💡 Quick answer
The landmark clinical studies, treatment history and latest research for PRP — fact-checked and sourced.
Research & evidence
How treatment evolved
2006Uebel et al. publish the first controlled use of platelet-rich plasma in androgenetic alopecia hair-transplant surgery, soaking follicular-unit grafts in PRP and reporting roughly a 15% higher follicular-unit yield/density on the PRP-treated side (Plast Reconstr Surg, vol. 118).
2014Period of rapid expansion of small open-label, observational and pilot PRP studies for AGA (e.g., Schiavone et al.; Khatu et al.), establishing the typical injection protocol (about 3 monthly sessions) later used in controlled trials and review articles.
2015Gentile et al. publish a widely cited randomized, placebo-controlled, half-head trial of injectable PRP for male AGA (Stem Cells Transl Med, 4(11):1317-1323), reporting significant hair-count/density gains over placebo after 3 sessions at 30-day intervals.
2016Alves & Grimalt publish a randomized, double-blind, placebo-controlled, half-head trial (Dermatologic Surgery, 42:491-497), confirming a positive PRP effect and framing PRP as an adjuvant therapy for AGA.
2018European S3 evidence-based guidelines on androgenetic alopecia classify PRP at evidence level 3 for both male AGA and female pattern hair loss, reflecting promising but low-quality/heterogeneous evidence.
2024PRP for AGA remains FDA-unapproved and off-label; PRP is an autologous blood product (preparation kits/centrifuges are 510(k)-cleared devices, but PRP itself is not FDA-approved as a labeled hair-loss treatment), so it is used off-label despite multiple positive trials.
Key clinical studies
Gentile et al., 20152015
Randomized, placebo-controlled, evaluator-blinded half-head trial; 23 men enrolled, 20 completed; 3 PRP sessions at 30-day intervals; followed up to 2 years
At 3 months the PRP-treated scalp half gained a mean of ~45.9 hairs/cm2 versus a ~3.8 hairs/cm2 decrease on the placebo half (and ~33.6 more hairs in the target area vs placebo), differences reported as statistically significant (p<.0001); 4 of 20 needed retreatment by ~12 months.
Stem Cells Translational Medicine 2015;4(11):1317-1323
Alves & Grimalt, 20162016
Randomized, double-blind, placebo-controlled, half-head study; 25 patients with AGA; 3 PRP injection sessions 1 month apart
Six months after the first session, the PRP side showed significant increases over baseline in mean anagen hairs, hair density (~179.9) and terminal hair density (~165.8) (p<.05); authors conclude PRP has a positive effect and can serve as an adjuvant therapy for AGA.
Dermatologic Surgery 2016;42(4):491-497
Latest research: Recent work (2023-2026) has shifted from asking whether PRP works to standardizing it and combining it: studies and network meta-analyses increasingly test PRP alongside minoxidil, microneedling, and growth factors (e.g., PRP plus basic fibroblast growth factor ranking highly for added hair-density gains), while reviews emphasize the need for standardized PRP preparation/dosing protocols and position newer regenerative options such as exosomes and stem-cell-derived therapies as the next frontier.
Summaries reflect published, peer-reviewed research and are not medical advice. See the linked sources for details.
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Not medical advice. General education only; it does not replace diagnosis or treatment by a licensed professional. Consult a board-certified dermatologist before starting, stopping or changing any treatment.
⚠️ When to see a doctor — don’t self-treat
- Sudden patchy or circular bald spots
- Redness, scaling, pus, pain or itch (possible scarring alopecia — treat urgently)
- Broken hairs or rapid loss
- Loss with body-wide signs (weight loss, fatigue, cycle changes, acne, extra hair)
- Loss right after a new medication
- Any hair loss in a child