanocarriers offer unique advantages in cosmetic applications because they can efficiently encapsulate and deliver hydrophilic and lipophilic bioactive compounds. By harnessing their biocompatible nature, these nanocarriers can enhance active ingredients’ stability, solubility, and bioavailability, thereby improving the efficacy of skincare and beauty products. Moreover, their lipid composition ensures compatibility with the skin’s natural barrier, minimizing the risk of irritation or adverse reactions, making them ideal candidates for advanced cosmetic formulations [101,102,103].

Mostafa et al. (2021) proposed the use of SLN to explore the antioxidant potential of peach tree (Prunus persica (L.)) leaves, which, alongside other by-products from this plant (like seeds and flowers), have been reported to have cosmetic and dietary properties of industrial interest due to their high flavonoid content. The leaf extract (PPEE) was obtained using hot 75% ethanol:water extraction followed by solvent evaporation. This extract was characterized by a unique acylated kaempferol glycoside with a rare structure, kaempferol 3-O-β-⁴C₁-(6″-O-3,4-dihydroxyphenylacetyl glucopyranoside) (KDPAG) was isolated. Extract-loaded SLN (PPEE-SLN) was obtained using solvent evaporation and formulated into a cream (2 and 5%). Both PPEE and PPEE-SLN demonstrated desirable in vitro cytocompatibility in human keratinocytes. Additionally, PPEE-SLN showed a superior antioxidant effect compared to ascorbic acid. Formulations were tested regarding their inhibitory effects on skin aging-related enzymes, including elastase, collagenase, and tyrosine kinase. In all cases, PPEE-SLN significantly inhibited enzymatic activity (>78%), and for collagenase and tyrosine kinase, extract encapsulation showed significantly higher inhibitory activity compared to EDTA and kojic acid, respectively. The authors performed in vivo studies in mice models to assess the anti-wrinkling properties of PPEE-SLN cream. After UV exposure for 30 days, animals treated with the 5% PPEE-SLN cream showed a significantly superior anti-wrinkling score, compared to a marketed formulation, with attenuated histological alterations and UV-stress biomarker (superoxide dismutase) levels like healthy skin [52].

Krasodomska and coauthors proposed using NLC as a nanotechnological intervention to repurpose fruit seeds that are usually considered waste but can originate oils rich in polyunsaturated fatty acids (PUFAs) of cosmetic interest. In their study, the authors used cold-pressed seed oils obtained from the waste material of domestic fruits, including blackcurrant, blackberry, raspberry, strawberry, and plum. To formulate NLCs, the authors used bee was as a solid lipid and two non-ionic surfactants, Myverol^® RX GMS 95P (a mixture of glycerol palmitic (57.8%), stearic (37.3%), and myristic (1.3%) acid monoesters) and Chemal OA-20 (a mixture of ethoxylated palmitic and stearic alcohols). The best oil incorporation was achieved using a proportion of 6:2 of bee wax:oil. After oxidative stability tests using UV radiation (400 nm), NLC formulations showed the lowest peroxidation values (PV), followed by the emulsified oils, and the highest PV was found for the raw oils, suggesting a possible degradation of PUFAs when exposed to UV radiation. At the same time, NLC effectively protected them from degradation [104].

Rodrigues and colleagues also proposed using NLC to explore the potential of caffeine from coffee silver skin (CS) to treat cellulitis. CS is a thin layer that covers coffee seeds and is produced in large amounts as a by-product during the coffee roasting process. Caffeine was extracted from silver skin by maceration for 30 min at 40 °C with 20 mL of ethanol:water (1:1). Caffeine-loaded NLC (C-NLC) were obtained using Precifac^® ATO and Miglyol^® 812 as solid and liquid lipids, respectively, and polysorbate 60 as surfactant, using the emulsification-sonication method. C-NLC presented desirable colloidal stability over 180 days. Using pig skin, the authors demonstrated that caffeine has superior permeation compared to an ethanolic caffeine extract when delivered by NLC, potentially contributing to improved skin delivery [105].

Yang et al. (2017) developed NEs containing coffee oil extracted from coffee grounds using another coffee by-product. Coffee oil was associated with algae oil, and NEs were produced using sorbitan oleate and polysorbate 80 as surfactants using the emulsification-sonication technique. HaCat cells irradiated with UVA (365 nm) and UVB (312 nm) showed decreased cell viability. After treatment with the NEs (0.01%), only UVA-irradiated cells partially recovered their viability in ~14%, suggesting that coffee oil-algae oil NEs were effective in repairing UVA-induced cell damage. Using BALB/c mice, the authors investigated the in vivo protective effect of the NEs. The authors demonstrated no irritative potential of NE in the skin. Additionally, 0.1% NEs reduced water loss, erythema, melatonin formation, and skin inflammation in a 6-day study [106].

Phospholipids represent an essential class of macromolecules with great food and cosmetical applications. The oil industry produces them large-scale (150 thousand tons annually), which are considered waste products. To address the economic and ecological impact of phospholipid production, recent studies have been aimed at establishing new production alternatives and increasing the market value of phospholipids. Szczepańska et al. (2022) proposed a biological method to produce phospholipids in high yield from crude glycerol, which contains many impurities, including heavy metals, methanol, and salts, resulting in a low market value, using the yeast Yarrowia lipolytica [107].

In the context of increasing the market value of phospholipids, Lee et al. (2022) also explored the potential of biological methods to improve the market value of phospholipids, in particular soy lecithin, which can have some economic potential but is limited by its low aqueous solubility and dispersibility. Using two different enzymes (a phospholipase A2 from Streptomyces violaceoruber (Sv-PLA2) and a photoactivated decarboxylase from Chlorella variabilis NC64A (Cv-FAP)), they converted lecithin liposomes into lysolecithin and free fatty acids, hydroxy fatty acids, secondary fatty alcohols, or hydrocarbons molecules and in liposomal form, which can be relevant to improve their physicochemical properties as food and cosmetic ingredients [108].

Many animal and citrus production by-products have potential applications as active ingredients in the food, cosmetic, and pharmaceutical industries. However, their use is limited by their poor water solubility. With that in mind, Azmi et al. (2022) developed lemon and fish by-product oils NEs (NE-FLO) to improve both these actives’ stability and solubility. NE-FLO was obtained using high-shear homogenization followed by sonication. The NE-FLO demonstrated antibacterial activity against several gram-positive and gram-negative bacteria. NE-FLO also showed no toxicity against normal human fibroblasts (HSF 1184), even in high concentrations (10 mg/mL). The anti-inflammatory activities of the NE-FLO were remarkably high and equivalent to compared to the nordihydroguaiaretic acid (positive control). NE-FLO also exhibited desirable antioxidant activity compared to ascorbic acid (positive control). This strategy allows for the better use of animal and vegetal by-products for skin care by improving their stability and solubility [109].

The red raspberry (Rubus idaeus L.) seed oil (RO) is another example of a vegetal by-product rich in active compounds that can be useful as cosmetic ingredients. RO is rich in PUFAs. Gledovic et al. (2022) proposed using NE-containing RO (RO-NE). These NE were obtained using non-ionic surfactants via the isothermal phase inversion composition method. RO showed a synergistic effect with moderate protection using butylhydroxytoluene (BHT) at 40 °C regarding temperature-triggered degradation. Regarding the different surfactants used, polysorbate 80 exhibited a prooxidative effect. In contrast, polyglycerol ester-based surfactants showed increased oxidative protection at room temperature, especially at 40 °C, compared to polysorbate-based NEs [110].

Table 1. Characterization and application of lipid nanoparticles in cosmeceutical formulations.

Type of Nanoparticle	Composition	Active Ingredient	Characterization	Physical-Chemical Properties	Formulation	Biological Performance	Reference
SLN	Glyceryl monostearate, polysorbate 80	KDPAG	DLS, in vitro release and cytocompatibility, antioxidant and anti-aging properties, in vivo anti-wrinkling activity, histological analysis and SOD activity	170–176 nm, PDI 0.23–0.45, ZP −22 mV	Cream	Controlled release, cytocompatibility in human keratinocytes, improved antioxidant, anti-aging, and anti-wrinkling activities	[52]
NLC	Bee wax, Myverol® RX GMS 95P, Chemal OA-20 and different fruit seed oils (blackcurrant, blackberry, raspberry, strawberry and plum)	PUFAs	Differential scanning calorimetry, proton nuclear magnetic resonance, DLS, oxidative stability	274–355 nm, PDI 0.15–0.44, ZP −28–−38.5 mV, pH 3.9–4.2	-	Increased protection against oxidative degradation	[104]
NLC	Precifac® ATO, Miglyol® 812 and polysorbate 60	Caffeine	DLS, in vitro permeation and cytocompatibility, colloidal stability, morphology	178–183 nm, PDI > 0.25, ZP −23–−30 mV	-	Spherical morphology, increased skin permeation, dose-dependent cytotoxicity in human keratinocytes, desirable colloidal stability	[105]
LPS	Soy lecithin, 50 mM Tris-HCl buffer (pH 8.0)	Lysolecithin	DLS, morphology	84–144 nm	-	Spherical vesicles, successful modification of soy lecithin into lysolecithin, and production of oleic and linolenic acids.	[106]
NEs	Catfish oil, lemon oil, polysorbate 80, anionic co-surfactant	PUFAs + antioxidants	DLS, antioxidant, antibacterial, anti-inflammatory and cytotoxic properties	44 nm, PDI 0.07, ZP −5 mV	-	Increased antioxidant properties, broad antibacterial spectrum, anti-inflammatory properties, and cytocompatibility in human fibroblasts	[109]
NEs	Raspberry seed oil, polysorbate 80 or polyglycerol ester mixture as surfactant + association with different (natural or synthetic) antioxidants	PUFAs	DLS, oxidative stability	41–255 nm, PDI 0.059–0.125	-	Increased protection against temperature-induced oxidative degradation	[110]

DLS: dynamic light scattering, PDI: polydispersity index, PUFA: polyunsaturated fatty acid.

Table 1. Characterization and application of lipid nanoparticles in cosmeceutical formulations.

Type of Nanoparticle	Composition	Active Ingredient	Characterization	Physical-Chemical Properties	Formulation	Biological Performance	Reference
SLN	Glyceryl monostearate, polysorbate 80	KDPAG	DLS, in vitro release and cytocompatibility, antioxidant and anti-aging properties, in vivo anti-wrinkling activity, histological analysis and SOD activity	170–176 nm, PDI 0.23–0.45, ZP −22 mV	Cream	Controlled release, cytocompatibility in human keratinocytes, improved antioxidant, anti-aging, and anti-wrinkling activities	[52]
NLC	Bee wax, Myverol® RX GMS 95P, Chemal OA-20 and different fruit seed oils (blackcurrant, blackberry, raspberry, strawberry and plum)	PUFAs	Differential scanning calorimetry, proton nuclear magnetic resonance, DLS, oxidative stability	274–355 nm, PDI 0.15–0.44, ZP −28–−38.5 mV, pH 3.9–4.2	-	Increased protection against oxidative degradation	[104]
NLC	Precifac® ATO, Miglyol® 812 and polysorbate 60	Caffeine	DLS, in vitro permeation and cytocompatibility, colloidal stability, morphology	178–183 nm, PDI > 0.25, ZP −23–−30 mV	-	Spherical morphology, increased skin permeation, dose-dependent cytotoxicity in human keratinocytes, desirable colloidal stability	[105]
LPS	Soy lecithin, 50 mM Tris-HCl buffer (pH 8.0)	Lysolecithin	DLS, morphology	84–144 nm	-	Spherical vesicles, successful modification of soy lecithin into lysolecithin, and production of oleic and linolenic acids.	[106]
NEs	Catfish oil, lemon oil, polysorbate 80, anionic co-surfactant	PUFAs + antioxidants	DLS, antioxidant, antibacterial, anti-inflammatory and cytotoxic properties	44 nm, PDI 0.07, ZP −5 mV	-	Increased antioxidant properties, broad antibacterial spectrum, anti-inflammatory properties, and cytocompatibility in human fibroblasts	[109]
NEs	Raspberry seed oil, polysorbate 80 or polyglycerol ester mixture as surfactant + association with different (natural or synthetic) antioxidants	PUFAs	DLS, oxidative stability	41–255 nm, PDI 0.059–0.125	-	Increased protection against temperature-induced oxidative degradation	[110]

DLS: dynamic light scattering, PDI: polydispersity index, PUFA: polyunsaturated fatty acid.

4.2. Polymeric Nanoparticles

Another widely used class of nanocarriers is those of polymeric origin. This type of NP’s main advantages are increased drug stability, co-encapsulation ability, and potential side effects reduction [111]. The polymers that form these NPs can be of synthetic or natural origin, and their biocompatibility and biodegradability must be considered when choosing the polymer to be used [112]. Table 2 summarizes the articles using polymeric nanoparticles for cosmetics use.

Due to their excellent skin penetration, dendrimers have emerged as a new class of nanoparticles for topical pharmaceuticals and cosmetics. They are polymeric NPs known for their highly organized structure composed of repeated branches originating from a focal point and terminating in different anionic, cationic, or neutral functional groups on the surface [113,114]. The presence of other groups gives dendrimers a hydrophobic or hydrophilic profile. They are particles characterized as spherical, homogeneous, radially symmetric, and monodispersed [115].

Among their features is their structural and functional versatility, where it is possible to adjust their size, branch length, surface functionality, and other characteristics, allowing the system to be tailored to the need and intended application [116]. Dendrimers also provide some agents to model harmful properties, such as improved stability and solubility and reduced toxicity [115]. Compared to other NP models, this class has a higher capacity to entrap large amounts of drugs, better permeability across biological barriers, high bioavailability, and biocompatibility [113]. However, several challenges limit the use of this particle. Its application in medicine requires that the physicochemical characteristics of the dendrimer be evaluated very well to analyze the risk/benefit of its use. Therefore, the choice of the spatial structure, the initial central atom, the number of branching layers, and the functional groups must be carefully chosen to modulate permeability, immunogenicity, and cytotoxicity [113,117].

On the other hand, micelles are highly technological and effective nanoparticles emerging as a revolution in the topical application of active ingredients. Micelles are amphiphilic polymeric nanoparticles formed by a core containing the dispersed liposoluble drug surrounded by a mixture of hydrophilic and hydrophobic copolymer blocks [118]. These nanocarriers can range in size from 10 to 200 nm and are formed from the polymer self-assembly process [119,120].

Its composition allows it to be used with a wide range of actives since the hydrophobic core enables the solubility of actives with the same profile, and the hydrophilic outer portion stabilizes the interior with the external environment [119]. This type of particle has numerous advantages, including high encapsulation efficiency, reasonable production cost, and reduced particle size [86]. In addition, it also allows the encapsulation of poorly soluble and unstable drugs [121]. Recently, it has been widely used in cosmetic formulations for skin cleansing due to its ability to promote effective and gentle cleansing, which is considered superior to traditional products in the same category [122].

Another widely used polymeric nanocarrier is nanocapsules, particles formed by a polymeric membrane covering a core where the drug is dissolved [123]. This polymeric membrane is responsible for the controlled release of the drug through its pores and for preventing possible adverse effects [124]. Nanocapsules have an average size between 10 and 1000 nm and allow the local or systemic delivery of drugs. They are considered highly biocompatible, biodegradable, and stable in aqueous media [88].

These NPs generally allow the encapsulation of assets or assets with larger sizes and protect their loads. Another desirable feature is their highly specific surface, which enables receptor-ligand binding, favoring cell signaling and interaction processes [125]. Nanocapsules are widely used in sunscreen formulations due to their ability to reduce the permeability of the active ingredient into deeper layers of the skin, leaving only a thin surface layer. They are also commonly used to mask some of the characteristic odors of active ingredients that may affect consumer satisfaction and reduce the incompatibility of active ingredients in the formulation. However, some side effects may be observed when using this type of nanocarrier [86].

Flaxseed (Linum usitatissimum L.) is an oilseed with high nutritional value that is used in food and feed. One of the by-products of its processing is flaxseed gum (FG) extracted from its husk. GL is a soluble dietary fiber composed predominantly of polysaccharides (80%) and proteins (9%) [126].

Li and collaborators [127] explored the negative charge of FG in the development of chitosan (CS) polymeric nanoparticles (NPs) using the ionic gelation technique for the stabilization of Pickering emulsions, which are emulsions stabilized by solid particles. The system’s objective was to promote the topical release of ferulic acid. CS NPs with sodium tripolyphosphate (STPP) were also prepared using the same technique for comparison. The interfacial tension values of the particles in diacylglycerol (DAG), which would be the internal phase of the emulsion, were lower for the CS-FG NPs than for the CS-STPP NPs, indicating a greater absorption capacity of the CS-FG NPs in the oil–water interface and suggesting that these can form layers of Pickering particles, promoting better stabilization of the emulsion. The CS-FG NPs showed a significantly higher three-phase contact angle (θ) than the CS-STPP NPs (84.7° and 52.6°, respectively). After incorporating hyaluronic acid and ferulic acid into the NPs, the contact angle of the nanoparticles was 85.5°, pointing to their greater tendency to stabilize Pickering emulsions. In physical stability studies, the authors reported that emulsions stabilized by CS-STPP NPs suffered a small phase separation after 30 days at temperatures of 25 and 35 °C, a behavior that was not observed in emulsions stabilized by CS-FG NPs. To determine lipid oxidation, the total aldehyde content of the emulsion was measured as the para-anisidine value (pAV). It revealed a significantly lower final pAV value for the emulsions stabilized by CS-FG NPs, indicating that the presence of FG in the NPs prevented lipid oxidation. Finally, in vitro cutaneous release studies using Franz diffusion cells, associated with ex vivo retention and distribution studies using confocal laser scanning microscopy, allowed us to observe a better penetration of ferulic acid through the stratum corneum in the emulsion stabilized by CS-NPs. FG was compared to CS-STPP NPs, as well as deposition in deeper layers of the skin [127]. The use of FG in nanoparticles was able to improve the stability of the emulsion and favors the topical administration of ferulic acid, an active substance of hydrophobic nature, without the need to incorporate chemical penetration enhancers that can irritate, with this being a desired residue for cosmetic use.

Olive leaves (Olea europaea L.) represent a class of agricultural by-products obtained from the olive industries that constitute an abundant source of biophenols, potent anti-inflammatory, antioxidant, cardioprotective, antimicrobial, antiviral, anti-ischemic, and hypolipidemic compounds [128,129]. Kesent and collaborators [129] encapsulated olive leaf extract (OLE) in poly(lactic acid) (PLA)-based NPs for subsequent incorporation into an O/W cream. OLE was obtained from the evaporation of dry olive leaves and characterized by high-performance liquid chromatography and luminol chemiluminescence assay, with secoiridoid oleuropein being the main phytochemical quantified (69.5%). PLA nanoparticles were prepared using the nanoprecipitation technique and presented satisfactory physicochemical characteristics. Furthermore, the results of thermal analyses demonstrated an apparent protection of the extract within the PLA matrix. The in vitro release study was carried out in phosphate buffer simulating the pH and temperature of healthy skin (pH 5.6 at 37 °C) and demonstrated a release peak in 2 h, releasing 15.7% of the OLE followed by a constant release rate for up to 168 h. For comparison, OLE-loaded NPs and pure extract were incorporated into an O/W cream. The 3-month stability studies showed no significant differences in aroma or rheology parameters, with no phase separation occurring in both emulsions. However, the cream with free extract showed changes in color and pH. OLE is sensitive to light, temperature and oxidation; therefore, the changes observed may be a sign of reactions that could lead to formulation instability and ineffectiveness of the extract [129]. The results suggest that the encapsulation of OLE in PLA NPs was preferable as it did not affect the stability and appearance of the cream and is considered promising for use in cosmetic formulations.

Although the number of studies using by-products in polymeric nanocarriers is limited, the results are promising and indicate that this is a potential area to be explored.

Table 2. Characterization and applications of polymeric nanoparticles in cosmetics formulations.

Type of Nanoparticle	Composition	Active Ingredient	Characterization	Physical-Chemical Properties	Formulation	Biological Performance	Reference
Polymeric nanoparticle	Chitosan, flaxseed gum, hyaluronic acid	Ferulic acid	Size, PDI, zeta potential, TEM, FT-IR, interfacial tension and wettability.	262.4 nm, PDI 0.25, zeta +36.2 mV	Pickering emulsion	Improved skin permeation and retention, increased stability in the emulsion	[127]
Polymeric nanoparticle	Poly(lactic acid), poly(vinyl alcohol)	Olive leaves extracts	Size, PDI, zeta potential, SEM, EE%, DSC, FT-IR.	246.3 nm, PDI 0.21, zeta −27.5 mV, EE 49.2%	Cream	Increased stability in the emulsion	[129]

PDI: polydispersity index, TEM: transmission electron microscopy, FT-IR: Fourier-transformed infrared, SEM: scanning electron microscopy, EE: encapsulation efficiency.

Table 2. Characterization and applications of polymeric nanoparticles in cosmetics formulations.

Type of Nanoparticle	Composition	Active Ingredient	Characterization	Physical-Chemical Properties	Formulation	Biological Performance	Reference
Polymeric nanoparticle	Chitosan, flaxseed gum, hyaluronic acid	Ferulic acid	Size, PDI, zeta potential, TEM, FT-IR, interfacial tension and wettability.	262.4 nm, PDI 0.25, zeta +36.2 mV	Pickering emulsion	Improved skin permeation and retention, increased stability in the emulsion	[127]
Polymeric nanoparticle	Poly(lactic acid), poly(vinyl alcohol)	Olive leaves extracts	Size, PDI, zeta potential, SEM, EE%, DSC, FT-IR.	246.3 nm, PDI 0.21, zeta −27.5 mV, EE 49.2%	Cream	Increased stability in the emulsion	[129]

PDI: polydispersity index, TEM: transmission electron microscopy, FT-IR: Fourier-transformed infrared, SEM: scanning electron microscopy, EE: encapsulation efficiency.

4.3. Inorganic Nanoparticles

Finally, another widely used nanocarrier type is the metallic or inorganic type. Inorganic nanoparticles are those derived from inorganic substances, with gold, zinc, copper, and silver being the most used elements [70]. Inorganic NPs are considered more biocompatible, hydrophilic, stable, and safe than other natural NPs and are also considered non-toxic [54]. Table 3 summarizes the articles using inorganic nanoparticles in cosmetics.

Titanium and zinc are widely used in sunscreen formulations due to their potential protection against UVA and UVB rays and low toxicity [130]. Silver and gold, on the other hand, are widely used in cosmetic formulations, mainly for their antifungal and antibacterial properties [58]. Silica nanoparticles improve the pigments present in cosmetic formulations and extend the shelf life of products, in addition to being considered a low-cost element that favors the prolonged distribution of active ingredients [131]. Other compounds, such as carbon fullerenes, nanohydroxyapatite, and carbon black, are also finding more and more applications in cosmetics [65,132,133].

The environmentally friendly scientific and technological development has gained emphasis over the last few years, aiming not only for efficacy but also for environmental and social responsibility. The cosmetic industry has stood out with approaches involving sustainable and innovative ingredients. In this context, inorganic nanoparticles, commonly composed of oxides (iron oxide), metals (silver and gold), or ceramides (silica), derived from industrial by-products of animal and plant origin, emerge as a promising proposal with benefits for both the product and the consumer, such as targeting and delivery to target cells. By incorporating these nanoparticles into cosmetic formulations, it is possible to explore various skin benefits, including protection against damage caused by UV rays, antimicrobial properties, and antioxidant effects, among others. Additionally, inorganic nanoparticles offer opportunities to enhance cosmetic products’ texture, stability, and efficacy, contributing to consumer satisfaction and loyalty.

The study conducted by Dey et al. (2022) addressed the sustainable extraction of metallic zinc oxide nanoparticles from T. glauca (Cav.) Kuntze leaves. They employed an aqueous extraction method by effusion at 60 °C for 15 min, followed by filtration and storage at low temperature to prevent degradation. The researchers also observed the presence of flavonoids, which imparted antioxidant properties to the species. This characteristic was previously identified and confirmed through analyses using DDPH (2,2-diphenyl-1-picrylhydrazyl), with quantification of absorbance readings in a UV spectrophotometer at 517 nm. The results revealed an average inhibition of 7.5%, demonstrating a dose-dependent relationship. Additionally, efficiency was observed at the highest test concentration (100 μg/mL), showing a 20.81% elimination of DPPH free radicals after 30 min of reaction. These findings indicate the potential of zinc oxide nanoparticles extracted from T. glauca (Cav.) Kuntze leaves as promising antioxidant agents [134].

Saratele et al. (2018) successfully synthesized silver nanoparticles using an aqueous extract of orange peel by adding an aqueous silver nitrate solution (AgNO₃, one mM). To optimize the synthesis, various physicochemical parameters such as pH, temperature, AgNO₃ concentration, and different ratios of extract/Ag mixture were evaluated and controlled to obtain the optimal conditions (room temperature; pH 4.5; AgNO₃ concentration, one mM; extract/AgNO₃ ratio, 1:5). With stability confirmed for up to 6 months, the inorganic silver metallic nanoparticles obtained demonstrate potential for application as antioxidants, antibacterial, and antitumor agents against C6 cells, exhibiting cytotoxicity at a rate of 50% at a mortality concentration of 60 μg/mL. Thus, this optimization strategy and applications transform the methodology into a promising and sustainable alternative [135].

Using the sol-gel method, Shim et al. (2018) synthesized and prepared silica nanoparticles from corn cob ash. Corn cob ash was dissolved in deionized water, filtered, and dissolved in NaOH solution. The resulting silica hydrogel was formed and dried to obtain corn cob silica (CCS) nanoparticles. Silver nanoparticles (Ag NPs) were embedded into the CCS by modifying the CCS surface with 3-APTES to produce amine-functionalized CCS (ACCS). ACCS was then mixed with AgNO₃ solution and distilled water, followed by reduction with NaBH4 to obtain ACCS-Ag NPs. The resulting nanoparticles were thoroughly washed and dried for further characterization and applications. After the elaboration of the nanoparticle, it was tested for bacterial activity, showing rapid inactivation of E. coli, suggesting the efficacy of bacterial control of the inorganic nanoparticle, thus demonstrating the great potential to integrate agricultural by-products into modern nanotechnologies [136].

Titanium dioxide (TiO₂) stands out among oxides as a polymorphic semiconductor with a wide intrinsic band gap in three mineral phases: anatase, rutile, and brookite. Specifically, in the cosmetic industry, especially in sunscreens, TiO₂ NPs are widely used due to their efficient capability to reflect and disperse ultraviolet B (UVB, 290–320 nm) and ultraviolet A (UVA, 320–400 nm) rays. In this context, Ramya et al. (2022) presented the synthesis of TiO₂ using eggshell residues processed for two days, followed by hot air oven treatment at 110 °C for 2 h. Eggshell dry powders (<25 μm) were obtained using a kitchen blender. In a 0.5 M titanium oxo solution, 10 mL of eggshell powder extract was added and mixed at 60 °C for 30 min. Then, a 1 M NaOH solution was gradually added to maintain the pH at 8. The eggshell powder was thoroughly washed with Milli Q water to remove excess NaOH. The product was then dried for 2 to 3 h, followed by calcination at 800 °C for 3 h to produce TiO₂ nanopowder formation. TiO₂ NPs were extensively characterized using UV-Vis, XRD, FT-IR, FE-SEM, and EDS techniques. The results concluded that the synthesized green TiO₂ NPs exhibit significant antimicrobial, anticancer, and photocatalytic activity, producing a new range of materials. The bio-reduction of metals will drive the development of a healthier approach [137].

Wary et al. (2022) synthesized zinc oxide NPs from aqueous solutions of ashes obtained from coconut shells, acting as a precipitating agent. Stock solutions were prepared at different pH levels (8.6, 10.4, and 12.7), free from toxic reagents. For commercial purposes, the inorganic NPs exhibit excellent photocatalytic activities in the degradation of methylene blue under solar irradiation. Additionally, a decrease in photocatalytic reactions was observed, and pseudo-first-order kinetics were considered [138].

Easmin et al. (2024) extracted and synthesized zinc NPs from papaya peel using the reducing power of EPI and ZnONPs with sustainable modifications regarding the concentrations of polluting reagents. They obtained promising results regarding antibacterial activities against human pathogens, with notable antioxidant potential in a 25–150 μg/mL concentration range and excellent photocatalytic activity [139].

Patra et al. (2021) obtained silver NPs from the extract of the outer husk by-product of dragon tongue beans. Dragon tongue bean pods (DtbP) were prepared by washing, draining, and cutting into pieces. The chopped pods (100 g) were boiled in 500 mL of DDH2O for 20 min, then cooled, filtered, and stored at 4 °C. For AgNP biosynthesis, 180 mL of 1 mM AgNO₃ solution was mixed with 20 mL of DtbP aqueous extract dropwise. The synthesized DtbP-AgNPs were confirmed by monitoring the solution color change over time. After 24 h, the solution was centrifuged, and the pellet was washed several times with DDH2O to remove unreacted DtbP extract. The pellets were then dehydrated (55 °C) for further analysis. The results of the biological activities showed remarkable cytotoxicity, anti-diabetic effects, and reasonable antioxidant activity [140].

The environmental impact of inorganic nanoparticles, particularly in terms of synthesis and disposal, can be mitigated through several strategies to reduce their ecological footprint. One effective approach is the implementation of green synthesis methods that utilize environmentally benign solvents and reagents, thereby minimizing hazardous waste production and energy consumption. For instance, as highlighted in the literature, adopting green chemistry principles in synthesizing nanomaterials can significantly lower environmental toxicity [141]. Also, proper lifecycle assessments (LCAs) are crucial for understanding and mitigating the environmental impacts of nanomaterials’ production, use, and disposal phases. These assessments help in identifying hotspots for environmental impact and guide improvements in the sustainability of nanomaterial production. Furthermore, regulatory frameworks that enforce strict disposal guidelines and promote the recycling of nanomaterials can also play a significant role in reducing their environmental impact. As noted by Levine (2020), policies such as the chemical bans implemented in Hawaii to protect coral reefs from harmful sunscreen ingredients demonstrate the importance of regulatory measures in safeguarding the environment from nanoparticle pollution [142]. By integrating these approaches, cosmetic companies can significantly mitigate the environmental impact of inorganic nanoparticles, ensuring safer and more sustainable practices.

Table 3. Composition, properties, and cosmetic performance of inorganic nanoparticles.

Type of Nanoparticle	Composition	Active Ingredient	Characterization	Physical-Chemical Properties	Formulation	Biological Performance	Reference
Metallic nanoparticle	Leaf extract; hexahydrated zinc nitrate 0.1	TiO2	X-ray diffraction	>50 nm	Thermally stable pure crystals	Antioxidant agents	[134]
Metallic nanoparticle	OPE-AgNPs	Ag	UV	15–20 nm	Aqueous solution	Bio-nanosynthesis, antitumoral, and microbial control	[135]
Inorganic nanoparticle	Corn aqueous extract- silver nanoparticle (ACCS-Ag NP)	ACCS	TEM	34.7 ± 8.6 nm ACCS; 5–10 nm Ag	Hydrogel	Bacterial inactivation	[136]
Metallic nanoparticle	Titanium oxo solution	TiO2	FE-SEM	30–40 nm	Nanocrystals	Antimicrobial; anticancer; and photocatalytic activity	[137]
Metallic nanoparticle	Aqueous solution	ZnO	SEM	9–14 NM	Nanocrystals	Photocatalytic activity	[138]
Metallic nanoparticle	Aqueous solution	ZnONPs	DLS, Zeta	170 nm; Zeta −21.0 mV	Crystals	Antibacterial activities; antioxidant	[139]
Metallic nanoparticle	Aqueous solution	DtbP-AgNPs	DLS, Zeta	78.02 nm; Zeta −33.3 mV		Biological activities showed remarkable cytotoxicity and anti-diabetic effects, along with reasonable antioxidant activity	[140]

Ag: silver, OPE-AgNPs: orange peel extract-silver nanoparticle, UV: ultraviolet, TEM: transmission electron microscopy, TiO₂: titanium dioxide, FE-SEM: field emission scanning electron microscopy, ZnO: zinc oxide, DLS: dynamic light scattering.

Table 3. Composition, properties, and cosmetic performance of inorganic nanoparticles.

Type of Nanoparticle	Composition	Active Ingredient	Characterization	Physical-Chemical Properties	Formulation	Biological Performance	Reference
Metallic nanoparticle	Leaf extract; hexahydrated zinc nitrate 0.1	TiO2	X-ray diffraction	>50 nm	Thermally stable pure crystals	Antioxidant agents	[134]
Metallic nanoparticle	OPE-AgNPs	Ag	UV	15–20 nm	Aqueous solution	Bio-nanosynthesis, antitumoral, and microbial control	[135]
Inorganic nanoparticle	Corn aqueous extract- silver nanoparticle (ACCS-Ag NP)	ACCS	TEM	34.7 ± 8.6 nm ACCS; 5–10 nm Ag	Hydrogel	Bacterial inactivation	[136]
Metallic nanoparticle	Titanium oxo solution	TiO2	FE-SEM	30–40 nm	Nanocrystals	Antimicrobial; anticancer; and photocatalytic activity	[137]
Metallic nanoparticle	Aqueous solution	ZnO	SEM	9–14 NM	Nanocrystals	Photocatalytic activity	[138]
Metallic nanoparticle	Aqueous solution	ZnONPs	DLS, Zeta	170 nm; Zeta −21.0 mV	Crystals	Antibacterial activities; antioxidant	[139]
Metallic nanoparticle	Aqueous solution	DtbP-AgNPs	DLS, Zeta	78.02 nm; Zeta −33.3 mV		Biological activities showed remarkable cytotoxicity and anti-diabetic effects, along with reasonable antioxidant activity	[140]

Ag: silver, OPE-AgNPs: orange peel extract-silver nanoparticle, UV: ultraviolet, TEM: transmission electron microscopy, TiO₂: titanium dioxide, FE-SEM: field emission scanning electron microscopy, ZnO: zinc oxide, DLS: dynamic light scattering.

5. Patents of Beauty Products Derived from Plant and Animal By-Products and Their Nanotechnological Aspects

According to patentometric data obtained by searching the Orbit Intelligence Platform between February and May 2024, there are around 2.370 patents for cosmetics and beauty field made up of active ingredients obtained from bio-inputs such as plant leaves, flowers and roots, algae, fish, and others. Searches were limited to active patents filed between 2020 and 2024 to analyze new market trends. To refine the searches, queries containing terms and codes were used, defined from terms such as expected effects combined with terms for the type of cosmetic and NPs, which refers to the central objective of the research (

Table 4. Comprehensive overview of active ingredients, characterization methods, and biological performance in recent skincare and pharmaceutical patents.

Document	Composition	Active Ingredient	Characterization	Physical-Chemical Properties	Formulation	Biological Performance
KR10-2534797	Anemarrhena asphodeloides extract polydeoxyribonucleotide, hyaluronic acid, collagen, glutathione, vitamin B2, menadione, thioctic acid, and vitamin C	PDRN	DLS, in vitro release and biocompatibility, moisturizing and anti-aging properties, in vivo anti-wrinkle activity, histological analysis and SOD activity.	143 nm. 40.9–5.3 mV	Skin lotions, skin toners, packs, nutritional creams	Moisturization, antioxidant, skin inflammation alleviation, skin barrier reinforcement, wrinkle improvement, and elasticity
KR10-2304048 B1	Neem oil, thyme oil, and geraniol oil, chitosan, PLGA, PLA	Matrine, phosphatidylcholine	LS13 320, absorption measurement, time absorption, in vitro permeation	145.8–227.7 n, 10.252 ppm	-	Antibacterial action, skin soothing effect, skin-whitening effect, anti-inflammatory
CN113730295 A	Sucrose stearate, sorbitan olivetoleate, polysorbate 20, laureth-23, polysorbate-80, isocetyl steareth-20, a mixture of glyceryl stearate and PEG-75 stearate, poloxamer 407, glyceryl stearate, ceteareth-25	Acetyl tetrapeptide-5, palmitoyl tripeptide-1 and palmitoyl tetrapeptide-7, and Ascophyllum nodosum extract	Safety test, test samples	-	-	Wrinkle-removing and tightening effects
WO2023/010188 A1	Water, Capric/Caprylic Acid, Triglyceride, Oleic acid, Linoleic acid, PPG-15 stearyl ether, Poloxamer, Steareth, Steareth-, Vitis vinifera extract1, Phenoxyethanol, Caprylyl glycol0, BHT, disodium EDTA, Sodium Metabisulfite	Anthocyanins, procyanidins, catechins, gallic acid, quercetin, kaempferol, myricetin and isoramnetin, caftaric acids, resveratrol	encapsulation efficiency, pH, skin permeation and antioxidant effect, nanozetasizer, Gene modulation assay	99.97%, 4.043–4.173, −30.9 mV	-	Antioxidant, anti-aging, anti-inflammatory, whitening effect, photoprotection, gene modulation activities
CN113616603 A	PEG, ethanol, DMSO	Naringenin, hyaluronic acid	DLS, thermal stability	140 nm	Facial masks, lotions or creams and the drugs are creams	Thermodynamic stability, nano-carrier, remove wrinkle, increase elasticity, prevent aging
EP4137125 A1	Glycerol stearate, cetyltrimethylammonium bromide, Tween 80	Algae lipids, oil from marine microalgae, lipids obtained from diatoms	DLS, PDI, zeta potential	100–300 nm, PDI ≤ 0.26, +40 mV	-	Nanocarrier, treatment of eczema, regenerative processes during skin
KR10-2617427 B1	Pine bark extract, phospholipids, ethanol, cholesterol, yolk lecithin (phosphatidylcholine), hydrogenatethyrestin, soy lecithin, lysolecithin, sphingomyelin, phosphatidylinositol, phosphatidic acid, phosphatidylethanolamine, phosphatidylserine, phosphatidylglycerol, phosphatidylinositol-4,5-diphosphoric acid, cardiolipin, and plasmarogen	Catechin, quercitrin	encapsulation rate, DLS cell 5oxicity 5est in vitro, skin moisturization increase rate, percutaneous moisture loss reduction rate	90%, 100 nm, 12,5 μg/mL, 7.05%, 7.48	-	Treatment of topical dermatitis, prevent itching and skin damage caused by skin inflammation, skin soothing, regenerating a skin barrier, skin itching, alleviating or preventing skin erythema
CN114159373 B	PBS, Dendrobium extract, tyrosine solution	Dendrobium nobile exosome vesicle	beta-galactosidase inhibition test of fibroblasts, type I collagen promotion assay for human fibroblasts, tyrosinase inhibition assay, test in vivo	0.5%, 11.2%, 18.3% and 35.2%	-	Anti-aging, whitening effects
CN114947107 B	Protein-chitosan, distilled water, acetic acid solution, corn oil	Globulin	deacetylation degree, optimum ultrasonic power, rheology, ionic strength stability, Zeta potential	≥90%, 100 s, 375 W	Pickering emulsion	Hydrophobicity, thermal stability and the ionic strength stability
CN113440453 A	Chinaberry extract, maltodextrin, coconut oil, corn oil, caprylic/capric triglyceride, grape seed oil, evening primrose oil, jojoba oil and olive oil, caprylic/capric triglyceride, squalane, glicerol, butanodiol, propilenoglicol, dipropilenoglicol, gliceril poliéter-7, gliceril poliéter-26, polietilenoglicol-400 e gliceril poliéter de glicose-20	Alpha-arbutin, hydrolyzed conchiolin	DLS	50–120 nm	Emulsion, cream and facial mask	Anti-inflammatory, repairing and whitening effect
CN116139062 A	Lotus flower, epsilon-polylysine, gamma-cyclodextrin and deionized water, epsilon-polylysine	Total flavonoids, proteins, vitamin C, fat, carbohydrate, carotene, thiamine, nicotinic acid	inhibition rate melanin synthesis	65%	-	Antioxidation, wrinkle resistance, moisture preservation, whitening, color spot fading, skin brightening, the like on skin, inhibition of melanin synthesis.

DLS: dynamic light scattering, SOD: superoxide dismutase, PLGA: poly(lactic-co-glycolic) acid, PLA: polylactic acid, PEG: polyethylene glycol, BHT: butylated hydroxytoluene, EDTA: ethylenediamine tetraacetic acid, DMSO: dimethyl sulfoxide, PDI: polydispersity index.

).

Searches of documents describing the skin moisturizing effect found around 979 documents containing processes for obtaining cosmetic formulations, including natural active ingredients. The document KR10-2534797 comprises a cosmetic composition with a moisturizing, repairing, anti-aging, skin barrier strengthening, elasticity improving, and anti-inflammatory action due to the concentration of phosphatidylcholine, sphingomyelin, phosphatidylserine, phosphoric acid, phosphatidyl ethanolamine, lectin, and polylactic acid extracted from Anemarrhena asphodeloides. The advantage of the invention consists of a preparation process containing hair extract, PDRN, and physiologically active substances with antioxidant activity, which promotes greater stability of the formulation and greater absorption by the skin [143]. Also noteworthy are technologies with formulations for skin treatment, such as invention patent KR10-2304048 B1, which refers to a cosmetic composition consisting of natural extracts of thyme oil, geraniol oil, and matrine as active ingredients, as well as PLGA NPs coated with chitosan. The document describes the process of preparing the active ingredient and the method of nanoencapsulation and characterization of the NPs. The invention provides the active ingredient as a biodegradable, antibacterial, bactericidal, and monoterpenoid chain, thus promoting a soothing and regenerative effect on the skin [144].

The research identified 1063 patents relating to products and processes with proposals for recovering or maintaining skin elasticity. Chinese patent CN113730295 presents an emulsion containing lipid NPs with skin repair activity, specifically wrinkles caused by aging. In addition, it contains active and acetyl tetrapeptide-5, 0.5–2% palmitoyl tripeptide-1 and palmitoyl tetrapeptide-7 and 0.4–2% Ascophyllum nodosum extract. The central claim of this invention is the process for preparing the lipid NPs and their excipients [145]. Document WO2023/010188 A1, on the other hand, is characterized by a cosmetic composition which, according to the claims, promotes improvement in skin elasticity and whitening, antioxidant action, prevention of aging, and photoprotection activity. The formulation contains, as ingredients, NPs of grape oil extract from the species Vitis vinífera L. This bioactive with has high concentrations of phenolic compounds, more specifically anthocyanins, flavonoids, procyanidins, catechins and gallic acid, quercetin, myricetin, resveratrol, coumaric acid, cephalic acid, caftaric acid, and resveratrol. These ingredients promote various benefits to the skin, especially protective, repairing, moisturizing, soothing and whitening effects. However, despite its many benefits, this active ingredient has low stability regarding its physicochemical properties [146].

Concerning technologies designed to prevent skin dehydration, we found 66 patents. The invention in patent EP4137125 A1 reveals the process for obtaining lipid NPs synthesized from marine microalgae oil and lipids of diatoms. The synthesis proposed by the inventors consists of preparing NPs using the HSH method, characterized by mixing at defined concentrations and subjected to different stirring speeds. This method is relevant because it produces 100–300 nm NPs, enables the product to permeate the skin with the desired active ingredient, and helps transport active substances such as vitamins and other chemical compounds [147]. In addition to these, documents with additional effects were also found, such as invention patent KR10-2617427 B1, which proposes the development of a dermo-cosmetic for the prevention and treatment of dermatitis and other skin diseases using pine bark extract. The NPs are synthesized from exosomes. This method is thought to promote better stability and efficacy of the active ingredient [148].

A further 671 patents were found with solutions for lightening or inhibiting the skin-darkening process. The document CN114159373 B describes a method for obtaining nanometric extracellular vesicles derived from Dendrobium for use in the preparation of cosmetic formulations for skin care, specifically those with anti-aging and whitening action due to their activity in promoting collagen synthesis, inhibition of elastin degradation, stimulation of hyaluronic acid production, and improvement in skin elasticity due to its inhibitory effect on tyrosine synthesis, inhibition of melanin transmission between melanocytes and keratinocytes, and reduction of melanin production. The phases of obtaining the vesicles consist of preparing the plant extract and the exosome vesicles [149]. Proposing a sustainable and low-cost solution, the patent CN114947107 B offers advantages such as stability, biocompatibility, and degradability, giving it great potential for formulations. The NPs are produced from proteins extracted from modified pea chitosan for application in a Pickering emulsion. This is characterized by its stability due to solid particles with high absorption in emulsified systems. The distinguishing feature of this product is that it is free of surfactants, such as emulsifiers, which are considered polluting waste. The invention also offers good stability, biocompatibility and degradability, giving it great potential for formulations. The aim is to present a solution for compositions with greater solubility and bioavailability [150]. In document CN113440453 A, the inventors propose a skin-whitening composition based on NPs containing Glycyrrhiza glabra root extract, an Asian plant which, in addition to its whitening activity due to its composition containing concentrations of alpha-arbutin, also has antibacterial, antifungal, antitumor, and antispasmodic properties. The active compound is encapsulated in cyclodextrin and has a size range of 50–120 nm. However, although widely used as a coating for solid and liquid particles with high efficiency, this molecule has low solubility in water. Hence, the invention adopts a second layer with a liposome wrapping to maintain the stability of the particle. Differentiated by NPs obtained from turnip anion polysaccharides, epsilon-polylysine, gamma-cyclodextrin, and deionized water using magnetic stirring, freezing, heating steps, and freeze-drying [151]. Chinese patent CN116139062 A discloses a cosmetic formulation containing NPs of lotus flower leaf extract rich in proteins, vitamin C, fat, carbohydrates, carotene, thiamine, nicotinic acid, and, more specifically, flavonoids that promote the effect of lightening spots with a melanin synthesis inhibition rate of 65%, as well as moisturizing and repairing wrinkles [152].

The survey data show that various solutions presented in the documents found propose the combination of more than one natural ingredient due to the synergistic effect obtained from this combination to promote one or more effects in the compositions, thus offering a differential with greater added value. Of the protected technologies, the most noteworthy are cosmetic forms presented as emulsions, creams, and gels for skin cleansing, skin moisturizing, wrinkle reduction, and skin whitening.

Another relevant fact is that China, the European Patent Organization, and South Korea are the countries with the most significant number of patents filed. These data corroborate that Jiangning University is the largest holder of patents. It can be inferred that research and solutions using NPs with natural inputs is a trend on the rise, with increasingly robust technologies to offer the consumer market products with reduced adverse effects, greater efficacy, and a view to sustainability principles.

6. Conclusions and Perspectives

This review emphasizes the pivotal role of nanotechnology in the cosmetic industry, particularly in advancing sustainable beauty through the valorization of plant and animal by-products. The innovative use of nanocarriers has shown significant potential in enhancing the delivery and efficacy of bioactive compounds derived from natural waste. In line with an eco-friendly ethos, these technology-driven approaches present substantial opportunities for the industry to meet consumer demand for green products. However, this progress is challenging, including technical hurdles, regulatory scrutiny, and the need for lifecycle assessments to ensure environmental safety. The complexity of manufacturing processes and the high research and development costs also pose economic challenges that must be addressed.

Nanomaterials and nanocarriers developed from plant and animal by-products offer numerous advantages. These include enhanced bioavailability and efficacy, as nanocarriers facilitate better penetration and controlled release of bioactive compounds. Using by-products also promotes environmental sustainability by reducing waste and promoting a circular economy, thus minimizing the ecological footprint of cosmetic production. Furthermore, these materials can be more cost-effective than synthetic alternatives, leveraging naturally abundant resources. Additionally, nanocarriers derived from natural sources are more biocompatible and safer for skin applications, reducing the risk of adverse reactions.

A collaborative approach is beneficial and essential to fully optimize the strategies for sustainable natural-derived cosmetic raw materials. We can maximize yield and preserve bioactive compounds by implementing advanced extraction techniques like supercritical fluid extraction, enzyme-assisted extraction, and ultrasonic-assisted extraction. Adhering to green chemistry principles ensures that our extraction and processing methods are environmentally friendly and sustainable. A crucial step is to develop standardized procedures for characterizing and guaranteeing the quality and consistency of raw materials derived from by-products. We can drive innovation and refine sustainable practices by fostering collaboration between academia, industry, and regulatory bodies.

The future of cosmetics, where natural by-products and nanotechnology converge, is promising, with several emerging trends and areas for investigation. One such trend is the development of personalized skincare solutions tailored to individual skin types and conditions using nanotechnology. Another is the innovation in intelligent delivery systems that release active ingredients in response to specific skin conditions or environmental factors. We also see advancements in biodegradable and eco-friendly packaging materials that reduce the overall environmental impact. However, it is crucial to establish comprehensive regulatory frameworks to ensure the safety and efficacy of nanotechnology-based cosmetics. Equally important is increasing consumer awareness and education about the benefits and safety of cosmetics derived from natural by-products and nanotechnology. By developing and adopting sustainability metrics to measure and report the environmental impact of cosmetic products, we can enhance transparency and accountability.

However, the progress in this field has its challenges. The scale-up of nanotechnology applications faces technical hurdles, regulatory scrutiny, and the need for lifecycle assessments to ensure environmental safety. Moreover, the complexity of manufacturing processes and the high costs associated with research and development pose economic challenges that must be navigated. As the industry moves forward, a focus on collaboration between scientific research, industry practices, and consumer education is vital. Opportunities lie in developing transparent supply chains, standardizing methods for characterizing NPs, and addressing the societal implications of using by-products. By embracing these challenges, the cosmetic industry can not only enhance the sustainability of its products but also contribute to a circular economy, ultimately benefiting both consumers and the environment.