Treatment & Procedure
Polynucleotides / PDRN (“salmon DNA”, skin booster)
Biohacking
“Salmon DNA” sounds like marketing, but describes fairly precisely what is injected: purified DNA fragments from the germ cells of salmon or trout. As skin boosters, they are supposed to build up the skin from within and make it smoother, plumper and more resilient. For wounds and scars there are first randomized data on this, for rejuvenation so far only small studies.
In short
Polynucleotides (PN) are longer, PDRN (polydeoxyribonucleotide) shorter DNA chains from fish. In cell and animal experiments, PDRN activates the adenosine A2A receptor, which dampens inflammation and promotes the formation of new blood vessels; for the longer polynucleotides, a water-binding scaffold in the skin is assumed. In 2026, a systematic review found seven randomized trials with a total of 183 participants on skin rejuvenation, scars and wound healing, all with improvements and without serious side effects, most clearly for wound healing. The catch: the trials are small and short, only a single one compared double-blind against saline, and against hyaluronic acid there was no difference in the overall assessment.
What polynucleotides and PDRN are and how they work
Both substances are obtained from fish: polynucleotides from the testes of fish such as salmon or trout, PDRN mainly from the sperm of rainbow trout and chum salmon. The difference lies in the chain length. The terms are not used consistently in studies and advertising, which makes comparison difficult.
For PDRN, two pathways of action have been described. It binds to the adenosine A2A receptor, which dampens inflammation, dilates vessels and stimulates the formation of new blood vessels. And via the so-called salvage pathway it supplies building blocks from which cells build new DNA. For the longer polynucleotides, a water-binding scaffold is assumed that is supposed to support the remodelling of connective tissue; a review from 2024 notes that the mechanism of polynucleotides has not yet been researched. They are injected into the skin, in the studies usually in several sessions, for example three times two weeks apart. Related approaches that also aim at skin regeneration are exosomes, PRP and GHK-Cu.
What is well supported
Wound healing is furthest along: in the randomized trials, pressure ulcers and skin graft donor sites healed faster under PDRN, and the epidermis closed earlier. For scars there are two interesting studies: after thyroid surgery, redness, discomfort and scar height were lower with PDRN injections, and in acne scars the scars improved in a small double-blind study only under polynucleotides, not under saline.
For skin quality, split-face studies show improvements in elasticity, moisture, roughness and pores. Serious side effects did not occur in any of the randomized trials.
What the studies show
Alhussain 2026 — systematic review
Seven randomized trials from 2004 to 2025 with a total of 183 participants, 10 to 42 per trial, follow-up two weeks to six months. Four concerned skin rejuvenation, three of them in a split-face comparison, one scar prevention after thyroid surgery, two wound healing in pressure ulcers and skin graft donor sites. All reported improvements, most consistently for wound healing. The authors consider the evidence limited by small sample sizes and inconsistent protocols.
Araco 2021 — acne scars against placebo
20 women between 30 and 50 years of age with moderate to severe acne scars; 10 each received polynucleotides or saline, and neither doctor nor patient knew what was injected. Only in the polynucleotide group did the scars improve significantly compared with baseline after one and three months, measured with 3D imaging.
Kim 2023 — scars after thyroid surgery
44 patients after open thyroid surgery, randomly assigned to two PDRN injections on the first and second day after surgery or no treatment. After three months, the scar score was 1.62 versus 2.50 points, narrowly not significant (p = 0.059); vascularity, discomfort, redness and scar height were significantly lower. There was no sham injection.
Lee 2022 — eye area compared with hyaluronic acid
27 people, one half of the face with a polynucleotide filler, the other with a non-crosslinked hyaluronic acid filler, three sessions each two weeks apart, double-blind. In the overall assessment and on the satisfaction scale, the sides did not differ. Elasticity, moisture, roughness and pore volume improved more on the polynucleotide side. No serious side effects.
What users report
An observational study collected 106 questionnaires from 66 patients after three sessions on the face, neck or décolleté. The practitioners saw an improvement on the face in all cases, a clear or excellent one in 53.5 percent; satisfaction among those treated was between 97 and 100 percent, and there were no serious side effects. The evaluation had no control group and is based on spontaneously reported side effects.
Where the data stop
The studies are small, short and hardly comparable: different products, chain lengths and protocols, often combined with laser or microneedling and mostly against another treatment or none at all instead of against a sham injection. A randomized trial on crow’s feet was retracted in 2026 because the comparator product was mislabelled. Whether polynucleotides slow skin ageing or change anything beyond a few months has not been studied by anyone.
This applies even more to serums and creams with “salmon DNA”: the studies concern injections and applications on freshly lasered or needled skin. Whether a serum works similarly on intact skin is not shown by them.
Status, approval and legal
Injectable polynucleotides are marketed in the EU as class III medical devices with CE marking, not as medicines. In South Korea, PDRN is approved as a medicine for wound healing and tissue regeneration, and polynucleotides are medical devices there. In cosmetics, PDRN appears in the list of ingredients as “Sodium DNA” or “Hydrolyzed DNA”.
An injection into the skin belongs in medical hands, with proper hygiene and a product of traceable origin. Aesthetic treatments are paid for out of pocket.
Safety
No serious side effects occurred in the randomized trials; typical are temporary swelling, redness and pain at the injection site. Systematic long-term data and a registry do not exist.
As with any injection, infections can occur. A London case report from 2026 describes a healthy 57-year-old woman who, after polynucleotide injections, developed abscesses on both cheeks with the gram-negative bacteria Enterobacter cloacae and Klebsiella variicola; they had to be opened, and sunken scars remained after six months. It was the first culture-confirmed case of this kind in the literature. The material comes from fish; anyone who is allergic to fish should clarify this with a doctor beforehand.
BK-Score Thin human evidence
| Human evidence | 4 | |
|---|---|---|
| Mechanism | 4 | |
| Safety data | 4 | |
| Hype gap | 3 | |
| Track record of use | 5 |
Evidence 4, because there are several small randomized trials – a systematic review found 7 with a total of 183 participants (Alhussain 2026), and only one acne scar study with 20 women compared double-blind against saline (Araco 2021) –, but most compare against other treatments or untreated controls, and in the comparison with hyaluronic acid in the eye area the overall assessment did not differ (Lee 2022). Mechanism 4, because for the shorter PDRN an effect via the adenosine A2A receptor has been shown mainly in cell and animal experiments, while for the longer polynucleotides only a water-binding scaffold is assumed; a review notes that the mechanism has not yet been clarified (Lee 2024). Safety 4, because the small trials report no serious side effects, but registries and long-term data are lacking, and individual cases such as abscesses on both sides with permanent scars have been described (Shanshal 2026). Hype 3, because “salmon DNA” is marketed as regeneration at the cellular level and as a skin booster trend, but the evidence comes from a few small studies with short follow-up, one of which was retracted in 2026 because of a mislabelled comparator product. Use 5, because PDRN has been used in studies on wound healing since at least 2004 and is approved as a medicine in South Korea, and polynucleotides are injected as medical devices in the EU and Asia, but systematic recording of the uses is lacking (Kim 2025). Direction mixed. For comparison: Argireline (4/4/6/3/8) and GHK-Cu (4/7/6/4/5) as similarly thinly supported skin agents, exosomes (2/3/1/1/3) as an even less studied injection trend.
The score rates the state of knowledge, not the substance. “Safety data 9” means well studied – not harmless.
Subjective assessment by Biohacking Kompakt based on published scoring rules – not a scientific rating and not a medical recommendation. Rules and all ratings (German)
Frequently asked questions about polynucleotides and PDRN
What are polynucleotides?
Purified DNA fragments from the germ cells of salmon or trout. Polynucleotides are the longer chains, PDRN the shorter ones. They are injected into the skin as skin boosters and are supposed to improve skin quality, scars and wound healing.
Is it really salmon DNA?
Largely yes. Polynucleotides are obtained from the testes of fish such as salmon or trout, PDRN mainly from the sperm of rainbow trout and chum salmon. They do not act as genes; the pathways described are a signal at the adenosine receptor and a supply of DNA building blocks.
Does a serum with salmon DNA work the same way?
That has not been shown. The studies concern injections or application on freshly lasered or needled skin. In cosmetics, PDRN usually appears on the pack as “Sodium DNA” or “Hydrolyzed DNA”.
Are polynucleotides better than hyaluronic acid?
In a split-face study with 27 people in the eye area, the overall assessment did not differ. Elasticity, moisture, roughness and pores improved somewhat more on the polynucleotide side.
How safe are polynucleotide injections?
In the small randomized trials there were no serious side effects, mostly only swelling and redness. Long-term data are lacking, and abscesses on both sides with permanent scars have been described as an individual case. The injection belongs in medical hands.
Related
- Related topicSkin rejuvenation (laser, microneedling, radiofrequency)
- Related topicExosome therapy
- Related topicBotulinum toxin (“Botox”) for expression lines
- Same sectionPRP (Platelet-Rich Plasma)
- Same sectionUV and Laser Blood Irradiation (UVBI, ILIB)
- Same sectionOzone therapy
Sources
- Alhussain et al., Cureus 2026 (systematic review, 7 randomized trials)
- Araco & Araco, Aesthet Surg J 2021 (acne scars against placebo)
- Kim et al., Adv Wound Care 2023 (PDRN after thyroid surgery, randomized)
- Lee et al., J Dermatolog Treat 2022 (polynucleotide versus hyaluronic acid, split-face)
- Kim, Pharmaceutics 2025 (PN and PDRN: origin, mechanisms, approval)
- Lee et al., Int J Mol Sci 2024 (review of aesthetic use)
- Eliana et al., J Cosmet Dermatol 2026 (observational study, 66 patients)
- Shanshal et al., J Cosmet Dermatol 2026 (case report: abscesses after injection)
- J Cosmet Dermatol 2026, retraction of a randomized trial on crow’s feet
Open in the database – with search, filters and comparison (German app)
Information only, not medical advice and not a usage or dosage recommendation. Prescription-only and unapproved substances belong in the hands of a physician. Last updated: 2026-11-07.