Polynucleotides (PDRN and PN) in HOF: What They Are

Polynucleotides are chains of nucleotides, the units that make up DNA, purified for use in health and aesthetics. In orofacial harmonization they appear under two acronyms, PDRN (polydeoxyribonucleotide) and PN (polynucleotides), and are discussed as a class aimed at skin quality, alongside the skin booster and biostimulators. On social media the topic circulates under the nickname "salmon DNA" or "salmon sperm," because of the most common source of the raw material.

This guide explains what the class is, what sets it apart from other products, what is known about the evidence and, above all, what to check in the regulatory status before any indication. It names no brands and covers no technique. The decision belongs to the qualified professional, according to the rules of their professional board in Brazil.

Where do they come from and how are they described?

The polynucleotides used in aesthetics are extracted, in most products, from the reproductive cells of fish in the salmon family, such as trout and chum salmon. These cells are chosen for purity: the extraction and purification process aims for DNA free of proteins and other contaminants, which lowers the risk of an immune reaction.

The mechanism described in the literature follows two main paths:

• Repair signaling. The DNA fragments act on adenosine receptors (especially A2A), with a described effect of modulating inflammation and stimulating vessel formation and fibroblast activity.
• Nucleotide salvage pathway. The fragments supply "building blocks" that cells reuse to synthesize DNA in tissue that is being repaired.

The oldest clinical use of the substance is not aesthetic: it was studied in wound healing, ulcers and skin grafts. The application to skin quality came later.

What is the difference between PDRN and PN?

The two acronyms appear as synonyms in commercial content, but they usually refer to different products.

The boundary between the two is not standardized across manufacturers. Molecular weight, concentration and carrier vary, and what you read about one product cannot be transferred to another. What counts is what is in the registration and instructions of the product in your hands.

Polynucleotides, skin booster or biostimulator?

All three are indicated for "skin quality," which causes confusion in the clinic and in the patient's search.

Some products combine polynucleotides with hyaluronic acid, which often shows up in searches as "skin booster with PDRN." In those cases, the regulatory classification and approved indication depend on the product as a whole, not on each component. For an overview of biostimulators, see the biostimulators overview.

What does regulation say in Brazil?

This is the point that weighs most on the indication. In 2025, CRM-PR Opinion No. 2936/2025, on the use of PDRN, recorded that products containing the substance found in the ANVISA database (Brazil's health regulator) were registered as cosmetics, for topical use only, and that injectable use was not provided for. The same opinion concluded that injectable treatment still needed more scientific evidence.

A cosmetic, under health law, is a product for external use. A product registered in that category has, by definition, no approved indication for injection. Fillers and aesthetic injectables, by contrast, are registered as high-risk or maximum-risk medical devices, or as medicines, with a different kind of evaluation.

Using a product outside what its registration provides brings health, ethical and legal risk, and weakens the professional's defense in the face of any complication. ANVISA's campaign on safe procedures sums up what the patient should check: an authorized place, an authorized product and a qualified professional.

What is known about the evidence?

Most studies of polynucleotides in aesthetics have small samples, short follow-up and often manufacturer involvement. The reported results tend to be favorable for hydration, elasticity and the look of fine lines, with a good reported safety profile, but that does not yet equal the volume of evidence available for hyaluronic acid or botulinum toxin.

In practice, this means:

• There is no basis for promising the patient a specific result.
• Direct comparison with the skin booster or biostimulator is still little studied.
• The number of sessions and the intervals vary between manufacturer protocols and are not standardized.

For which concerns does the topic usually come up?

The concerns that lead patients to ask about polynucleotides are about skin quality, not volume:

• Thin, dull skin around the eyes, often confused with the concern about under-eye hollows.
• Fine lines and uneven texture.
• Acne scars.
• "Tired" skin without evident volume loss.

In all of them, the first question is diagnostic: is the concern about volume, pigment, vessels or skin quality? If it is volume, another tool solves it better. If it is skin quality, the options registered for the intended use come into the conversation.

How do you talk about this with the patient and in advertising?

Patients often arrive with information from social media, sometimes with strong promises. An honest answer covers the source, the still-limited evidence and the regulatory status. Any skin quality treatment should have specific informed consent; a starting point for this family of procedures is the skin booster consent form template, to be adapted to the product and reviewed with a lawyer and your professional board's rules.

In advertising, the general rules apply: no promises of results and no advertising of use not covered by the product's registration. See what you can advertise under CFO and CONAR rules. For pricing skin quality procedures, the cost-per-session logic is in pricing a skin booster.

And in Harmy?

Harmy's projection works with volume in ml per area and changes only the marked areas. The prompt prohibits skin retouching, makeup and lighting changes, so improvement in texture, glow or hydration is not something the simulation represents. Polynucleotides, like the skin booster, fall outside what the projection shows. When the plan combines volume with skin quality, the projection illustrates the volume part and explaining the skin part is up to you.

Checklist before considering polynucleotides

1. Concern classified: volume, pigment, vessels or skin quality.
2. Product registration checked with ANVISA: category, route of use and indication.
3. Practice within your professional board's rules confirmed.
4. Medical history that asks about allergy to fish and fish proteins.
5. Patient informed of the source, the still-limited evidence and the absence of any promise of results.
6. Specific informed consent signed.
7. Standardized before photos and a record of product, lot and date.