Polynucleotides and Skin Boosters: What They Actually Do
"I'd like the salmon sperm one."
I have had this conversation more times than I expected this year, and I have some sympathy with it, because the internet has given polynucleotides a name that is memorable and an explanation that is largely absent.
So here is the explanation. What they are, what the evidence supports, what they will not do no matter how much you spend, and the group of people who should not have them at all.
What polynucleotides actually are
Polynucleotides are short, purified fragments of DNA. They are extracted from fish, usually salmon or trout, then purified and sterilised to a pharmaceutical standard so that no fish protein remains. What you are left with is the DNA structure itself, which is close enough to human DNA that the body recognises it and does not attack it.
They are injected into the dermis, the living layer of skin underneath the surface. In the UK they are regulated as medical devices rather than as medicines, which is a meaningful distinction and one I will come back to.
The name puts people off. The concept, once you strip away the marketing, is fairly ordinary: you are giving the skin a raw material and a reason to repair itself.
What they do to the skin, and what they do not
This is where most of the disappointment comes from, so I would rather set it out clearly before anyone books anything.
What the evidence supports. Polynucleotides improve skin hydration by holding water in the dermis. They support fibroblast activity, and fibroblasts are the cells that produce collagen and elastin, so over a course you tend to see better skin texture and a little more firmness. They have an antioxidant effect and they calm inflammation, which is why they are increasingly used for irritated, reactive, or post-procedure skin. Under-eye skin quality is where I see the most reliable change, because that skin is thin and responds visibly to better hydration.
What they will not do. They will not fill a line. They will not restore volume to a cheek or a temple. They will not lift anything. They will not replace sun protection, and they will not undo years of unprotected sun exposure in three sessions.
Be honest with yourself about which of those two lists describes what you actually want. If the answer is on the second list, a skin booster is not your treatment and no practitioner should sell you one.
On the evidence itself. I want to be straight about this, because it is the part that usually goes unmentioned. The research on polynucleotides is real but it is young. Most of it is small studies, a good proportion of it comes from Italy and South Korea where these products have been in use longest, and there are fewer large, well-controlled trials than there are for retinoids or for sunscreen. The direction of the evidence is genuinely encouraging. The volume of it does not yet match the confidence of the marketing.
Related reading: If you want the treatment with the deepest evidence base in all of skincare, it is not an injectable and it costs a fraction as much: The Retinoid Evidence Base: A Pharmacist's Review.
A skin booster is not a filler
This confusion causes more unhappy patients than anything else in aesthetics, so I would rather pin it down.
A dermal filler is a gel, usually hyaluronic acid, placed to occupy space. Its job is structural. It restores volume where volume has gone, or it supports a feature. You can see the result the day it is done, because the substance itself is doing the work.
A skin booster is placed to improve the quality of the skin rather than its shape. It does not occupy space in the same way. Some skin boosters are hyaluronic acid based, some are polynucleotide based, but the intention is the same: better hydration, better texture, better resilience. The result appears gradually, over weeks, because your own cells are producing it.
One changes the architecture. The other changes the fabric. A woman who wants her skin to look less tired and more even is asking for the second, and is frequently sold the first.
What supports this work at home:
Skin boosters & polynucleotides
from £120
PRIORI DNA fx221 Recovery Serum
£99
Zooki Marine Collagen 5,000mg
from £2.50
Who they suit, and who should not have them
They tend to suit skin that looks tired rather than lined. Thin, crepey under-eye skin. Dull texture that no amount of good skincare has improved. Skin that reacts to everything and needs calming rather than resurfacing. Skin recovering from a course of stronger treatments. Women in their late thirties through fifties who are noticing quality changing rather than volume disappearing.
Do not have them if you are pregnant or breastfeeding, if there is any active infection or active acne at the injection site, or if you have an autoimmune condition without discussing it properly with your practitioner first.
And this one matters most. Polynucleotides are derived from fish. If you have a fish or seafood allergy, you must say so before anything is booked, not on the day. The purification process removes the protein that causes allergic reactions, and reactions are rare, but "rare" is not the same as "no". Any practitioner who does not ask you about this before injecting is not doing the consultation properly.
If you take anticoagulants, or you bruise very easily, say so too. It does not necessarily rule the treatment out, but it changes how it should be done and what to expect afterwards.
What a course actually involves
Not one appointment. This is the second most common misunderstanding.
A typical course is two to three sessions spaced two to four weeks apart, then maintenance somewhere between six and twelve months later depending on the area and how your skin responds. Anyone quoting you a single session and a dramatic result is selling something other than polynucleotides.
Afterwards, expect small raised bumps at each injection point for around 24 to 48 hours. That is normal and it settles. Bruising is possible, particularly under the eyes, so do not book this the week of a wedding. Results build across four to eight weeks rather than appearing immediately, which is disorienting if you are used to treatments that show up the next morning.
Everyone's skin responds differently, and I would not promise you a specific outcome before I had looked at your skin.
How to decide
Ask yourself one question: do you want your skin to look different in shape, or different in quality?
If the honest answer is quality, a skin booster is a reasonable option and polynucleotides are a reasonable version of it, with the caveat that the evidence is younger than the enthusiasm. If the honest answer is shape, this is not your treatment and a good practitioner will tell you so before taking your money.
And if you are not sure, that is exactly what a consultation is for. At Debora Tentis Clinic that means looking at your skin properly, going through your medical history, asking about allergies before anything else, and telling you honestly if the answer is that you would get more from £120 of sunscreen and a retinoid than from an injectable. Sometimes it is.
Shop
Skin boosters & polynucleotides
from £120
PRIORI DNA fx221 Recovery Serum
£99
PRIORI LCA fx121 Skin Renewal Cream
£65
Heliocare 360° Mineral Tolerance Fluid SPF 50
£23.50
Zooki Marine Collagen 5,000mg
from £2.50
NEOSTRATA Restore Bionic Face Serum
£55.50
Keep reading: What should actually change in a skincare routine between your twenties and now, and what is fine to leave alone: Your Skincare Routine at 25 vs Now.
Debora Tentis is a Women's Health Pharmacist, Independent Prescriber Trainee and aesthetics practitioner at Debora Tentis Clinic, Milton Keynes. This post is for educational purposes only and does not constitute medical advice. No treatment outcome is guaranteed.
