Platelet-rich plasma (PRP) therapy for hair loss involves drawing a small amount of the patient’s own blood, processing it to concentrate the platelet-containing plasma, and injecting this concentrated solution into the scalp. The rationale is that platelets release growth factors that stimulate follicle activity. Here is an honest assessment of where the evidence stands.
The biological mechanism is plausible. Platelets release growth factors including PDGF, VEGF, and EGF, which have been shown in laboratory settings to stimulate follicle cell proliferation and extend the anagen phase. The mechanism behind PRP’s theoretical benefit in androgenetic alopecia is better established than that of many other treatments.
The clinical evidence is more mixed. Multiple randomised controlled trials have shown statistically significant improvements in hair density and thickness with PRP compared to placebo. However, effect sizes are variable across studies, the optimal preparation protocol (concentration of platelets, number of sessions, injection depth) has not been standardised, and no trial has followed patients for longer than twelve months to determine whether the benefit is sustained.
What PRP consistently does not do is halt androgenetic hair loss permanently in the same way that finasteride does. It appears to provide a boost to follicle activity, but this boost diminishes over time without repeated sessions. PRP is therefore most appropriately considered as a maintenance adjunct to medical therapy, rather than a standalone treatment.
For patients considering PRP as part of a post-transplant regimen, the timing and evidence for PRP to improve graft survival are interesting but not yet robust enough to be considered standard practice.
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