Placebo-controlled trials provide evidence that PRP can improve hair density in androgenetic alopecia, but results vary considerably. Evidence of an average benefit does not establish that everyone responds, that every clinic protocol is equivalent or that PRP is the best first treatment for you.
Evidence checked 1 November 2026. Prepared by The Wellness Team.
Why does a placebo comparison matter?
A placebo group helps distinguish the effect of treatment from changes that happen over time, measurement variation and the context of receiving care. In hair studies, photographs before and after treatment cannot answer that question alone.
Some trials use a split-scalp design, comparing treated and control areas within the same person; others compare groups. Each design has strengths and limitations. Ask whether a claim is based on a controlled trial, an uncontrolled case series or a clinic testimonial.
What did the 2025 review find?
A 2025 systematic review included 43 randomised controlled trials with 1877 participants across alopecia outcomes. Its hair-density analysis showed improvement with PRP compared with placebo, but there was substantial variation between studies.
The review found no statistically significant overall benefit for hair thickness. Density and thickness describe different things, so a density finding should not be rewritten as proof that every hair becomes thicker. A statistically significant group result also does not tell you what change will be visible to you.
Does this mean every type of hair loss should receive PRP?
No. Most of the included research concerned androgenetic alopecia. The review included far fewer trials for other diagnoses, including only one involving chronic telogen effluvium. Results should not be transferred freely between conditions.
Scarring, inflammatory and sudden diffuse hair loss need an appropriate diagnostic pathway. A treatment can have evidence for one condition and still be the wrong next step for another. A consultation that says PRP is unsuitable can prevent an expensive course with little prospect of benefit.
Is PRP better than established treatment?
A placebo advantage is not the same as superiority over an active treatment. In the review, comparisons with active treatments did not establish a consistent density advantage for PRP. Small comparisons and wide uncertainty do not prove that treatments are equivalent either.
The decision should consider the diagnosis, your previous treatment, tolerability, preferences, practical burden and cost. Do not stop prescribed treatment because an injection is presented as more advanced or natural.
Why do clinic results vary?
Preparation, administration, study populations, follow-up and measurement methods differ. Reporting of PRP composition was incomplete in the review, which limits confident conclusions about which technical variation produces the best result.
A claim that one centrifuge, activation label or platelet multiple guarantees superiority needs direct clinical evidence. Scientific-sounding detail can explain a process, but it is not a substitute for trials showing a meaningful patient outcome.
How should I decide whether a course is worthwhile?
Agree what success would mean before starting and when it will be assessed. Ask about baseline photographs, realistic uncertainty, adverse effects, alternatives, follow-up and what happens if no useful change is seen.
Pain, tenderness, bruising and other adverse effects were reported in the studies. PRP uses your own blood, but that does not remove procedural risks or the need for sterile technique and consent. A course should be a considered choice, not a commitment driven by a guaranteed-results headline.
What should a premium clinic explain?
It should connect the evidence to your diagnosis without promising that a study average will become your result. It should also explain the total proposed course, review arrangements and any later decisions about maintenance.
Ask The London PRP Clinic for an individual assessment Bring previous photographs and a record of treatment. Paying for a clear diagnosis and an honest plan is more valuable than paying for certainty that the evidence cannot support.
Sources and evidence limits
- 2025 systematic review and meta-analysis of PRP for alopecia
- Clinical and Experimental Dermatology: standardising hair-loss photography
This guide explains evidence and questions for a consultation. It does not diagnose your condition or confirm that a test or procedure is appropriate for you.
What should I do next?
Discuss an individual assessment with The Wellness. Bring your previous results, medicines and the question you want answered. Ask for a written plan and quote before deciding to proceed.