PN Is Not PDRN

PN and PDRN are often used interchangeably in marketing copy. They shouldn't be. Both are polynucleotides typically derived from salmon DNA, but they are different materials with different molecular profiles, and the distinction matters when you are choosing products or explaining a treatment to a client.

In our training rooms the question comes up most weeks. A clinic has a PDRN booster on the shelf, a rep has just described a PN injectable, and the two words have been used as if they were one. They are related. They are not the same, and a practitioner who can explain the difference in two sentences is in a stronger position with clients and with suppliers alike.

Where both materials come from

Both PN and PDRN are fragments of DNA purified from salmon sperm. A 2017 review in Frontiers in Pharmacology describes the raw material for PDRN as DNA from salmon trout (Oncorhynchus mykiss) or chum salmon (Oncorhynchus keta), purified at high temperature so that proteins and peptides are inactivated and the finished substance is more than 95 per cent DNA fragments.

What differs is what happens after purification. The DNA is broken into pieces, and the length of those pieces decides whether the material is described as PDRN or PN. Same fish, same molecule, different chain length.

PDRN: the shorter fraction

PDRN (polydeoxyribonucleotide) refers to shorter DNA fragments, generally in a lower molecular-weight range. The Frontiers review gives that range as roughly 50 to 1,500 kDa, with most of the fragments sitting between 80 and 200 kDa. Research interest in PDRN has centred on its interaction with adenosine A2A receptors and its role in supporting tissue-repair processes, which is why it appears so often in post-procedure and regeneration-focused products.

Two mechanisms are described in the literature. The first is receptor signalling. PDRN acts as an agonist at the adenosine A2A receptor, and in experimental models blocking that receptor removes the effect, which is reasonable evidence that the receptor is doing the work. A narrative review in the Journal of Cutaneous and Aesthetic Surgery treats this as the principal mechanism. The second, described in the Frontiers review, is the salvage pathway: cells take up the nucleosides and nucleotides released from PDRN and reuse them to build new DNA at times when demand is high and normal synthesis is under strain.

The strongest clinical data for PDRN is not in aesthetics. The same review reports a randomised trial in diabetic foot ulcers in which complete healing within eight weeks was recorded in 37.3 per cent of patients treated with injected PDRN against 18.9 per cent on placebo. That is a wound-healing result, in a licensed medicine, in a population very different from an aesthetic clinic. It explains why the material is taken seriously. It does not transfer directly to a serum.

PN: the longer chains

PN (polynucleotide) describes longer, higher molecular-weight chains. In injectable aesthetics, PN-based products are typically discussed in terms of their physical scaffolding behaviour and hydration capacity as much as their biological signalling. The commonly cited dividing line is around 1,500 kDa. Below it the material is generally described as PDRN; above it, as PN.

Longer chains are usually described as more viscous, better at holding water, and able to form a loose three-dimensional mesh that is talked about as a scaffold for fibroblasts. That physical behaviour is the reason PN injectables are positioned for skin quality. It is also the reason their evidence base, mechanism and regulatory classification should be assessed on their own terms rather than borrowed from PDRN.

Topical products are a different conversation again

In topical and cosmetic contexts the regulatory and evidence pictures are different again: concentration, fragment size and formulation all vary widely between products, and findings from injectable studies do not automatically transfer to topical use. A cosmetic serum containing salmon DNA is not the same proposition as an injected medicine. The honest way to describe it is as a hydrating, skin-conditioning ingredient with a regenerative rationale, used to support the skin before and after procedures.

The questions to ask

The professional habit worth building: when a product says polynucleotide, ask which one, at what molecular weight, at what concentration, and with what supporting data. Similar origins do not mean interchangeable materials.

• Which one? PDRN or PN, and does the supplier use the term consistently across the label, the data sheet and the sales deck?
• What molecular weight? A range, not a single word. If nobody can tell you, that is an answer in itself.
• What concentration? Milligrams per millilitre or ppm for a professional product; a percentage or position on the ingredient list for a retail one.
• What data? Is the evidence for this product, this fragment size and this route, or has it been borrowed from a different material in a different setting?

What this means in clinic

The topical products we supply are specified by their manufacturers as PDRN, and that is the language we use. The Krx Salmon DNA Meso Booster Ampoule is a salmon DNA ampoule used with microneedling and mesotherapy devices, and practitioners report using it for textural work and in the recovery phase after resurfacing. The ISOV PDRN Pink Energy HD Serum pairs PDRN with a ferment and algae base for daily use and for home care between sessions. Permatology's EXO-PDRN Recovery Ampoule is a two-step format with a freeze-dried PDRN powder reconstituted at the point of treatment, and the RegenBright PDRN Spicule Serum uses a spicule delivery system for brightening and renewal protocols.

When a client asks whether this is "the salmon DNA treatment", the answer is yes, followed by the specification. Which fraction, what concentration, what it is used for. Put that on the consultation sheet and the product shelf stops being a collection of similar-sounding words.

Browse the full range in our PDRN and regenerative collection, or read our guide to PDRN, exosomes and PLLA skin boosters.