PRP for hair loss: what the studies show in 2026

PRP for hair loss: how it works

A small blood sample is spun in a centrifuge to concentrate the platelets, blood cells that release growth factors. The plasma obtained is injected back into the scalp with fine needles, during the same session. The aim is to support weakened follicles, those producing ever finer hairs.

PRP has mainly been studied in androgenetic alopecia, the hormonal and hereditary hair loss that affects men and women alike. That is what this article is about. Temporary shedding after childbirth or an illness is a different situation, which I cover in another article.

What recent meta-analyses say

A meta-analysis pools the results of many trials to produce an average. In 2024, a review of 13 randomised trials found about 28 more hairs per square centimetre with PRP than with a placebo. In 2025, a broader review of 43 trials found a gain of the same order against placebo, about 28 hairs per square centimetre. Its authors work for a company that develops a PRP technique: this is worth knowing.

To put these figures in context: in an American randomised trial, participants started at about 150 hairs per square centimetre. The average gain is therefore real, but modest. It also varies a great deal from one study and one person to another. The 2024 authors rate the evidence as low quality: very heterogeneous trials and publication bias, meaning that disappointing studies are published less often.

That same American trial actually found no significant difference between the side of the scalp treated with PRP and the side treated with saline: density had increased on both sides. Its authors do not rule out that PRP spread from one side to the other, a limitation of this type of trial.

An add-on, not a treatment on its own

Compared directly with minoxidil, a standard treatment for androgenetic alopecia, PRP alone does no better in the three small trials pooled by the 2025 review. Added to a minoxidil lotion, it may bring an extra gain: about 18 hairs per square centimetre at five or six months in a review of five trials, with certainty rated very low. The 2025 review, for its part, found no significant benefit from this combination.

This is why I do not offer PRP as the only answer. It is considered after an assessment, alongside a suitable long-term treatment, not instead of it.

Who tends to respond more

An analysis of 25 trials looked at the factors associated with a more favourable result. PRP appeared more effective:

• in younger people;
• in women;
• when sessions were more numerous and closer together.

Expert recommendations advise it mainly for early to moderate stages, while the follicles are still present. At advanced stages, or when hair loss is long-standing, results are poorer; where the follicle has disappeared, PRP does not make hair grow back.

Judging at six months, and knowing when to stop

A hair grows about 0.3 mm a day, barely a centimetre a month. A result therefore cannot be judged within a few weeks. Trials usually measure density at around six months, and that is also when I review progress with you.

We then compare photographs taken in the same conditions, rather than an impression in the mirror. Without a measurable benefit, it is reasonable to stop the sessions: continuing would bring nothing.

How I approach it at the practice

Everything starts with an assessment: the history of the hair loss, an examination of the scalp, reference photographs and a targeted blood test, including iron and thyroid. Sometimes a simple, correctable cause makes PRP unnecessary.

When it is indicated, scalp PRP is offered at the practice from November 2026: three sessions one month apart, then maintenance if the result justifies it. It is not performed during pregnancy or breastfeeding, nor in case of a clotting disorder or a scalp infection.