The first thing to settle about polynucleotides is not mechanism or technique. It is that no injectable polynucleotide product is FDA-approved or FDA-cleared in the United States. Searches of FDA’s drug-label and 510(k) databases under “polynucleotide” and “polydeoxyribonucleotide” return no match. Rejuran®, Plinest® and the other names patients bring in are not approved here.
So this is an unapproved category in the United States, not an off-label one. Off-label means using an FDA-approved product outside its labeled indication, a recognized part of practice; unapproved means no US approval exists for the product at all, and no FDA pathway authorizes importing a non-approved injectable for a patient.
Providers get asked anyway, because PN injectables are ordinary practice in Korean and Italian clinics and across Europe, and because periocular before-and-after content travels faster than regulatory nuance. Here is the category as it stands, within Empire’s look at how Korean aesthetic practice is influencing US clinics.
Unapproved, not off-label: what that means in practice
With no US label there is no approved indication, no approved route, and no FDA-reviewed safety summary to hand a patient. Product obtained outside the approved supply chain carries no assurance of identity, purity or lot traceability, and the clinician who injects it owns that gap.
Note what unapproved does not mean. It is not a finding that the material is unsafe or ineffective: FDA has not evaluated these products, which differs from evaluating and rejecting them. The usable answer to a patient is the accurate one: this is used abroad, it is not approved for injection here, and here is what we can offer toward the same goal. Providers are having that conversation about exosomes already, where enforcement is further along — see the regulatory analysis of exosome products.
What a polynucleotide actually is
In aesthetic medicine, “polynucleotide” means a purified mixture of DNA fragments from fish germ cells — chum salmon (Oncorhynchus keta) and rainbow trout (O. mykiss). Sperm cells are used because, per the manufacturing literature, spermatozoa provide highly purified DNA with limited risk of impurities. The result is injected as a viscous solution, not a shaped gel.
Fragment length is the defining variable. A 2025 review in Biomolecules proposed a working cutoff at 1,500 kDa: polydeoxyribonucleotide (PDRN) below it, historically 50–1,500 kDa, and polynucleotides (PN) at or above it, with recent patents describing material in the 2,000–10,000 kDa range. A 2025 comparison in Pharmaceutics describes PN as forming a more porous, highly viscous, three-dimensional structure, while PDRN consists of relatively shorter oligonucleotide sequences.
You will also see “PN-HPT” (polynucleotides highly purified technology) used as if it were a class. It is not: it is one Italian manufacturer’s trademarked purification process, and its purity claims are marketing.
The molecular-biology meaning of the word
Many searches for “what is a polynucleotide” are not clinical. In molecular biology it is any chain of nucleotides joined by phosphodiester bonds, which makes DNA and RNA polynucleotides — correct, and nothing to do with an injectable product. Confirm which meaning is in play before answering.
Polynucleotides vs PDRN: molecular weight and product class
PDRN and PN are two fractions of the same starting material, not two different drugs: same source tissue, same extraction lineage, different molecular-weight window and therefore different rheology. That single fact explains most of the market confusion, including product pages that use the terms interchangeably.
Regulatory class, by contrast, diverges sharply by market. PDRN has a long pharmaceutical history in Italy, where Placentex was approved as a drug in 1994 for dystrophic and dystrophic-ulcerative connective tissue disorders. In Korea, PDRN preparations are pharmaceuticals while the higher-molecular-weight PN injectables are regulated as medical devices. In the European Union the PN injectable Plinest® is a class III CE-marked medical device, not a licensed medicine. In the United States neither class has a drug label or a clearance.
One figure worth correcting, because it circulates in vendor decks: the commercial PDRN injectable ampoule contains 5.625 mg of polydeoxyribonucleotide in 3 mL, which is 1.875 mg/mL. The commonly repeated “5.625 mg/mL” is a threefold overstatement, so check whether a foreign label’s figure is per ampoule or per milliliter. Empire’s PDRN reference page goes deeper, and the topical and microneedling side of the same chemistry is covered in salmon-DNA microneedling and what salmon-derived DNA does in skin.
Is it actually a biostimulator?
The category is marketed as a next-generation biostimulator, and the label is loose enough to mislead. A crosslinked hyaluronic acid filler is a shaped gel engineered for lift. Poly-L-lactic acid, as in Sculptra®, and calcium hydroxylapatite, as in Radiesse®, are particulate biostimulators: a carrier places particles that provoke a controlled host response and collagen deposition over months. Polynucleotides are neither — a non-crosslinked, non-particulate solution meant to alter skin quality, not build structure. Expecting contour from PN is a category error, as is expecting a particulate biostimulator’s durability.
The overlap is intent: treating tissue rather than filling it, the same logic behind skin boosters compared with volumizing fillers and biostimulator injections.
The proposed mechanism, and why “proposed” is the right word
Two pathways are described in the review literature. The first is adenosine A2A receptor agonism, in which degraded nucleotides are proposed to decrease inflammation and stimulate cell migration and growth, angiogenesis and extracellular matrix maturation. The second is nucleotide salvage, in which recycled nucleotides are proposed to support fibroblast production of collagen, elastin and fibronectin.
Each is a hypothesis built largely on preclinical work; human mechanistic confirmation is not established. The most-cited PDRN pharmacology review also carries a corrigendum stating that its conflict-of-interest statement was incorrectly filed and patent disclaimers omitted: several authors are co-inventors on PDRN patents and one received manufacturer research support. That does not make the mechanism wrong, but the foundational account was written substantially by people with a commercial stake in it — exactly when a clinician says “proposed” rather than “proven.”
The retracted literature, and what it does and does not tell us
This part rarely appears in a product presentation. A PubMed search restricted to retracted publications returns five records across polynucleotides and PDRN — three clinical studies, one narrative review, one animal study — and the two that matter most are the two cited most.
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The first is the phase III randomized, double-blind, matched-pairs trial comparing a polynucleotide filler with a hyaluronic acid filler for crow’s feet, published in the Journal of Korean Medical Science in 2014 with 72 patients, and retracted in February 2016. The stated reason was conflict of interest: the manufacturer funded the trial, a coauthor’s employment at the company’s R&D center was not disclosed, and the funding sponsor was incorrectly identified. Separately, its own result was null — no statistically significant difference between groups on the primary or secondary efficacy outcomes. It is routinely called the pivotal trial for the category; it is neither pivotal nor available.
The second is the 218-participant randomized, participant- and evaluator-blinded, matched-pair study comparing a polycaprolactone filler with a polynucleotide filler for crow’s feet, published in the Journal of Cosmetic Dermatology in 2025 and retracted on March 16, 2026, for product misidentification: the comparator was described as pegylated polycaprolactone when it contained pure polycaprolactone. Because those materials differ in biocompatibility, viscosity and biodegradation profile, the notice concluded the error undermines the reliability of the findings.
The other three: a 2022 cohort of 40 women using PN-HPT® in the facial middle third, retracted in January 2024 over duplicated figure panels that did not show patients before and after treatment as reported; a 2024 narrative review on skin boosters, retracted in November 2025 for insufficient peer review and uncited images; and a 2015 rat study of PDRN, retracted in 2026 over figure integrity.
Be precise about what this means. Retractions for undisclosed funding, duplicated figures and a misidentified comparator are findings about how those studies were conducted and reported. They are not evidence that polynucleotide injection does not work — a retracted trial tells you nothing about the treatment in either direction. What they tell you is that the top of this category’s citation pile is thinner than it looks, that manufacturer entanglement is documented rather than hypothetical, and that a provider sold on “strong published evidence” should ask which papers and check their status. Not “debunked” — “less evidence than advertised.”
What the surviving evidence supports
Set those aside and the remaining human evidence is small and modest in quality. The largest synthesis, a 2025 systematic review in the Journal of Cosmetic Dermatology, found nine studies of low and moderate quality covering 219 patients treated with PN: promising outcomes for wrinkles, texture and elasticity, limited consensus on optimal use, and a call for rigorous studies. One coauthor also authored retracted PN work.
The controlled studies read better individually than pooled. A randomized, double-blind, split-face comparison of PN with an HA product in 27 patients found no significant difference between sides on visual analog and global aesthetic improvement scales, while instrument measures of elasticity, hydration, roughness and pore volume favored PN. A split-face, double-blind randomized study in 30 patients with melasma found that adding PN to microneedle radiofrequency gave no statistically significant difference versus the device alone. An open-label study in 17 patients with acne scars did favor a botulinum-plus-PDRN combination over either agent alone, but it was unblinded and tiny.
The through-line: across non-retracted controlled studies, PN and PDRN tend to improve instrument-measured skin-quality parameters while repeatedly failing to beat an active comparator or an untreated side on blinded global aesthetic scales. A real but narrow signal.
The periocular use case
Most search interest here is periocular, and the rationale is sound in principle: that skin is thin and mobile, tolerates volumizing gel poorly, and suits a skin-quality intervention better than a structural one. But the best evidence there is the 27-patient split-face study above, and the durability trial is retracted. The region generating the demand is where the evidence is weakest — and in the United States you cannot legally treat it with this product class.
Frequently asked questions
What is a polynucleotide?
In molecular biology, any chain of nucleotides linked by phosphodiester bonds — DNA and RNA included. In aesthetic medicine it is narrower: a purified, molecular-weight-selected preparation of salmon- or trout-derived DNA fragments, injected to target skin quality rather than volume.
How do polynucleotides work?
Two proposed pathways: adenosine A2A receptor agonism, described as reducing inflammation and supporting cell migration, angiogenesis and matrix maturation; and nucleotide salvage, proposed to supply fibroblasts with material for collagen, elastin and fibronectin. Both are hypotheses from largely preclinical work.
Are polynucleotides FDA-approved?
No. There is no FDA-approved injectable polynucleotide drug and no cleared polynucleotide device; drug-label and 510(k) searches return no match for either term. The category is unapproved here rather than off-label, and no FDA pathway authorizes importing a non-approved injectable.
What is the difference between polynucleotides and PDRN?
Molecular weight and, in some markets, regulatory class. Both come from purified salmon or trout DNA; PDRN is the fraction below the proposed 1,500 kDa cutoff, PN the more viscous fraction above it. In Korea, PDRN products are pharmaceuticals and PN injectables devices; here neither is approved.
How long do polynucleotides last?
No durability figure can be defended from the surviving literature: the one trial designed to compare durability head to head with an HA product is retracted, and the remaining controlled studies are short-term with heterogeneous endpoints. A specific “lasts X months” claim is marketing, not a measured result.
What are the side effects of polynucleotides?
Published reports describe mainly local, injection-related effects, but the safety database is small and short — not a mature profile. The larger US-specific risk is structural: no approved product means no label, no verified supply chain, no accountability. A case report of intradermal necrosis and permanent atrophic scarring after injection of an exosome product labeled for topical use only is the cautionary parallel.
Where to learn this properly
What a US provider can actually train on and use is PDRN and the combinations around it. Empire’s Facial Contouring Injectables: Sculptra®, Radiesse®, Exosomes & PDRN Certification Workshop is a hands-on course covering preparation, dilution and injection technique for poly-L-lactic acid and calcium hydroxylapatite; integration of exosome therapy and PDRN into facial and skin rejuvenation protocols; layering strategies with PDO threads, PRP and PRF; cannula and microcannula technique across the cheeks, jawline, temples, nasolabial folds, chin, neck and décolletage; and complication management. It is open to MD/DO, DMD/DDS, NP, PA and RN attendees, and is non-CME.
On the didactic side, Module 9 of Empire’s Peptide Therapy Certification curriculum covers PDRN and polynucleotide skin protocols alongside exosome products and their current US regulatory posture. For the whole regenerative shelf, see exosomes, PDRN and PRP compared.
