The Efficacy of Growth Factor Injection in Androgenic Alopecia: A Systematic Review and Meta-Analysis.

BACKGROUND

Androgenetic alopecia (AGA) is the most common cause of hair loss, and current pharmacotherapies have limitations. Autologous platelet-derived therapies, including PRP, its standardized derivative PRGF, and other growth factor concentrates (GFC), have emerged as regenerative options, but differences in preparation and mixed clinical evidence remain.

METHODOLOGY: Following PRISMA guidelines, seven databases were searched for randomized and non-randomized studies on intralesional growth factor injections for AGA. Outcomes included hair density, thickness, satisfaction, and adverse events, with quality assessed using RoB2, MINORS, and MMS tools.

RESULTS

Twelve studies (745 patients) were included. GFC showed progressive hair density gains from 19.6 hairs/cm2 at 1 month to 57.1 at 12 months, while PRP increased density by 34.4 at 6 months and 42.0 at 12 months. GFC also improved thickness (5.19-22.03 µm) with 94.3% patient satisfaction. Adverse events were mild, but RCTs had a high risk of bias, and non-randomized studies showed serious to critical bias.

CONCLUSION

Autologous growth factor injections appear safe and improve hair density, thickness, and patient satisfaction over 12 months, especially with newer concentrates. However, high risk of bias, substantial heterogeneity (I2 > 90%), and non-standardized protocols limit the evidence, making findings hypothesis-generating until larger, standardized, double-blind trials with long-term follow-up are conducted.

LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors   www.springer.com/00266 .