PRP and polynucleotides — the better-studied end of the category

These two are grouped with stem cells and exosomes by marketing, and separated from them by evidence. PRP for androgenetic alopecia has multiple independent meta-analyses of randomised controlled trials showing increased hair density against placebo, with the largest of them grading that evidence low certainty under GRADE. PDRN has a substantial pharmacology literature describing an adenosine A2A-receptor mechanism and use in impaired wound healing, and polynucleotides in aesthetic use have one systematic review of nine mostly small studies. Neither is proven; both have been tested in people in ways most of this category has not.

Platelet-rich plasma

What it is

Blood is drawn from the patient and centrifuged so that platelets concentrate into a small volume of plasma, which is then injected. Platelets are anucleate cell fragments that release growth factors when activated. PRP contains no stem cells, and describing it as a stem cell treatment is simply an error of fact.

Preparation is not standardised. Studies differ in whether the platelets are activated, in centrifugation protocol, in final platelet concentration and in injection schedule — a heterogeneity the systematic reviewers name explicitly as a limit on pooling results^[1]. Two clinics offering “PRP” may be delivering measurably different preparations.

What the trials found

The most comprehensive synthesis identified 27 controlled trials covering 1,117 subjects across androgenetic alopecia and alopecia areata. Against saline injection, PRP increased hair density over medium-term follow-up by a mean difference of about 25.6 hairs per square centimetre. The reviewers rated that evidence low quality under GRADE, citing inconsistency and risk of bias, and reported no serious adverse events in either arm^[1].

A meta-analysis restricted to nine randomised controlled trials in 238 patients with androgenetic alopecia found statistically significant increases in hair density against placebo at three and six months; hair count and hair diameter improved relative to baseline but not significantly relative to placebo^[2]. In female pattern hair loss specifically, a meta-analysis of seven studies found increased terminal hair density without a significant increase in hair thickness, and its authors recommended caution pending replication in larger and more representative samples^[3].

How to read that

Consistently: density improves, other measures are less consistent, and the reviewers decline to overstate it. It is also worth keeping the comparator in view. Reviews of androgenetic alopecia treatment identify topical minoxidil, oral finasteride and low-level light therapy as the FDA-approved options, with PRP among the alternatives that lack that status^[4]. A discussion that reaches PRP without having addressed the approved options has skipped a step.

The parent clinic that publishes this site maintains a clinical page on PRP with more procedural detail. It is linked here for completeness rather than as a recommendation; the evidence summary above is the same either way.

PDRN and polynucleotides

What they are

PDRN — polydeoxyribonucleotide — is a mixture of deoxyribonucleotides with molecular weights in a defined range, produced from salmon DNA through a controlled purification and sterilisation process designed to eliminate active protein and peptide content that could provoke an immune reaction. Its proposed mechanism is engagement of the adenosine A2A receptor, together with supply of nucleosides and nucleotides to the salvage pathway^[5]. A review of its application in skin regeneration describes effects on cell migration, angiogenesis and inflammation across in vitro, in vivo and clinical wound-healing studies^[6].

“Polynucleotide” is the broader term now widely used in aesthetic practice. It is important not to assume PDRN’s pharmacology transfers wholesale to every product marketed under the polynucleotide label: the mechanistic literature was built on PDRN specifically, and source material, molecular weight distribution and manufacturing differ between products.

What the aesthetic evidence shows

A systematic review published in 2024 identified nine studies of low and moderate quality covering 219 patients receiving polynucleotide treatment. It reported promising outcomes in reducing wrinkles, improving skin texture and enhancing elasticity, with statistically significant results in several studies, side effects generally mild and transient, and moderate-to-high patient satisfaction — alongside substantial variation in injection areas and technique and limited consensus on optimal use^[7]. A parallel review of current practice reached a similar position, noting varying degrees of reported efficacy and the need for further research to establish optimal use^[8].

What is not established

Three things get quoted with more confidence than the sources support. There is no established universal session count or interval for either modality — the reviews describe heterogeneous schedules, not a consensus one. There is no established duration of benefit; the trials report outcomes at defined follow-up points, typically three to six months, and say nothing about what happens after. And there is no established comparative ranking between PRP, polynucleotides and the approved treatments for any given indication, because the head-to-head trials that would establish one have largely not been done.

Written by the Stem Cell Seoul editorial team and medically reviewed by a Korean Board-Certified Dermatologist (AAD International Fellow · ASLMS member). Last reviewed 2026-08-30.