Polynucleotide injections explained: evidence, risks and products

Polynucleotide injections are often compressed into the phrase “salmon sperm facial.” That description is memorable and medically unhelpful. The injectable does not contain sperm cells. It contains processed and purified chains of nucleotides—the repeating units from which DNA is built—formulated as a sterile product for injection.

The treatment sits between mesotherapy and regenerative medicine in the way it is marketed, but neither label proves an outcome. The useful way to assess it is to separate the material, the proposed biology, the injection procedure and the quality of the human evidence.

What exactly is being injected?

Most aesthetic PN products start with DNA obtained from salmonid fish such as salmon or trout. Manufacturing breaks that DNA into controlled chain lengths and uses purification and sterilisation to remove proteins, peptides and biological contaminants. The finished material is suspended in water or a gel; some products also contain hyaluronic acid or other excipients.

Polynucleotides are not:

• living cells or stem cells;
• exosomes;
• hormones or growth factors;
• gene therapy;
• a person’s complete DNA; or
• automatically the same formulation from one brand to another.

Human nucleases gradually break the chains down into smaller nucleotides, nucleosides and bases. They do not travel into cell nuclei and rewrite the patient’s genome.

How are polynucleotides supposed to work?

Three mechanisms are commonly proposed, with different levels of support.

A hydrated extracellular matrix

Long PN chains bind water and form a viscoelastic matrix. This can temporarily support hydration and the environment around fibroblasts. It is not the same as the predictable volumising behaviour of a cross-linked hyaluronic-acid filler.

Nucleotide salvage

Injured or metabolically active cells need nucleotides to build DNA and RNA. Breaking PN or PDRN down supplies bases and nucleosides that cells may reuse through salvage pathways, which require less energy than synthesising them from scratch. This is a plausible repair mechanism supported strongly by laboratory and wound-healing research, but cosmetic claims often extrapolate beyond the clinical data.

Adenosine signalling

PDRN research supports activation of adenosine A2A receptors, with downstream anti-inflammatory and tissue-repair signalling. That mechanism should not be copied automatically onto every PN gel. PN and PDRN differ in typical chain length, formulation and studied pharmacology, even though clinics and marketing often use the terms loosely.

 purified PN chains injected into superficial tissue
                         ↓
       water binding + gradual enzymatic breakdown
                         ↓
  extracellular support + reusable nucleotide building blocks
                         ↓
      proposed fibroblast and tissue-remodelling response

What does the clinical evidence actually show?

The evidence is encouraging but not mature.

A recent systematic review found nine aesthetic studies covering 219 patients. Several reported statistically significant improvements in wrinkles, texture or elasticity, and adverse effects were generally mild and short-lived. However, the studies varied in product, injection technique, treatment area, schedule and outcome measurement. Overall quality was low to moderate.

That has two consequences. First, it is reasonable to say PN may improve skin quality. Second, it is not reasonable to promise a specific percentage change, a universal three-session protocol or a fixed duration for every product.

A newer systematic review of randomised trials extends the evidence across skin rejuvenation, scar prevention and wound healing. It also shows why category-wide claims remain difficult: studies combine PN and PDRN, use different delivery methods and measure different problems. Evidence for wound healing is not automatically evidence for under-eye rejuvenation.

One randomised, patient- and evaluator-blinded split-face study compared a PN product with a polycaprolactone product around the eyes. Studies like this are more informative than before-and-after photographs, but a direct comparison of two active injectables still does not show how much either outperforms no treatment or a convincing placebo.

The most honest conclusion is promising for subtle skin-quality improvement, not proven for dramatic rejuvenation.

What happens during treatment?

After medical screening, cleansing and sometimes topical anaesthetic, a clinician places many small deposits into the superficial or mid dermis using a fine needle or cannula. Technique depends on the product and treatment zone. The face, periocular area, neck, décolletage and hands are common targets.

Small raised papules are expected with intradermal microdroplets. They may look like insect bites for several hours and sometimes a few days, especially around the eyes. Bruising and swelling depend as much on anatomy and injector technique as on the PN itself.

Clinics commonly propose two to four initial sessions separated by several weeks, then maintenance. This is a market pattern rather than one evidence-based schedule that applies to every brand. The manufacturer’s instructions for the specific syringe should determine concentration, depth, volume and interval.

What results are realistic?

Reasonable goals include a modest improvement in hydration, surface texture, fine crepiness and elasticity. Effects should develop over weeks rather than being judged from immediate post-injection swelling.

PN is a poor substitute when the actual problem is structural volume loss, a deep fold, marked tissue descent or dynamic muscle movement. Those concerns may be better matched to filler, biostimulatory filler, toxin, an energy device or surgery—each with its own risks.

Under-eye treatment deserves particular restraint. PN can be attractive because it adds less bulk than conventional filler, but it cannot remove a true fat pad, correct every tear-trough shadow or erase pigment caused by vessels or melanin.

Which injectable polynucleotide products are on the market?

This is a market map, not a ranking. Formulations, names and authorised uses can change by country. “CE marked,” “registered in Korea” and “FDA approved” are not interchangeable.

Product family	Manufacturer	Published format or positioning	Important distinction
Plinest / Plinest Eye / Newest	Mastelli, Italy	Plinest is commonly listed as PN-HPT 40 mg/2 mL; Eye as 15 mg/2 mL; Newest combines PN with hyaluronic acid	A family of different formulations, not one interchangeable syringe
PolyPhil / PolyPhil Eye (formerly PhilArt)	Croma-Pharma	PolyPhil: PN-HPT 40 mg/2 mL; Eye: 15 mg/2 mL	Eye and full-face versions differ in concentration and intended treatment zone
Nucleofill	Promoitalia, Italy	Soft Plus, Medium, Strong and other regional variants with different viscosity/concentration positioning	Product suffix matters; “Nucleofill” alone does not identify the formulation
Rejuran	PharmaResearch, South Korea	PN medical-device family; Rejuran S is supplied as a 1 mL syringe for temporary improvement of facial wrinkles	Healer, I, S and other regional products are not the same format

Other names encountered in European and UK clinics include Vitaran, Ameela/NUCLEADYN and Plenhyage. Presence at a wholesaler or clinic is not proof of the same evidence, composition or regulatory status as another PN product.

Before injection, the patient should be shown the unopened box and syringe. Check the exact product name, manufacturer, concentration, expiry date, lot number, tamper protection and local-language instructions. Counterfeit and grey-market injectables remove the traceability needed if something goes wrong.

How do PN, skin boosters, filler and PRP differ?

Treatment	What is delivered	Primary aim	Structural volume?
Polynucleotide	Purified DNA-derived chains	Skin quality and remodelling	Low and formulation-dependent
HA skin booster	Usually lightly cross-linked or non-cross-linked hyaluronic acid	Hydration and fine texture	Low
HA dermal filler	Cross-linked hyaluronic-acid gel	Shape, projection and volume replacement	Yes
PRP	Concentrated autologous platelets in plasma	Release of patient-derived signalling proteins	Minimal

“Skin booster” describes a treatment goal more than a single material. A PN/HA hybrid can legitimately sit in more than one column, which is why the ingredient list matters more than the clinic nickname.

What are the risks?

Common short-term effects include pain, redness, swelling, tenderness, itching, bruising and visible papules. These should settle rather than progressively worsen.

Less common but important risks include infection, prolonged inflammatory nodules, hypersensitivity, pigment change after inflammation and an unsatisfactory cosmetic result. Any needle or cannula used in the face can also injure a blood vessel. Although PN gels are not conventional high-volume fillers, anatomy-safe technique and an emergency plan still matter.

Seek urgent assessment for escalating pain, blanching or mottled colour, dusky skin, spreading redness, fever, pus, visual symptoms or neurologic symptoms.

Pregnancy and breastfeeding are usually excluded because adequate safety data are lacking. Active infection, inflamed skin, relevant immune disease, bleeding risk, previous severe injection reactions and fish allergy require product-specific assessment. Do not conceal anticoagulant or antiplatelet medication; the prescriber, not the patient, should decide whether anything changes.

How do you choose a practitioner and product?

Ask five concrete questions:

1. What exact product and formulation will be injected?
2. Is it legally supplied for injection in this country and traceable by lot?
3. Who is prescribing and injecting it, and what regulated qualification do they hold?
4. Why is this product suited to the actual diagnosis rather than simply available?
5. How will infection, allergy, nodules or suspected vascular injury be managed?

Avoid home injection. Sterility is only one problem; facial vascular anatomy, depth control, complication recognition and access to medical treatment cannot be learned from a product diagram.

What does regulatory status mean?

In Europe, injectable products without an intended medical purpose can fall under Annex XVI of the Medical Device Regulation and its common specifications. That framework addresses matters including risk management, biocompatibility, sterility and post-market surveillance. A CE mark is meaningful, but it is not a guarantee that every marketing claim has been proven in large clinical trials.

In the United States, no aesthetic injectable PN product was identified as FDA approved at the verification date. A product authorised elsewhere does not gain US approval by being imported, and describing it as “FDA registered” would not be equivalent to FDA approval.

Bottom line

Polynucleotides are neither magic salmon DNA nor obvious nonsense. They are a biologically plausible injectable material with a growing but still limited clinical evidence base. The best-supported expectation is a subtle improvement in skin quality after a series of treatments, not structural lifting or filler-like volume.

The category’s main weakness is not lack of interesting biology. It is the gap between broad regenerative marketing and small, heterogeneous human trials. Choose a traceable product, a medically accountable injector and a treatment plan built around the actual skin concern. Then judge the result with consistent photographs after swelling has resolved—not from the mirror the next morning.