If you have spent any time reading about aesthetics lately, you have probably seen polynucleotide injections described as the “breakout treatment” of recent years — sometimes under the eye-catching nickname “salmon DNA”. Search interest has climbed faster than almost any other injectable in the UK. But behind the buzz sits a genuinely interesting piece of regenerative science, and a treatment that does something quite different from the fillers most people picture when they think of injectables. Here is an honest, plain-English guide to what polynucleotides are, what they can realistically do, and how to choose a clinic well.
What are polynucleotide injections?
Polynucleotides — often abbreviated to PN, and closely related to the term PDRN (polydeoxyribonucleotide) — are purified fragments of DNA, most commonly derived from salmon or trout. That sounds surprising, but the material is heavily refined and purified, and DNA is a biologically universal building block, which is part of why it tends to be so well tolerated.
The key thing to understand is that polynucleotides are not a filler and not primarily a hydrator. Injected into the skin, they act as a regenerative signalling molecule — in effect, a message that prompts your skin to repair and renew itself. This puts them in the growing family of “skin quality” or “regenerative” injectables that aim to improve the health and resilience of the skin itself, rather than to plump a line or add contour.
How polynucleotides work beneath the skin
The mechanism is where polynucleotides get genuinely interesting. Once injected, they are thought to activate adenosine A2A receptors on fibroblasts — the cells responsible for producing collagen and maintaining the skin’s structural scaffold. That activation sets off a helpful cascade:
- Increased release of VEGF (vascular endothelial growth factor), which encourages the formation of tiny new blood vessels and improves the skin’s microcirculation.
- Stimulation of type I collagen synthesis, gradually improving firmness and structural quality in aged or damaged tissue.
- A measurable anti-inflammatory effect and general support for tissue repair.
Polynucleotides do not fill a line or inflate a hollow. They work more like a signal to the skin’s own repair crew — which is exactly why the results appear gradually rather than instantly.
That repair-focused action explains why polynucleotides are often chosen for thin, fragile or sun-damaged skin, and why some clinicians use them to help support recovery after laser resurfacing. It is a fundamentally different job from a hyaluronic acid filler, which works by holding water and adding volume.
Polynucleotides vs fillers vs Profhilo
Because these treatments are frequently confused, it helps to see them side by side. All three are injected, but they do very different things:
| Feature | Polynucleotides | Dermal filler | Profhilo |
|---|---|---|---|
| How it works | DNA fragments signal repair, stimulate collagen, improve microcirculation | Hyaluronic acid holds water to add volume | Hyaluronic acid bio-remodelling, boosts collagen and elastin |
| Adds volume? | No | Yes | No |
| Best for | Skin quality, texture, thin or damaged skin, under-eye repair | Structural volume loss, contouring, deep folds | Overall skin laxity, hydration and firmness |
| Typical longevity | 6–12 months | 6–24 months | 6–12 months |
The short version: if you want to rebuild the quality of tired, crepey or fragile skin, polynucleotides are in the frame. If you want to replace lost volume or reshape a feature, that is a filler’s job. Profhilo sits closer to polynucleotides in intent but works through hyaluronic acid rather than DNA fragments. Many people are candidates for more than one, and a good practitioner will explain where each fits. Our guides to Profhilo and to skin boosters more broadly go deeper on the alternatives.
Which areas can polynucleotides treat?
Polynucleotides are used across several areas where skin quality, rather than volume, is the concern:
- Under-eyes — one of the most popular uses. The thin, delicate skin here is notoriously hard to treat with volumising products, and the regenerative, reparative action of polynucleotides suits it well.
- Full face — for general improvements in texture, elasticity and radiance.
- Neck — a historically difficult area for skin quality that benefits from the collagen-stimulating effect.
- Hands — a commonly neglected, prematurely-ageing area where skin thickness and quality can be improved.
What does the evidence actually say?
This is where an honest guide has to be careful, because the marketing sometimes runs ahead of the data. There are two separate questions: is the underlying biology sound, and is there strong clinical proof for aesthetic results?
On the biology, the ground is fairly firm. The pharmacology of PDRN — the adenosine A2A receptor pathway and its downstream effects on collagen and healing — is reasonably well established in the scientific literature, including a 2017 systematic review. Polynucleotides have a history of use in wound healing and tissue repair that predates their cosmetic popularity.
On the aesthetic-specific evidence, the picture is more modest and worth being upfront about. Much of the published cosmetic research is small, often based on studies of fewer than 50 people, frequently split-face in design and typically open-label rather than blinded. In plain terms: the signals are encouraging and the mechanism is credible, but the volume of high-quality randomised controlled trial data specific to outcomes like under-eye rejuvenation and skin elasticity is still smaller than the deep evidence base behind Botox or hyaluronic acid fillers. That evidence is expected to grow as the treatment matures — but for now, realistic expectations and a practitioner who is honest about the limits both matter.
What to expect: sessions, longevity and cost
Polynucleotides are delivered as a series of small injections into the target area, often after a numbing cream is applied. Most clinics recommend a starting course of 2–3 sessions, usually spaced a few weeks apart, to build the regenerative effect. Because the treatment works with your skin’s own repair processes, results appear gradually — many people notice improved hydration and texture within a few weeks, with firmer, more resilient skin developing over the full course.
Results typically last 6–12 months, broadly comparable to Profhilo, after which many people opt for a maintenance session once or twice a year to preserve the effect.
On cost, UK pricing generally runs £250–£600 per session, with a full course of two to three sessions commonly totalling somewhere in the region of £400–£1,200. Prices vary by area, product and clinic. You may also come across a range of brand names — Plinest and Nucleofill are widely used in UK clinics, Plenhyage combines polynucleotides with hyaluronic acid, and Rejuran is a well-known salmon-derived brand referenced internationally. The specific brand matters less than the skill of the person injecting.
Is it right for you? Safety and who it is not for
Polynucleotides have a favourable safety profile, with minimal reported side effects. The most common are mild and short-lived — some swelling, small bumps, redness or bruising at the injection points, usually settling within a few days. No major safety signals appear in the current literature, though, as noted, the depth of that literature is still growing.
There are, however, sensible cautions. Because the product is derived from fish, anyone with a known fish or seafood allergy should always flag it before treatment. As with most injectables, treatment is typically avoided during pregnancy and breastfeeding, over active skin infections, cold sores or inflamed acne in the target area, and in anyone with certain autoimmune or clotting conditions — which is exactly what a thorough consultation and medical history are for. Polynucleotides also will not lift sagging tissue or replace lost volume, so if that is your main concern, they may be part of a plan rather than the whole answer.
Because these are injectable treatments that break the skin, who performs them is central to both your safety and your result. A properly trained medical professional working in a clean, regulated setting, using genuine products, is not a luxury — it is the baseline you should expect.
Making an informed choice
Polynucleotide injections are a genuinely interesting regenerative option for improving skin quality — particularly in tricky areas like the under-eyes — with a reassuring safety record and a credible scientific mechanism. The honest caveats are that they work gradually, do not add volume, need a course plus maintenance, and rest on an aesthetic evidence base that is still maturing. Go in with realistic expectations and they can be a rewarding addition to a skin-quality plan; if you are comparing regenerative options, our overviews of Profhilo, skin boosters and PRP therapy are a useful next read.
Above all, the clinic and the clinician matter more than the buzz around any single product. Use Clinic Finder to compare accredited clinics near you, check that your practitioner is a suitably qualified, properly insured medical professional, and ask directly about the product they use, their experience with your specific area, and how they manage the rare risks. A confident, honest answer to those questions tells you more than any marketing headline.
