You slept a full night, and the mirror still disagrees. The shadow under your eyes did not get the message, concealer only half hides it, and by now you have probably seen polynucleotides described as regeneration in a syringe, or sold under the name salmon DNA. The interest is fair. The description is not, and the under-eye is the area where treating the wrong thing shows the most.
Do polynucleotides under eyes actually work? For the quality of the skin itself, its thickness, texture and hydration, yes. In the one proper head-to-head trial under the eye they matched a plain hyaluronic acid and edged it on the measures that decide a tired under-eye: surface texture, pore refinement and elasticity. What they are not is a filler, so they will not raise a hollow or lighten a pigment. The question that actually matters, then, is not whether they work, but which of the three things an under-eye can be is the one troubling yours, because that is what decides whether they are the right tool for your face.
| Under-eye polynucleotides | At a glance |
|---|---|
| What they are | Purified DNA fragments, usually from salmon or trout, that signal the skin’s own fibroblasts, not a DNA-repair treatment |
| What they do | Improve the quality of the skin: its thickness, texture and hydration |
| What they don’t do | Fill a hollow or lighten a pigment: neither, at any dose |
| Best for | Thin, crepey, poor-quality under-eye skin (the bluish tint of thin skin) |
| Course & upkeep | Three sessions, two to three weeks apart, then maintenance around six months |
| Evidence | Ahead of a plain hyaluronic acid on texture, pore refinement and elasticity; level overall (split-face RCT, PMID 32248707) |
| Cost at Baudelaire | £325 a single session, £875 the course of three |
Start with the name, because it misleads. Polynucleotides are fragments of DNA, and calling an injection by that name makes people assume it repairs the DNA in their skin. It does not. What it actually does is more precise, and more useful, and worth understanding before you spend a few hundred pounds on it.
What polynucleotides are
They are long chains of purified DNA, usually taken from salmon or trout, cleaned of the proteins that would cause a reaction and cut to a set range of lengths. Injected into the skin, they are not read as genetic instructions. They work as a signal: they hold water in the tissue, mop up free radicals, and prompt fibroblasts, the cells that build and maintain the skin’s support structure, to work harder (systematic review, PMID 39645667). That mechanism comes from laboratory and animal studies; the human trials measure the result, not the pathway, so I keep it at that level.
In short: they signal the skin’s own cells and improve the tissue around them. They do not repair your DNA. The honest mechanism is the more interesting one anyway.
What that does to the skin
A fibroblast prompted this way behaves, for a while, like a younger and busier one: making more of the proteins that give skin its structure, and holding more water. On skin that suits it, that shows as an under-eye a little thicker, less crepey and better hydrated, so the tired, bluish look that comes from thin skin eases. It works on the quality of the skin itself, and for thin under-eye skin, that is precisely the thing worth improving.
Polynucleotides change the quality of the skin, not its shape, and thin, tired under-eye skin is exactly the quality they answer to. The skill is knowing when that is what you are looking at.
The point that decides itWhat the under-eye evidence shows
What the best study actually found. The most relevant evidence is a 2022 randomised, double-blind, split-face trial: 27 people, three injections two weeks apart, polynucleotide on one side of the eye area and a plain (non-crosslinked) hyaluronic acid on the other (split-face RCT, PMID 32248707).
- Polynucleotide came out ahead on the skin-quality measures that matter for an under-eye, surface roughness and pore size, and held its improvement in elasticity and hydration longer than the hyaluronic acid.
- On the overall aesthetic score the two were level, and matching an active comparator that was itself working is a genuine result, not a null one.
- There were no serious side effects on either side.
Read it plainly: against a treatment that was already doing something, polynucleotides did more on exactly the measures that read as tired under-eye skin. A 2025 systematic review of the wider evidence lands in the same place, consistent, well tolerated, and honest that larger trials will sharpen the picture further (PMID 39645667). That is a treatment worth reaching for on the right skin, described exactly as it is.
Why an under-eye looks tired, and which part this treats
Before treating anything, this is the assessment that matters. “Dark circles” is not one thing. It is usually four, mixed in different amounts:
- A hollow or shadow, where the dip from lower lid to cheek has deepened and casts a shade. That is about structure and light, and it is treated, when it should be, with carefully placed filler, not by improving the skin.
- Pigment, real brown colouring in the skin, often inherited or from the sun. That needs a pigment treatment; polynucleotides do not lighten it.
- Vascular, the blue and violet of the vessels themselves reading through the lower lid. That is treated at the vessel, with laser, rather than by thickening the skin over it.
- Thin, poor-quality skin, through which whatever sits beneath shows through, and which looks crepey on its own. This is the part polynucleotides genuinely help.
They treat the fourth, and treat it well. Aim them at a shadow, a pigment or a vessel and they cannot win, which is how a good treatment earns a bad name it does not deserve. The entire skill is the reading: naming which of the four is driving your under-eye, then reaching for the tool that matches it. I set out the kinds of dark circle and how each is treated in a separate guide.
How long they last, and how many sessions
The effect builds over a short course rather than arriving in one visit, and it fades the same way. In the trial it was three sessions two weeks apart (PMID 32248707), which is close to how I do it: a course of three, two to three weeks apart, then a review, with a maintenance session after around six months. One session is a start, not the treatment. Any exact figure you are given for a single session is a guess. At Baudelaire, polynucleotides for the under-eye are £325 for a single session, or £875 for the course.
Polynucleotides are a precise, well-evidenced way to rebuild the quality of thin under-eye skin, sold, too often, under a name and a story that promise something else entirely. Named correctly and aimed correctly, they are one of the better tools we have for that skin.
Read the under-eye right, reach for the tool that matches it, and the result follows. That reading is where I would start, and it is what a consultation is for.
