Rejuran and polynucleotides: what the evidence actually shows

What Rejuran is

Rejuran is a Korean injectable whose active component is polynucleotides — long fragments of DNA, purified from salmon. It is injected into the skin in many small deposits across an area, rather than placed in one spot to build a contour.

The category it belongs to is skin quality: texture, elasticity, fine lines. It is not a filler, and it is not a lifting treatment. If the complaint is a hollow or descended tissue, this is the wrong tool regardless of how it is marketed.

Polynucleotides are one of the treatments South Korea is genuinely known for internationally, which is exactly why it is worth being careful about what is established and what is claimed.

What it is proposed to do

In laboratory and animal work, polynucleotides have been described as acting through adenosine receptor activation, promoting new blood vessel formation, stimulating fibroblasts, and remodelling the extracellular matrix.

That is a mechanism story, and mechanism stories are where aesthetic marketing does most of its work. A substance shown to stimulate fibroblasts in a dish has not thereby been shown to change how a person's face looks. The clinical question is separate, and it is the one below.

What the published evidence shows

A systematic review published in the Journal of Cosmetic Dermatology in December 2024 pooled the clinical literature on polynucleotides in aesthetic medicine. Its findings, stated as the reviewers state them:

• Nine studies, 219 patients in total.
• The studies were rated low to moderate quality, with none achieving full scores on the critical appraisal tools used.
• Six studies reported wrinkle improvement — half of those reached statistical significance.
• Improved skin texture and elasticity were reported, described as visible within about three months.
• Measures of haemoglobin and melanin gave mixed results.
• Side effects were mild and transient: localised pain, swelling, redness, itching, bruising. Two studies reported no side effects at all.
• Patient satisfaction was moderate to high.

The authors' conclusion, in full: "Polynucleotides offer promising potential in esthetic medicine; however, there is limited consensus regarding their optimal use. Rigorous, high-quality studies are essential to validate the effectiveness and safety of PN."

How to read that

Two readings are wrong, in opposite directions.

It does not mean the treatment does not work. Nine studies with consistent direction of effect, mild side effects, and satisfied patients is not nothing, and the reviewers describe the potential as promising.

It also does not support the confidence with which polynucleotides are sold. Two hundred and nineteen patients across nine low-to-moderate-quality studies, with half the wrinkle findings not reaching significance, is an early evidence base. Anyone quoting you a specific percentage improvement is quoting something other than this review.

The honest position is that this is a plausible, well-tolerated treatment whose effect size nobody can yet state precisely — and that it is being marketed as though somebody could.

What a course looks like

Rejuran is sold as a course rather than a single treatment, typically several sessions at intervals. Injections are numerous and shallow, so a topical anaesthetic is usual, and the characteristic short-term effect is small raised bumps at each injection point that settle over the following days, sometimes with bruising.

Because it is a course, the number that matters is the total: how many sessions are being proposed, at what interval, and what that comes to in full before you begin.

Questions to ask a Korean clinic

• Which product exactly, and what is its Korean name? Check which MFDS portal it is licensed on.
• How many sessions, at what interval, and what is the total for the course?
• What specifically are you expecting to change, and when should I judge it?
• Are you proposing this alongside anything else — and what is each one for?

The bottom line

Rejuran is a polynucleotide injectable aimed at skin quality rather than volume or lift. The pooled evidence as of the 2024 systematic review is nine studies of low to moderate quality covering 219 patients, reporting improvement in wrinkles, texture, and elasticity with mild and transient side effects — but with only half the wrinkle findings statistically significant and the reviewers calling for rigorous studies. Treat it as promising and early, and treat any precise promise about it as marketing.