Platelet-rich plasma (PRP) for hair loss

Key takeaways

• Pooled data are positive but low quality. A 2024 meta-analysis of 13 randomized trials (431 people) found about 27.5 more hairs per cm2 than placebo but no significant change in hair diameter. Heterogeneity was extreme (I2 of 96%) and publication bias was evident (Kieling 2024). Other meta-analyses agree on density (Zhang 2023; Papakonstantinou 2023; Evans 2022).
• Several well-designed trials were negative. In a 35-person split-scalp trial both sides gained about 16 to 20 hairs per cm2 with no difference between them (Shapiro 2020). Thirty men given 5 sessions saw no improvement (Gressenberger 2020), and trials in women and in advanced male loss were also null (Puig 2016; Mapar 2016).
• The split-scalp design may hide the effect, because PRP probably spreads to the placebo half. Placebo halves kept about 37 hairs per cm2 more than placebo groups in whole-head trials (Gupta 2022).
• Protocol seems to matter. Three monthly sessions plus a 3-month booster gave about 30% more hair against about 7% for two sessions three months apart (Hausauer 2018). Across 25 trials, more sessions, shorter intervals, activation, double centrifugation, younger age and female sex were linked to better results (Gupta 2022 NMA).
• There is no standard product. Only 21% of trials reported all preparation variables (Kramer 2018), and platelet count did not predict response (Rodrigues 2019).
• It is not better than minoxidil, but may add to it. Nine head-to-head trials against 5% minoxidil found no density difference (Umar 2026). Added to minoxidil, PRP gave about 18 more hairs per cm2 at 5 to 6 months, with low to very low certainty (Yao 2024).
• Results fade without maintenance. In one trial 4 of 20 men had progressive loss 12 to 16 months after treatment and were retreated (Gentile 2015).

What it is

Whole blood is spun in a centrifuge once or twice to concentrate platelets. Some clinics activate the PRP with calcium or thrombin, then inject it into the thinning scalp. Platelets release growth factors such as PDGF, VEGF and EGF, which might prolong the growth phase and improve blood supply around follicles. Growth-factor content varies widely between patients and sessions. In the US PRP is treated as minimally manipulated autologous tissue, so no PRP product has an FDA hair-loss indication.

What the studies show

• Gentile 2015, 20 men analysed, 3 sessions 30 days apart: +45.9 hairs per cm2 from baseline in a half-head design (Gentile 2015).
• Rodrigues 2019, 26 men, 4 injections: higher count, density and share of growing hairs, with no link to platelet count (Rodrigues 2019).
• Dubin 2020, 30 women, sessions at weeks 0, 4 and 8: 57% vs 7% improved on photos, and hair counts moved +106 vs -52 per cm2. A 52-hair loss in the placebo group suggests measurement noise, so do not take the size of the effect at face value (Dubin 2020).
• Shapiro 2020 and Gressenberger 2020: no benefit over placebo (see above).
• Umbrella review: at least 0.05 mL per cm2 (preferably 0.1) and at least 3 monthly sessions were suggested (Li 2023).
• Guidelines are split. The European S3 guideline (2017) made no recommendation for or against PRP, citing no standard technique, while a 2025 Canadian consensus recommends it (Landells 2025).
• Breast cancer survivors, 27 patients, split-scalp pilot: both sides gained density with no difference between them, and circulating tumour cells were found in the PRP in 2 of 12 assays, with no tumour seeding seen. Cancer survivors should involve their oncologist (Rossi 2026).

How it's used in studies

Trials typically gave 3 monthly sessions, then maintenance every 3 to 6 months, and judged results at about 6 months. It is aimed at early pattern loss with miniaturized but living follicles; Norwood 4 to 6 was null in one trial. Microneedling does not appear to carry growth factors deep into the skin, so topical PRP after needling is not equivalent to injection (Dhurat 2019). If you consider PRP, ask the clinic about single or double spin, activation, volume per cm2 and platelet concentration.

Side effects and safety

• Pain, headache, scalp tightness, swelling, redness and pinpoint bleeding are common and short-lived (Dubin 2020).
• A single 2025 case report described reversible vision loss a month after scalp PRP in a young woman. Causation is unproven (Bibi 2025).
• Bleeding disorders, anticoagulant use, active scalp infection and autoimmune disease are reasons to avoid it (Nestor 2021).
• Cost is about $100 to $1,000 a month on one review's scale, and $5,000 to $15,000 over 5 years, usually not covered by insurance (Nestor 2021).

Bottom line

PRP is a possible add-on with a modest and uncertain benefit, not a replacement for minoxidil or finasteride. It makes most sense as a later rung for early loss in people who are already on proven treatment, and it needs ongoing sessions. See the treatment ladder. Discuss with a doctor.