*Article* **Effectiveness of Platelet-Rich Plasma Therapy in Androgenic Alopecia—A Meta-Analysis**

**Simona Roxana Georgescu 1,2 , Andreea Amuzescu 2, \*, Cristina Iulia Mitran 3 , Madalina Irina Mitran 3 , Clara Matei <sup>1</sup> , Carolina Constantin 4,5 , Mircea Tampa 1, \* and Monica Neagu 4,5,6**


**Abstract:** Platelet-rich plasma (PRP) represents a novel therapy tested and is used more and more frequently in dermatology and cosmetic surgery for a variety of conditions, including androgenic alopecia (AGA), a common condition with a complex pathogenesis involving genetic factors, hormonal status and inflammation. We performed an extensive literature search which retrieved 15 clinical trials concerning the use in AGA of PRP therapy, alone or in combination, in male, female or mixed patient groups. A quantitative statistical meta-analysis of *n* = 17 trial groups proved significant increases in hair density from 141.9 ± 108.2 to 177.5 ± 129.7 hairs/cm<sup>2</sup> (mean ± SD) following PRP (*p* = 0.0004). To the best of our knowledge, this is the first meta-analysis that proved a statistically significant correlation between the number of PRP treatments per month and the percentage change in hair density (*r* = 0.5, *p* = 0.03), as well as a negative correlation between the mean age of treatment group and the percentage change in hair density (*r* = −0.56, *p* = 0.016). Other factors considered for analysis were the PRP preparation method, amount used per treatment, hair diameter, terminal hairs and pull test. We conclude that PRP represents a valuable and effective therapy for AGA in both males and females if patients are rigorously selected.

**Keywords:** androgenic alopecia; clinical trial; hair density; inflammation; meta-analysis; plateletrich plasma
