Polynucleotides and PDRN: what the evidence actually shows

Polynucleotides are the fastest-growing search category in UK aesthetics, and the questions being asked — what they are, whether they work, how they differ from filler — suggest the marketing has run ahead of the explanation.

What they are

Polynucleotides (PN) and polydeoxyribonucleotides (PDRN) are fragments of DNA. Both are conventionally derived from the sperm cells of salmon or trout, purified to remove protein and leave the nucleotide chains themselves.

The two are related but not identical, and the distinction matters. PDRN denotes lower molecular weight fragments — the literature describes a range of roughly 50 to 1,500 kDa. PN denotes higher molecular weight material from the same source. The higher weight brings greater viscosity, and with it a longer-lasting physical presence in tissue.

Recent work has also described microbially derived PDRN as a sustainable alternative to the salmon-based product, which matters for anyone whose objection to the category is its origin.

The mechanism

This is where polynucleotides differ from everything else on an injectable trolley. They are not a filler and not a paralytic. They are proposed to work through a receptor.

The described pathway runs through the adenosine A2A receptor. Nucleotide fragments bind A2AR, which upregulates adenylate cyclase and raises cyclic AMP; raised cAMP activates protein kinase A, which increases CREB and dampens MAPK signalling. The downstream effect is anti-inflammatory, alongside stimulation of angiogenesis and fibroblast activity.

More recent experimental work extends the picture: in senescent macrophages, polynucleotides upregulated A2AR and PCK1, reduced oxidative stress and promoted M2 macrophage polarisation, with raised interleukin-10 and TGF-β.

Two things follow. The claimed effect is regenerative rather than volumetric — collagen synthesis, elasticity, texture — so nobody should expect projection. And the effect is biological, which means it takes time and varies between individuals in a way that a gel occupying space does not.

What the clinical evidence covers

Reported outcomes cluster around skin quality: pore size, texture, fine wrinkles, laxity. A prospective observational study looked specifically at periorbital rhytides, which is consistent with where the interest is — “polynucleotides for under eyes” is among the rising searches.

Where polynucleotides are combined with hyaluronic acid, the argument made is complementary rather than additive: HA addresses hydration and immediate elasticity while the nucleotides act on cellular repair over a longer horizon.

Where the evidence is thin

Honesty about this matters more than usual, because the category is being marketed hard.

• Much of the mechanistic work is in vitro or in animal models. The receptor pathway is well described; the leap from pathway to durable clinical benefit in a specific face is less well evidenced.
• Clinical studies are frequently small, observational and short. Prospective controlled trials with long follow-up are scarce.
• Product naming is chaotic. Brand names circulate as though they were categories, and practitioners comparing two products may be comparing different molecular weights, different concentrations and different course structures without realising it.

What this means for someone reading about them

Polynucleotides are a plausible and mechanistically coherent category with a real evidence base that is still early. They are not filler, they will not add volume, and any claim of an immediate visible result is describing swelling rather than regeneration.

The reasonable summary: promising, biologically interesting, and currently sold with more confidence than the published evidence supports.