The Effect of Tongkat Ali Supplementation on Body Composition in Exercise-Trained Males and Females

Abstract

Background: It has been suggested that supplementation with Tongkat Ali may affect testosterone concentrations; moreover, whether this influences body composition is unclear. Thus, the purpose of this investigation was to determine if four weeks of Tongkat Ali (400 mg daily dose) supplementation affected body composition and salivary free testosterone concentrations. Methods: Thirty-three exercise-trained males (n = 19) and females (n = 14) volunteered for this investigation (mean ± standard deviation: age 33.1 ± 13.0 years; height 171.1 ± 11.3 cm; body mass 77.4 ± 16.8 kg; average total years of training 13.9 ± 13.2; average hours of resistance training/week 4.2 ± 2.5; average hours of aerobic exercise/week 3.4 ± 2.8; average hours of other exercise/week 1.1 ± 2.0). Research participants were pre- and post-tested for body composition (InBody 270), Profile of Mood States (POMS), handgrip strength, and sleep (Pittsburgh Sleep Quality Index [PSQI]). In a subset of the research participants, saliva samples were collected and analyzed for cortisol and free testosterone. The research participants consumed 400 mg of Tongkat Ali or a placebo (rice flour) daily for four weeks. Results: There were no between-group differences (p > 0.05) for body composition (delta score, mean ± SD: lean body mass kg-treatment −0.5 ± 1.9, placebo −0.4 ± 0.7; fat mass kg-treatment −0.5 ± 1.6, placebo 0.3 ± 1.0, % fat treatment −0.1 ± 1.4, placebo 0.5 ± 1.1). Moreover, there were no differences between groups for any additional assessments (e.g., handgrip strength, mood, sleep, and salivary free testosterone and cortisol). Conclusions: Four weeks of supplementation with Tongkat Ali in exercise-trained males and females does not affect body composition, mood, sleep, vigilant attention, handgrip strength, cortisol, and free testosterone.

1. Introduction

Eurycoma longifolia Jack, commonly known as “Tongkat Ali”, is an herbal medicinal plant from Southeast Asia [1]. Traditionally, various parts of the plant have been purportedly utilized for their therapeutic properties, including antimalarial, aphrodisiac, anti-diabetic, antimicrobial, and anti-pyretic effects despite the dearth of scientific evidence [1]. Tongkat Ali has been purported to assist with erectile dysfunction [2], increase testosterone concentration [3], and improve mood [4]. To assess the effects of Tongkat Ali in aging males, scientists conducted a 6-month randomized, double-blind, placebo-controlled clinical trial involving 45 men (mean age: 47.38 ± 5.03 years) [5]. Both exercise training and Tongkat Ali supplementation showed improvements in erectile function, with the most significant enhancements observed in men undergoing concurrent training combined with Eurycoma longifolia supplementation [5]. In one of the few investigations that involved exercise training, Chen et al. examined the combined effects of a resistance training program and Eurycoma longifolia Jack on isokinetic muscular strength and power, anaerobic power, and urinary testosterone-to-epitestosterone (T/E) ratio in young males [6]. These investigators took 40 young males who were weight-matched and randomized to one of four groups: control (C), Eurycoma longifolia Jack (ELJ), resistance training (RT), and Eurycoma longifolia Jack plus resistance training (ELJ and RT). Participants in the ELJ and ELJ and RT groups consumed 200 mg of Eurycoma longifolia Jack daily, while those in the C and RT groups took placebo capsules daily for eight weeks. The resistance training program, consisting of 10 different exercises, was conducted thrice weekly for eight weeks. The resistance training program included ten stations featuring various exercises using elastic bands or dumbbells [6]. The exercises were heel raises with dumbbells, lateral raises with elastic bands, leg curls with elastic bands, bicep curls with dumbbells, leg abductions with elastic bands, front raises with dumbbells, knee extensions with elastic bands, arm extensions with dumbbells, half squats with elastic bands, and standing chest flies with dumbbells. Each exercise with dumbbells involved 10 repetitions, while those with elastic bands involved 15 repetitions. The dumbbells weighed between three and 12 kg, and the elastic bands were color-coded according to their elasticity. Participants rested for 1 min between stations and had a 3 min rest before starting a new set. They completed three sets of this circuit, and the program was conducted three times a week for eight weeks. It should be noted that these individuals were initially untrained. Isokinetic muscular strength and power, anaerobic power, and urinary T/E ratio were measured before and after the intervention [6]. After eight weeks of intervention, significant increases in the isokinetic average power of knee flexion at 300°/s were observed in the resistance training and combined ELJ and RT groups. In contrast, the control and ELJ-supplemented groups showed no changes in isokinetic muscular strength and average power from pre- to post-intervention. These findings indicate that resistance training enhanced lower limb power in participants. On the other hand, ELJ alone does not affect the training response.

Moreover, there have been no studies that have examined an exercise-trained population. More importantly, body composition has not been assessed. Indeed, if free testosterone (i.e., the biologically active form) is chronically elevated after the consumption of Tongkat Ali, one would expect a change in body composition. Thus, the purpose of this investigation was to determine if one month of Tongkat Ali supplementation affected indices of body composition, mood, sleep, physical performance, and salivary cortisol and testosterone concentration in exercise-trained males and females. The primary endpoints of this investigation were body composition and free testosterone concentrations.

2. Materials and Methods

2.1. Participants

Thirty-four individuals who regularly exercised (n = 34, 19 male, 15 female) volunteered for this randomized, double-blind, placebo-controlled trial. Individuals were considered “trained” if they had consistently exercised at least three times a week, incorporating activities such as aerobic or resistance training, over the past year. One female participant dropped out of the study without a reason, resulting in 33 subjects completing the investigation. All procedures involving human subjects were approved by the university’s Institutional Review Board (IRB# 2023_106 Concordia University), following the principles outlined in the Helsinki Declaration. Written informed consent was obtained from all participants before their involvement. Participants’ exercise history was evaluated through a questionnaire. Moreover, they were instructed not to change their exercise or dietary habits during the study.

2.2. Body Composition

Utilizing the InBody 270 (InBody, Cerritos, CA, USA), a bioelectrical impedance assessment device capable of measuring multiple frequencies, body composition metrics, including body mass, fat mass, lean body mass, body fat percentage, and total body water, were evaluated [7,8,9]. Participants were asked to fast three hours prior to the assessment. Standing on the device’s platform with bare feet on the electrodes, participants held handles equipped with additional electrodes on their thumb and fingers, maintaining straight arms and horizontally abducted at approximately 30 degrees. This assessment lasted approximately one minute.

2.3. Profile of Mood States

The Profile of Mood States (POMS) is a validated 65-word psychological test consisting of six mood scales designed for clinical evaluation. The Profile of Mood States (POMS) test is a psychological rating scale used to assess transient, distinct mood states. It measures six different dimensions of mood, which are:

• Tension: feelings of tension, nervousness, and apprehension.
• Depression: feelings of sadness, discouragement, and low morale.
• Anger: feelings of anger, irritability, and hostility.
• Vigor: feelings of energy, enthusiasm, and alertness.
• Fatigue: feelings of tiredness, weariness, and low energy.
• Confusion: feelings of confusion, uncertainty, and lack of clarity.

Participants responded to words such as “angry”, “tense”, and “lively” by selecting from a dropdown menu indicating their corresponding mood level, ranging from “not at all” to “extremely”. This tool assessed total mood disturbance, along with specific mood dimensions, including anger, depression, fatigue, tension, and vigor. The POMS test is widely used in both clinical and research settings to monitor mood changes in response to various interventions, treatments, or environmental factors [10,11]. It is valuable in understanding how different conditions affect emotional well-being and can be used to track changes in mood over time.

2.4. Psychomotor Vigilance (PVT) Test

The Psychomotor Vigilance Test (PVT) is a widely used behavioral measure of sustained attention and reaction time. It assesses an individual’s ability to maintain focus and respond quickly to visual stimuli over a period of time. Here are the key aspects of the PVT:

• Stimulus presentation: participants are asked to fixate on a screen where a visual stimulus (i.e., a number) appears at random intervals.
• Response: as soon as the stimulus appears, participants must tap the iPad or computer as quickly as possible.
• Duration: the test lasts five minutes.

The following data were accrued from the PVT.

• Reaction time (RT): The primary measure is the time it takes for a participant to respond (i.e., by tapping the iPad or computer) to the stimulus. This is usually recorded in milliseconds.
• False starts: Responses that occur before the stimulus are presented. That is, the subject taps the iPad or computer before a stimulus appears.

We used the Vigilance Buddy software (version 1.56) that is available on Apple devices. Detailed instructions were provided to ensure the correct execution of the test. This assessment has been used previously in our lab [12].

2.5. The Pittsburgh Sleep Quality Index (PSQI)

The PSQI consists of 19 items that generate seven components or subscales, each providing a score ranging from 0 to 3 [13]. The Pittsburgh Sleep Quality Index (PSQI) is a self-report questionnaire designed to measure sleep quality and disturbances over a one-month time period. It is widely used in both clinical and research settings to assess sleep patterns and identify potential sleep disorders. Here are the key components and features of the PSQI:

• Subjective sleep quality: an individual’s overall perception of their sleep quality.
• Sleep latency: the amount of time it takes to fall asleep.
• Sleep duration: the total amount of sleep obtained per night.
• Sleep efficiency: the ratio of total sleep time to time spent in bed.
• Sleep disturbances: factors that interrupt sleep, such as waking up in the middle of the night, bathroom trips, and other disruptions.
• Use of sleep medication: the frequency of medication use to aid sleep.
• Daytime dysfunction: the impact of poor sleep on daily functioning, including difficulty staying awake during the day and maintaining enthusiasm for daily activities.

The sum of these scores yields a global score ranging from 0 to 21, with higher scores indicating poorer sleep quality. The research participants completed the questionnaire based on their experiences over the past month, with responses indicating the frequency or severity of sleep-related issues. We noted the global score in our investigation.

2.6. Salivary Cortisol and Free Testosterone

In a subset of research participants, saliva samples were provided. Subjects provided saliva samples for cortisol and free testosterone quantification and DNA extraction via passive drool through a straw into a 1.5 mL micro-centrifuge tube immediately before and 5 min following the exercise tests. Saliva samples were run in duplicate and quantified via a human melatonin enzyme immunoassay (EIA) kit according to the manufacturer’s instructions (Salimetrics LLC, Carlsbad, CA, USA). The samples were immediately read in a BioTek ELx800 plate reader (BioTek Instruments, Inc., Winooski, VT, USA). All samples were within the detection ranges indicated in the immunoassay kit, and the variation in sample readings was within the expected limits. Cortisol and free testosterone concentrations were determined at baseline and post-exercise.

2.7. Statistics

Statistical analyses were conducted using GraphPad (Prism 10.2.3) statistical software. Data are presented as mean ± standard deviation (SD). Paired t-tests were used to compare the baseline vs. post-test scores for both groups. In addition, an unpaired t-test was used to compare the delta scores between groups. p < 0.05 was considered statistically significant.

3. Results

Nineteen male and fifteen female participants volunteered for this study. One female subject dropped out without a reason. The characteristics of the research participants are shown in

Table 1. Characteristics of the research participants.

	Tongkat Ali	Placebo	p-Value
Age, years	37 ± 14	30 ± 12	0.1127
Height, cm	174 ± 8	170 ± 14	0.3844
Total number of years of training	19 ± 15	9 ± 9	0.0177 *
Average hours of aerobic exercise/week	4 ± 3	3 ± 3	0.5244
Average hours of resistance training/week	4 ± 3	4 ± 3	0.6440
Other exercise hours/week	1 ± 2	1 ± 2	0.4224

The data are expressed as the mean ± SD. There were no significant differences between the groups except for the total number of years of training *. Tongkat Ali n = 16 (11 males and 5 females); placebo n = 17 (8 males, 9 females). Legend: cm—centimeters.

. There were no differences in baseline characteristics between groups except for the total number of years of training.

Tongkat Ali supplementation did not affect body composition (

Table 2. Body composition.

	Tongkat Ali			Placebo			p-Value Delta
	Pre	Post	Delta	Pre	Post	Delta
BM, kg	79.9 ± 13.1	78.9 ± 13.4	−1.0 ± 2.3	75.7 ± 19.6	75.6 ± 19.2	−0.1 ± 1.2	0.1585
LBM, kg	63.9 ± 12.0	63.4 ± 12.5	−0.5 ± 1.9	60.6 ± 15.5	60.2 ± 15.5 *	−0.4 ± 0.7	0.8218
Fat mass, kg	16.1 ± 5.2	15.5 ± 5.4	−0.5 ± 1.6	15.1 ± 8.8	15.3 ± 8.6	0.3 ± 1.0	0.0956
% Body fat	19.9 ± 5.6	19.8 ± 6.3	−0.1 ± 1.4	19.7 ± 7.6	20.2 ± 7.7 *	0.5 ± 1.1	0.2014
TBW, L	46.5 ± 9.0	46.4 ± 9.2	−0.1 ± 1.1	43.0 ± 12.3	42.5 ± 11.0	−0.5 ± 3.3	0.6969

The data are expressed as the mean ± SD. There were no differences in pre vs. post in the Tongkat Ali group (body mass p = 0.0921, LBM p = 0.3042, fat mass p = 0.1083, % fat p = 0.4882, TBW p = 0.4823). There was a significant difference in pre vs. post in the placebo group for * LBM (p = 0.0171) and * % body fat (p = 0.0333); however, there were no significant differences pre vs. post for fat mass (p = 0.1333) and total body water (p = 0.4643). There were no statistically significant differences in the delta score between groups for any of the assessments. Legend: BM—body mass, kg—kilograms, L—liters, LBM—lean body mass, TBW—total body water.

and Figure 1, Figure 2 and Figure 3), sleep, mood, or handgrip strength (

Table 3. Mood, sleep, handgrip strength.

	Tongkat Ali			Placebo			p-Value Delta
	Pre	Post	Delta	Pre	Post	Delta
TMDS	29 ± 39	11 ± 23	−18 ± 37	16 ± 23	6 ± 19	−10 ± 24	0.4744
PSQI	6.1 ± 2.1	5.5 ± 2.2	−0.6 ± 1.8	6.2 ± 2.5	5.5 ± 2.2	−0.6 ± 1.7	0.8886
Peak HG, kg	48 ± 9	48 ± 11	−1 ± 7	45 ± 15	45 ± 14	1 ± 2	0.5554

The data are expressed as the mean ± SD. There were no differences in pre vs. post in the Tongkat Ali group (TMDS p = 0.2182, PSQI p = 0.2424, HG p = 0.3952) or the placebo group (TMDS p = 0.1057, PSQI p = 0.0877), HG p = 0.1427). There were no significant differences between groups for the delta score. Legend: HG—handgrip, PSQI—Pittsburgh Sleep Quality Index, TMDS—total mood disturbance score.

), nor did it affect free testosterone or cortisol (

Table 4. Free testosterone and cortisol.

	Tongkat Ali
	Pre	Post	Delta
Free testosterone, pg/mL	247 ± 126	305 ± 180	58 ± 205
Cortisol, mcg/dL	0.206 ± 0.094	0.253 ± 0.167	0.047 ± 0.210
	Placebo
	Pre	Post	Delta
Free testosterone, pg/mL	283 ± 262	251 ± 172	−32 ± 309
Cortisol, mcg/dL	0.183 ± 0.033	0.225 ± 0.147	0.042 ± 0.162

The data are expressed as the mean ± SD. There were no significant differences in pre vs. post in the Tongkat Ali group (testosterone p = 0.1470, cortisol p = 0.1801) or the placebo group (testosterone p = 0.3973, cortisol p = 0.2439). There were no significant differences between groups for the delta score (testosterone p = 0.4266, cortisol p = 0.8692). Legend: Test—dL—deciliter; mcg—microgram; mL—milliliter; pg—picogram. Note: n = 15 (12 males, 3 females) for the Tongkat Ali group and n = 7 (3 males, 4 females) for the placebo group.

and Figure 4).

4. Discussion

The primary clinical endpoint of our investigation was body composition. Our investigation found that Tongkat Ali supplementation did not affect body composition (i.e., body mass, lean body mass, fat mass, percent body fat, and total body water) in exercise-trained males and females. This is the first investigation in trained males and females to show how Tongkat Ali supplementation affects body composition. The theoretical increase in lean body mass has been previously speculated due to the ostensible effect of Tongkat Ali supplementation on testosterone concentrations [3,14]. Nevertheless, our investigation showed that Tongkat Ali supplementation did not affect free testosterone or cortisol. Notably, virtually all studies on Tongkat Ali have been conducted on either clinical populations or untrained individuals. Interestingly, body composition is often neglected in these investigations. Zakaria et al. examined the short-term impact of Eurycoma longifolia Jack (ELJ) supplementation on muscle damage caused by eccentric exercise [15]. Eighteen well-trained rugby players (19–25 years) were randomized into one of two groups, ELJ and placebo (PLA). Each participant consumed four 100 mg capsules of the ELJ or placebo daily for seven days before performing a leg press eccentric exercise. Measurements taken included peak force, peak power, and jump height in countermovement jump (CMJ), drop jump reactive strength index (RSI), muscle soreness (using a 100 mm visual analogue scale), plasma creatine kinase (CK) activity, and salivary hormones at 24 h before and 0.5, 24, 48, 72, and 96 h after the exercise. These investigators found that the number of eccentric contractions performed was similar between the ELJ and PLA groups. Salivary testosterone and cortisol levels did not change significantly after supplementation in either group. In addition, there were no between-group differences in any of the other assessments. Thus, one week of ELJ (i.e., Tongkat Ali) supplementation did not affect hormones (i.e., testosterone and cortisol), performance, or skeletal muscle damage markers in the athletes [15].

Leitao et al. conducted a six-month treatment for androgen deficiency in aging males (ADAM) [5]. These investigators aimed to determine the effects of concurrent exercise training and Eurycoma longifolia supplementation on erectile function and testosterone levels in men with ADAM, as well as the relationship between erectile function and total testosterone levels. Twenty-two participants received a 200 mg supplement of Eurycoma longifolia, and twenty-three participated in concurrent training sessions three times a week for 60 min at progressive intensity. Both interventions improved erectile function, with the most significant improvements observed in the concurrent training + Eurycoma longifolia group. Thus, a 200 mg supplement of Eurycoma longifolia combined with concurrent training for 6 months significantly enhanced erectile function and increased total testosterone levels in men with ADAM [5].

Tambi et al. studied the effects of one month of 200 mg daily Tongkat Ali supplementation in hypogonadal males and demonstrated a significant increase in total testosterone [14]. In brief, 76 out of 320 patients with late-onset hypogonadism (LOH) were administered 200 mg of a standardized water-soluble extract of Tongkat Ali for one month. The Aging Males’ Symptoms (AMS) rating scale and serum testosterone concentration were measured. Results indicated that treatment with Tongkat Ali extracts significantly improved both the AMS score and serum testosterone levels. Prior to treatment, only 10.5% of patients had no complaints according to the AMS scale, and 35.5% had normal testosterone levels. After treatment, 71.7% of patients had no complaints, and 90.8% had normal testosterone levels. Therefore, Tongkat Ali extract seems to be effective as a supplement for alleviating symptoms of LOH and managing hypogonadism [14].

Henkel et al. examined 13 physically active male and 12 physically active female seniors (57–72 years) who consumed 400 mg of Tongkat Ali extract daily for five weeks [3]. Standard hematological parameters were measured, and the levels of total and free testosterone, dihydroepiandrosterone (DHEA), cortisol, insulin-like growth factor-1 (IGF-1), and sex hormone-binding globulin (SHBG) were analyzed. Additional biochemical parameters such as blood urea nitrogen (BUN) and creatine kinase (CK) were assessed to evaluate kidney function and muscle damage, respectively. Muscle strength was measured using a simple handgrip test. After the treatment, it was observed that hemoglobin, testosterone, DHEA concentrations, the total testosterone/cortisol ratio, and muscle force were significantly lower in female seniors compared to male seniors. In male seniors, hematocrit and erythrocyte counts increased slightly and were significantly higher than those in female seniors. The treatment led to significant increases in total and free testosterone concentrations and muscle strength in both men and women. The increase in free testosterone in women was attributed to a significant decrease in SHBG concentrations. Thus, in older adults, it was ostensible that Tongkat Ali supplementation may indeed elevate total and free testosterone as well as muscle strength [3]. The authors posited that the increase in free testosterone in women might be due to the significant decline in sex hormone-binding globulin concentrations [3]. Additionally, Talbott and colleagues investigated stress hormones and mood states in 63 participants (n = 32 males, n = 31 females) initially identified as being under moderate stress. Although not mentioned in that study, these subjects were likely sedentary. These individuals consumed 200 mg of Tongkat Ali or placebo daily for four weeks. The findings revealed a significantly improved stress hormone profile, indicated by reduced cortisol (−16%) and elevated testosterone levels (+37%) [4].

On the contrary, other studies have revealed no effect of Tongkat Ali on testosterone. Chinnappan et al. found no significant between-group differences in the free testosterone levels for two different doses of Tongkat Ali (100 and 200 mg daily for 12 weeks) compared to placebo [16]. In an investigation by Chan et al., 32 young males (24 years; 1.74 m; 73.7 kg) received 600 mg/day of Eurycoma longifolia (Tongkat Ali) or a placebo for two weeks [17,18]. On day 14, total testosterone was significantly greater in the treatment versus placebo group; however, free testosterone, the biologically active form of testosterone, was not significantly different between groups. Interestingly, this group also assessed the effects of Tongkat Ali after eight weeks of supplementation [18]. They found no differences between the Tongkat Ali and placebo groups regarding total and free testosterone. Ismail et al. examined the effects of 300 mg daily for 12 weeks of Tongkat Ali supplementation in a cohort of sedentary men (aged 30–55 years) [19]. They found no effect on body composition, nor did they find changes in total and free testosterone. Two investigations by the same laboratory group [6,20] provided further evidence that long-term supplementation with Tongkat Ali may not have any physiologically relevant effects. In a double-blind, placebo-controlled, crossover study, 13 healthy male recreational athletes were recruited [20]. During the first supplementation phase, they were instructed to take either 400 mg of Tongkat Ali or a placebo daily for six weeks. After a three-week washout, they were asked to take the other supplement for six weeks. They found no effect on the testosterone–epitestosterone ratio. Chen et al. [6] took 40 young males who were weight-matched and randomized into four groups: control (C), Tongkat Ali (TA), resistance training (RT), and Tongkat Ali combined with resistance training (TA-RT). Participants in the TA and TA-RT groups ingested 200 mg of TA daily, while those in the C and RT groups took placebo capsules daily for eight weeks. The resistance training program, comprising ten different exercises, was carried out three times a week for eight weeks. These investigators found that resistance training, with or without TA supplementation, enhanced the isokinetic power of the lower limb. In addition, the daily consumption of 200 mg of Tongkat Ali over eight weeks did not influence the urinary T/E ratio [6].

It seems apparent that if Tongkat Ali induces a meaningful physiologic effect, it would likely be in older hypogonadal males. Male hypogonadism is a clinical condition marked by reduced serum testosterone levels in men [21]. Leisegang et al. conducted a systematic review and meta-analysis of randomized clinical trials (RCTs) following PRISMA guidelines [21]. Relevant studies were sourced from PubMed, Scopus, Web of Science, Cochrane, Ovid/Embase, and Google Scholar databases. After screening the literature, nine studies were included in the systematic review, with five randomized controlled trials included in the meta-analysis. They reported a significant increase in total testosterone levels following E. longifolia treatment in both healthy volunteers and men with hypogonadism. The random-effects model indicated a significant increase in total testosterone levels in men receiving E. longifolia supplementation, confirmed in the hypogonadism subgroup. This particular systematic review and meta-analysis suggest that E. longifolia supplementation may enhance testosterone production.

Whether Tongkat Ali has a physiologically meaningful effect on free testosterone in young, exercise-trained men or women, is doubtful. The current investigation is the first to use well-trained subjects (i.e., over nine years of training experience; exercise training 8–10 h per week). In this cohort of exercise-trained males and females, four weeks of supplementing with 400 mg of Tongkat Ali had no meaningful effect on body composition and salivary free testosterone and cortisol. Furthermore, our investigation showed that Tongkat Ali supplementation did not affect mood (i.e., total mood disturbance score), sleep (i.e., Pittsburgh Sleep Quality Index), or handgrip strength. Regarding strength, there have been few investigations in this regard. Chen et al. found that in young males, resistance training combined with 200 mg/day for eight weeks of Tongkat Ali supplementation improved peak power output [6].

In Chen et al.’s study, forty young males were weight-matched and divided into four groups: control (C), Eurycoma longifolia Jack (ELJ), resistance training (RT), and Eurycoma longifolia Jack plus resistance training (ELJ and RT). Participants in the ELJ and ELJ and RT groups took 200 mg of Eurycoma longifolia Jack daily, while those in the C and RT groups took placebo capsules daily for 8 weeks. Resistance training alone increased relative anaerobic power, while the combination of Eurycoma longifolia Jack and resistance training improved peak power output. Moreover, consuming 200 mg per day of ELJ for 8 weeks did not affect the urinary T/E ratio. Other work showed that eight weeks of Tongkat Ali supplementation (600 mg/day) did not affect isokinetic strength or anaerobic power [18].

Work from Talbott and colleagues showed that Tongkat Ali supplementation for four weeks improved feelings of tension, anger, and confusion [4]. Moreover, Tongkat Ali boosts alertness when mice are active yet promotes sleep during their resting phases, suggesting its potential as a revitalizing remedy [22]. However, no human data exist to support an effect on sleep. Regarding physical performance, it is evident that strength training offsets the decline in muscle strength associated with aging in middle-aged women. Yet, Tongkat Ali supplementation does not increase muscle strength gains following a strength training regimen [23]. Conversely, supplementing with Tongkat Ali may enhance muscle strength in physically active elderly men and women [3]. Due to the scarcity of data, it is not possible to draw any conclusions regarding the influence of Tongkat Ali in exercise-trained men and women, particularly as it applies to mood, sleep, and physical performance.

Currently, only a few studies have examined the impact of Tongkat Ali as well as other purported testosterone boosters (TB) on serum testosterone levels [24]. Though several of these are randomized controlled trials (RCTs), they are often not conducted on athletes or an exercise-trained population. Additionally, there are limited data on the safety profile of these supplements. Therefore, more high-quality studies, such as RCTs, are needed to evaluate the effects of Tongkat Ali on serum testosterone levels in healthy adults.

5. Conclusions

The strength of our investigation is the fact that our research participants were healthy, exercise-trained men and women. One of our limitations was the treatment duration of four weeks. Future research should examine young, healthy, exercise-trained men and women as separate cohorts. Furthermore, it would be interesting to see if body composition is affected when a novel exercise training program is combined with Tongkat Ali. Nonetheless, based on our limited cohort, four weeks of supplementing with 400 mg of Tongkat Ali in young exercise-trained men and women did not affect body composition, cortisol, free testosterone, sleep, mood, or strength.