PRP for hair loss: promising, unstandardised, and not a replacement for anything

Platelet-rich plasma is your own blood, drawn, spun in a centrifuge to concentrate the platelet fraction, and injected into the scalp. The proposed mechanism is that platelet growth factors — PDGF, VEGF, IGF-1 among them — prolong the growing anagen phase of the hair cycle.

It is one of the few hair treatments where the fair summary genuinely sits between the two camps. The evidence is better than the sceptics allow. It is also far less useful to an individual than the clinics quoting it imply, and for a reason that is easy to state and hard to get around.

What the best evidence says

The strongest single source is a systematic review and meta-analysis published in Dermatology and Therapy in 2025, online on 13 September 2025 ^[1]. It included 43 randomised controlled trials, with 41 in the quantitative synthesis and 1,877 participants, around 73% of them male, and used the RoB 2 tool to assess risk of bias.

Its conclusion, stated in its own words: “moderate evidence… PRP is safe and effective in improving hair density” ^[1].

Two sub-findings are worth carrying forward. Activated PRP outperformed placebo, and non-activated PRP was associated with more adverse effects ^[1]. A 2024 review in the Journal of Cosmetic Dermatology reached a similar conclusion with similar caveats ^[2].

That is a genuinely positive body of evidence by the standards of cosmetic dermatology, and it deserves to be reported as such rather than dismissed.

The limitation the authors named themselves

Here is the sentence that should shape how you use the finding above. The review’s own stated limitation was that heterogeneity in study designs and incomplete reporting of PRP composition prevented meaningful subtype analysis ^[1].

In other words: the trials worked, on average, but the review could not determine which PRP worked, because the trials mostly did not report what they had made.

There is no standard PRP

Quantify the variation and the problem becomes obvious. Trials differ on ^[1]:

• spin protocol and g-force, and whether one spin or two
• final platelet concentration, which is rarely reported at all
• leucocyte-rich versus leucocyte-poor preparations
• activation with calcium chloride or thrombin, versus no activation
• injection depth and volume
• number of sessions — commonly three or four
• interval between sessions — anywhere from two to six weeks
• maintenance frequency thereafter

Every one of those is a variable that could plausibly change the biology. A leucocyte-rich, unactivated, single-spin preparation injected at one depth every six weeks is not the same intervention as a leucocyte-poor, calcium-activated, double-spin preparation injected at another depth every two weeks. They share a name and an acronym.

The practical consequence: two clinics’ “PRP” are not the same intervention, so a pooled estimate from 41 trials is of limited use in predicting what one particular clinic will achieve for one particular person. That is not a reason to dismiss PRP. It is a reason to be sceptical of any clinic that quotes a pooled effect size as though it applied to their protocol.

The other weaknesses, stated plainly

Beyond heterogeneity, the literature has the problems you would expect of a commercially driven field ^{[1, 2]}:

• small samples in most individual trials
• short follow-up, mostly six months or less, so durability is essentially unstudied
• many half-head designs, where one side of the scalp is treated and the other is control — elegant, but vulnerable to systemic effects and to unblinding
• inconsistent outcome measures between trials
• substantial commercial interest from kit manufacturers, with many studies manufacturer-supported or built around a single proprietary system
• publication bias is likely, as it is in any field where positive results sell equipment

Where UK regulation sits

PRP for hair loss is not a licensed medicine in the UK. There is no MHRA marketing authorisation, no NICE technology appraisal, and no Clinical Knowledge Summaries recommendation for it in androgenetic alopecia ^{[3, 4]}.

The reason is structural rather than a judgement on the evidence. PRP is delivered as an autologous, minimally manipulated blood product prepared at the point of care — your own blood, spun and returned to you — which sits outside the medicines licensing framework. What is regulated are the kits and centrifuges, as UKCA or CE-marked medical devices ^[3]. A clinic can honestly say its equipment is regulated. That is a statement about a centrifuge, not about a treatment.

It is not available on the NHS for hair loss ^[4].

What it costs

UK clinics typically advertise £400 to £900 per session, with three or four initial sessions and maintenance every four to six months. That commonly works out at an advertised £1,500 to £3,000 in the first year, followed by an open-ended ongoing commitment.

Treat those as advertised prices rather than surveyed figures — nobody has systematically surveyed what UK patients actually pay, and the range is wide. The more important number is the one nobody advertises: this is a recurring cost with no endpoint, because stopping returns the scalp to its untreated trajectory. Our guide to what private treatment costs in the UK covers how to compare that against alternatives.

An honest position

Pulling it together:

• The direction of effect is consistently positive across a reasonable number of randomised trials.
• The safety profile is good — it is autologous, and the adverse events reported are mild and transient pain, swelling and tenderness at the injection sites.
• The effect sizes are modest.
• The intervention is unstandardised, so the evidence does not transfer cleanly to any specific clinic.
• Comparisons against licensed treatments are few, so we do not know how it stacks up against the options that do have a UK licence.
• Durability beyond six to twelve months is essentially unstudied.

Promising but not established is the accurate description. PRP is reasonable as an adjunct for someone already on a licensed treatment who wants to do more, and it is not a substitute for a licensed treatment — topical minoxidil is a pharmacy medicine with a UK licence for pattern hair loss, and choosing an unlicensed injection instead of it is a decision worth examining. Our guide to minoxidil explained covers that baseline.

If you are weighing PRP against other adjuncts, microneedling for hair loss and laser caps for hair loss sit in the same category of modest evidence and private cost, and hair transplants in the UK covers the one intervention that moves follicles rather than trying to revive them.

This article is for general information and isn’t a substitute for advice from your own clinician. If you feel unwell, contact your GP or NHS 111. In an emergency, call 999.