Dr. Ayşegül Girgin · Aesthetic Medicine · Reading time ~12 minutes · Last updated: 30 October 2026
Short answer
Polynucleotides are purified fragments of DNA, usually taken from salmon or trout, that are injected into the skin with the aim of improving skin quality. The clinical data are limited: studies are small, follow-up is short and few trials are controlled. They are not a filler, and whether they suit you can only be decided after an in-person assessment.
Polynucleotide injections are now widely discussed in the UK, often with more certainty than the research supports. This article explains what polynucleotides are, how they differ from PDRN and from dermal fillers, what the published studies do and do not show, and which questions to ask before considering treatment, in the UK or in Istanbul.
What Are Polynucleotides?
Polynucleotides are long chains of nucleotides, the building blocks of DNA, extracted and purified for medical use. The products used in aesthetic medicine are generally made from the reproductive cells of fish such as salmon and trout, which are processed so that the DNA fragments remain and other material is removed.
They are injected into or just beneath the skin in many small amounts, most often under the eyes, across the face, on the neck or on the chest. The stated aim is a gradual change in skin quality, such as hydration, elasticity and fine lines, rather than adding volume.
Polynucleotide injections are offered only to adults aged 18 and over. No product is named here, because the evidence differs from one formulation to another.
Polynucleotides and PDRN: Are They the Same Thing?
Not quite, although the names are often used as if they were. PN (polynucleotides) and PDRN (polydeoxyribonucleotide) are both DNA-derived polymers from fish, and a 2025 review in Biomolecules noted that papers have used the terms interchangeably, causing considerable confusion.
The main difference is chain length: PDRN is made of shorter fragments and PN of longer chains. The 2025 review proposed a molecular-weight cut-off of 1,500 kDa to separate the two names; this is a proposal, not an agreed standard.
| Feature | Polynucleotides (PN) | PDRN |
|---|---|---|
| Chain length | Longer chains, higher molecular weight | Shorter fragments, lower molecular weight |
| Proposed action | Structural and hydrating support; forms a water-holding gel | Acts on adenosine A2A receptors; linked to repair and new blood vessels |
| Main areas of research | Skin quality and ageing, mostly in small studies | Wound healing and tissue repair, as well as skin |
| Regulatory example | Classed as a medical device in South Korea | Approved as a medicine for graft-related wounds in South Korea |
Classification differs between countries, so the last row is an example rather than a rule. Research on one formulation or use cannot simply be transferred to another, which is worth remembering when a clinic quotes a study.
How Are Polynucleotides Thought to Work?
The mechanism is proposed rather than proven in people. Much of it comes from laboratory work, and reviews use cautious language such as “may” when describing effects in skin.
- Hydration and support: longer PN chains bind water and form a gel-like structure in the skin.
- Cell signalling: PDRN fragments act on adenosine A2A receptors, which are involved in inflammation, blood vessel formation and repair.
- Recycling: fragments are broken down into building blocks that cells can reuse (the salvage pathway).
- Fibroblast activity: reviews suggest polynucleotides may support fibroblasts, the cells that make collagen and elastin.
A mechanism shown in a laboratory does not guarantee a visible change in your skin, which is why the clinical studies matter more.
What Does the Clinical Evidence Show So Far?
The clinical evidence is limited: there are small studies with encouraging findings, but not yet the large, independent, controlled trials with long follow-up needed for firm conclusions.
- A systematic review in the Journal of Cosmetic Dermatology found nine studies with 219 patients in total, ranging from 5 to 72 people each. Quality was rated low to moderate, methods were too varied to combine the results, and two of the review’s authors declared links with companies that make or distribute polynucleotide products.
- A 2026 systematic review of randomised trials in Cureus found seven trials with 183 participants, only four of them on skin rejuvenation. Most analysed fewer than 30 people, and the authors called for larger trials with standardised products and longer follow-up.
- A 2026 study of treatment around the eyes followed 42 adults, but had no control group or blinding and relied mainly on patients’ own ratings. Its authors described the findings as hypothesis-generating.
| Question | What the studies report | Strength of evidence |
|---|---|---|
| Does skin quality change? | Small studies report improvements in fine lines, texture and elasticity | Low to moderate: small, varied studies, some industry involvement |
| How long do effects last? | Most studies followed people for about 12 to 28 weeks | Very limited: longer-term durability is largely unstudied |
| What side effects occur? | Mostly mild, short-lived reactions; no serious events reported in the reviewed studies | Limited: studies this small cannot detect rare events |
| Do they outperform other treatments? | Very few direct comparisons | Insufficient to say |
Claims that results last six to nine months are common online, but most studies stopped following patients before that point, so such figures are not well supported and no result can be promised.
If you would rather wait for stronger evidence
That is a reasonable position. Larger independent trials may clarify who, if anyone, benefits. There is no medical need to have this treatment, and options with a longer research history can be discussed in the meantime.
How Are Polynucleotides Different From Dermal Fillers?
Dermal fillers add volume and shape, whereas polynucleotides aim to change skin quality and do not fill hollows or lines.
| Feature | Polynucleotides | Hyaluronic acid filler |
|---|---|---|
| Substance | Purified fish-derived DNA fragments | A gel made from hyaluronic acid |
| Aim | Skin quality: hydration, texture, fine lines | Volume and contour |
| When change is seen | Gradually, over weeks, if at all | Mostly at the time of treatment |
| Can it be dissolved? | No specific dissolving agent | Can be broken down with hyaluronidase |
| Evidence base | Limited clinical data, small studies | Longer history of use and a larger body of research |
Hyaluronidase is prescription-only, used after an in-person medical assessment. Some polynucleotide products also contain hyaluronic acid, so it is worth asking exactly what is in the syringe.
The term skin booster is used loosely for several injectable skin-quality treatments, and our page on the youth vaccine skin treatment describes one of them. Polynucleotides are also sometimes grouped with collagen stimulation treatments, although the substances and evidence differ.
Who May Not Be Suitable for Polynucleotide Injections?
Polynucleotide injections may not be suitable if any of the points below apply. The list is not complete; suitability is decided only after an in-person assessment of your medical history, medicines and allergies.
- You are under 18.
- You are pregnant or breastfeeding, as these groups have not been studied.
- You have a known allergy to fish or seafood, or have reacted to a fish-derived product before.
- You have an active infection, cold sore or inflamed skin in the area to be treated.
- You have an autoimmune condition, a bleeding disorder or take medicines that affect clotting or immunity, unless this has been discussed with your own doctor first.
- Your main concern is volume loss, deep folds or loose skin, which polynucleotides are not designed to address.
- You are looking for a specific or predictable result, which the current evidence cannot support.
Fish allergy deserves a clear answer, because advice online is inconsistent. People with fish allergy have been excluded from at least some clinical studies, so there are no reliable data on how they respond. As the products are fish-derived, a cautious and consistent approach is to treat a fish allergy, or a past reaction to a fish-derived product, as a reason not to proceed.
What Side Effects and Unknowns Should You Weigh Up?
The side effects reported in studies are mostly local and short-lived: swelling, redness, itching, bruising and small raised bumps where the needle went in. In the reviewed studies these were described as mild, and no serious adverse events were reported.
The unknowns matter as much. Studies of a few dozen people cannot show how often rare reactions such as allergy, infection or persistent lumps occur, and there is little information on repeated courses over several years.
Polynucleotides aftercare
Aftercare is usually simple: keep the area clean, avoid rubbing it, and follow your clinic’s written instructions on make-up, exercise and heat for the first day or so. If bumps at the injection points do not settle, contact the clinic.
Warning signs that need urgent attention:
- Swelling of the lips, tongue or throat, wheezing or difficulty breathing: call 999 in the UK, or the local emergency number.
- Any change in vision after injections near the eyes: seek emergency care.
- Pain, redness or heat that gets worse rather than better, pus or a fever.
- Lumps or swelling that persist or appear days to weeks after treatment.
In the UK, suspected problems with medicines and medical devices can be reported to the MHRA through the Yellow Card scheme.
What Questions Should You Ask Before Considering Treatment?
The most useful questions test the product, the evidence and the plan, not just the procedure itself.
- Product: which product will be used, who makes it, and is it PN, PDRN or combined with hyaluronic acid?
- Regulatory status: what conformity marking does it carry, and can you see the batch number afterwards?
- Evidence: what published studies exist for this product in the area you want treated?
- Who treats you: who assesses and injects you, and what are their medical qualifications?
- The plan: how many sessions, at what intervals, and at what point would you stop if nothing changes?
- Problems: what are the warning signs, and whom do you contact if something goes wrong?
To see how the clinic in Istanbul approaches this treatment, read the page on polynucleotide injections at the clinic.
If you are considering treatment in Istanbul
- An in-person consultation takes place before any treatment, and you can decide not to go ahead.
- You receive a written treatment plan and, afterwards, an English-language medical report listing the product, batch number, areas treated and dates.
- A course usually involves several sessions weeks apart, which is hard to fit into a single visit; consider whether treatment closer to home suits you better.
- Follow-up after you return is remote. There is no UK clinic or UK aftercare partner; if a problem arises in the UK you would see your GP, call NHS 111 or attend A&E, taking your medical report with you.
- Speak to your GP before travelling, and read the health section of the UK government’s foreign travel advice for Türkiye, which includes information on medical treatment abroad.
Questions about polynucleotides?
Whether any treatment is suitable for you can only be decided after an in-person assessment. If you would like to discuss the evidence, your medical history or your allergies, you can contact the clinic.
Related pages:
Polynucleotide injections ·
Youth vaccine ·
Collagen stimulation treatment
Frequently asked questions
Are polynucleotides made from salmon DNA?
Most injectable products are made from DNA taken from the reproductive cells of salmon or trout, which is then purified. This fish origin is the reason allergy questions are part of every consultation, and why you should mention any past reaction to fish, seafood or fish-derived products.
Can I have polynucleotides if I have a fish allergy?
A cautious answer is no. Because people with fish allergy have been left out of at least some studies, nobody can say how they would respond, and there is no reliable evidence to reassure them. Mention any allergy, however mild, and any reaction to previous injections, so that it can be assessed properly.
How many sessions are usually recommended?
In the studies included in one systematic review, people typically had three or four sessions, most often two to four weeks apart. There is no agreed standard protocol, and doses and techniques varied between studies. Any plan should be set after an in-person assessment and include a clear point at which to stop if nothing is changing.
Do polynucleotide injections hurt?
Most people feel a sharp scratch or sting with each small injection, and a numbing cream may be applied beforehand. In one study of treatment around the eyes, participants reported mild swelling and discomfort lasting around two days. How much it is felt varies from person to person.
Can polynucleotides be dissolved like hyaluronic acid filler?
No. Hyaluronidase breaks down hyaluronic acid and is not a dissolving agent for polynucleotides, which the body is expected to break down over time. Hyaluronidase is prescription-only, used after an in-person medical assessment. If a product combines polynucleotides with hyaluronic acid, only the hyaluronic acid part would be affected.
How are polynucleotides regulated in the UK?
Polynucleotide injectables are generally classified as medical devices rather than medicines. In the UK the MHRA regulates medical devices; devices placed on the market in Great Britain must be registered with it and carry a UKCA mark or, under transitional arrangements, a CE mark. This article cannot confirm the status of any individual product, so ask the clinic.
About the author
Dr Ayşegül Girgin is a medical doctor practising in Istanbul, Türkiye (registered in Türkiye). She graduated from Ege University Faculty of Medicine in 1992 and has worked in aesthetic medicine since 1997. She carries out academic work on facial anatomy at the Department of Anatomy, Trakya University Institute of Health Sciences; her cadaver study of the periorbital retaining ligaments was published in the journal Anatomy (2025). She is a co-author of a Turkish handbook on aesthetic botulinum toxin use and a co-translator of Turkish editions of textbooks on dermal fillers and mesotherapy. She sees patients at Smileest Clinic in Nişantaşı and Koşuyolu, Istanbul.
Medical sources
- Lampridou S et al. Journal of Cosmetic Dermatology — The Effectiveness of Polynucleotides in Esthetic Medicine: A Systematic Review
- Alhussain et al. Cureus, 2026 — Polynucleotides and Polydeoxyribonucleotides for Skin Rejuvenation, Postoperative Scar Prevention, and Wound Healing: A Systematic Review of Randomized Clinical Trials
- Marques C et al. Biomolecules, 2025 — From Polydeoxyribonucleotides (PDRNs) to Polynucleotides (PNs): Bridging the Gap Between Scientific Definitions, Molecular Insights, and Clinical Applications of Multifunctional Biomolecules
- Kim ST. Pharmaceutics, 2025 — Comparison of Polynucleotide and Polydeoxyribonucleotide in Dermatology: Molecular Mechanisms and Clinical Perspectives
- Ziade G et al. Journal of Cosmetic Dermatology, 2026 — Prospective Observational Study of Polynucleotide Injections for Periorbital Rhytides
- GOV.UK / MHRA — Regulating medical devices in the UK