Polynucleotide Injections (PN): What Does the Evidence Actually Show?

Part of: Fillers & injectables

What "salmon DNA" injections mean, how PN differs from PDRN, what they may improve, the limits of the evidence and safety, and when they are a reasonable choice.

Aesthetics · 2 min read · October 6, 2026

Written and medically reviewed by Dr. Yousef Abo Zarad · German board-certified dermatologist · Last reviewed: October 2026

The short answer

"Salmon DNA injections" is a popular patient term for some DNA-derived injectables, including polynucleotides (PN). Unlike conventional volumizing fillers, the main goal is generally skin-quality improvement rather than adding facial volume.

The evidence is promising but not definitive: studies are small, products and protocols vary, and there is no single regimen established as best for everyone.

What exactly are they?

  • "Salmon DNA injections" is a popular term, not a scientifically precise umbrella. For fish-derived products the more exact name is polynucleotide (PN) injections.
  • PN and PDRN are both derived from DNA fragments, but they are not names for exactly the same material. Chain length, molecular weight and some proposed mechanisms differ, so studies on PDRN cannot be pooled as direct evidence for every PN product, and the reverse.
  • Rejuran is a brand, not a synonym for PN.
  • Not every PN or PDRN product is salmon-derived. Non-animal and plant-derived materials are being studied, and source and formulation vary by product.
  • Regulatory classification and approved indication vary by product and country, so there is no universal "FDA-approved" or "approved for rejuvenation" statement.

What may they improve?

  • Small clinical studies and reviews suggest PN may improve aspects of fine wrinkles, texture, elasticity and hydration, and patient-reported skin quality.
  • Around the eyes, studies suggest a potential benefit for fine lines and skin quality, but they do not prove PN corrects every cause of dark circles, hollowness or eye bags. See the under-eye PN answer.
  • They are not "stem cells", "regenerating DNA", "rebuilding the face", collagen replacement or a facelift substitute.
  • No promise is made for pigmentation or melasma, acne scars, pores, hair loss or wound healing.

What to do before deciding: are they worth it?

PN may be reasonable for a patient seeking a gradual skin-quality improvement who understands that the evidence base is still less mature than for some established treatments.

It is not a substitute for treatment of substantial volume loss, mechanical laxity or another problem with a more direct evidence-based option. Start with the diagnosis, not the trend. To compare skin-quality injectables, see skin-quality injectables: which type suits you?.

What about safety?

  • Injection-related discomfort or pain can occur, and temporary injection-site reactions are possible.
  • Available small trials and reviews report mostly mild, transient adverse effects and few serious treatment-related events, but the samples are too small to call the treatment risk-free.
  • Product quality, sterility, regulatory status, injection technique, allergy and source considerations, and the anatomic site all matter.

What are the limits of the evidence?

The strongest recent syntheses remain cautious: studies are few and small, and products, protocols and measured outcomes differ. This supports a possible benefit, but not certainty about the ideal product, dose, interval, number of sessions or long-term durability. So no fixed number of sessions or fixed duration is given here.

When do you need a doctor?

  • Before injection, to define the main problem: skin quality, volume or laxity.
  • Ask about the product, its source and its regulatory status in your country, and about any previous allergy.
  • If your concern is only the under-eye area, start with the dedicated answer.

Medical Evidence

Keep reading on this topic