PDRN consists of low–molecular-weight DNA fragments (often salmon-derived) with mechanistic plausibility through A2A receptor signaling and salvage pathways, yielding anti-inflammatory and regenerative effects when bioavailable.
Injectable polynucleotides have the strongest evidence, including split-face randomized data showing superior GAIS and roughness outcomes versus HA filler, and broad uptake in Korean aesthetic practice.
US regulatory constraints incentivize topical commercialization, since injectable PDRN is not FDA-approved for cosmetic use, while cosmetics can be marketed without premarket efficacy verification.
Stratum corneum barrier physics (500 Dalton rule) makes passive topical delivery implausible for PDRN-sized molecules; absent disclosed molecular weight, encapsulation, and in vivo delivery data, claims remain unsubstantiated.
Improvements attributed to topical PDRN are more plausibly driven by humectants/barrier-repair actives in the vehicle, with “injectable-equivalent” rejuvenation effects currently unsupported.
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Do topical forms of PDRN actually work or is it just a myth? Read more about the latest social media trend and learn how to counsel your patients in the clinic.
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From viral skin care hacks to trendy treatment devices, social media is shaping the questions patients bring into the exam room every day. In Dermatology Times’ new weekly series, Social Media Mythbusters, we break down trending claims clinicians are hearing in practice—exploring the proposed mechanism, what the evidence shows (or doesn’t), and whether each trend holds up under scrutiny.
In this edition, we’re examining topical delivery systems of polydeoxyribonucleotide (PRDN).
Have a social media trend you’d like us to investigate next? Send us the social media myths your patients are asking about, and we may feature them in an upcoming edition. Connect with us on our social media or email us at [email protected].
The Trend
PDRN, better known on social media as "salmon DNA,” is arguably one of the fastest-rising ingredients in prestige skin care over the last few years. K-beauty brands like Medicube and global luxury labels like Lancôme released PDRN-infused products, and awareness accelerated after celebrities like Jennifer Aniston and Kim Kardashian pushed the so-called "salmon sperm facial" into mainstream conversation. The global PDRN skincare market is expected to record a valuation of $811.4 million in 2035, at a CAGR of 9.7%. Serums, creams, and masks have grown to over 60% share of that market, with total online search volume for PDRN growing daily.1
The social media narrative is consistent and compelling. PDRN is the ingredient that powers the "glass skin" transformations seen at elite Korean clinics, now available in a serum on your bathroom shelf. As with several previous entries in this series, the truth is considerably more stratified. The underlying science of PDRN is genuinely impressive: the gap between that science and what a topical consumer product can deliver is precisely where dermatologists need to intervene.
PDRN is a purified mixture of low-molecular-weight DNA fragments acquired from Oncorhynchus mykiss (salmon trout) or Oncorhynchus keta (chum salmon) sperm DNA. Salmon DNA is used not for any mystical reason but because its DNA shares structural similarities with human DNA—specifically, a high degree of sequence homology that facilitates molecular compatibility. Newer versions are being developed through biotechnology, often derived from plants like ginseng, or through microbial fermentation. Biologically, PDRN exerts its effects through two converging pathways: A2A adenosine receptor activation and the salvage pathway. These reduce pro-inflammatory cytokines and accelerate tissue regeneration. The mechanistic case is not in dispute. What is in dispute is how this mechanism is accessed and at what scale, depending on the delivery method.
📊 POLL: Which brand's viral PDRN products have patients been asking about the most?
The Evidence
The injectable evidence base is where the clinical legitimacy of PDRN rests, and it is substantially stronger than social media's pivot to topical products acknowledges. In a randomized split-face clinical trial involving 27 participants, Rejuran (a polynucleotide injectable) was compared with an HA filler. The PDRN/PN-treated side showed significantly higher Global Aesthetic Improvement Scale (GAIS) scores at 16 weeks and a greater reduction in skin roughness by week 28.2 Rejuran is the only commercial PN product in Korea allowed for direct skin injection and is among the most widely used skin boosters in Korean aesthetic practice.3 But in the US, the regulatory picture is starkly different.
Is There Any Clinical Evidence for Topical PDRN?
A late-2025 clinical study on low-molecular-weight peony PDRN showed improved periorbital skin elasticity after 4 weeks of topical use, making this the first published topical clinical evidence for any form of PDRN. This is a meaningful development and warrants acknowledgment: the delivery problem is not necessarily permanent, and low-molecular-weight plant-derived PDRN analogs represent a genuinely different category from standard salmon-derived PDRN in terms of potential topical bioavailability. However, there are several caveats:
This is a single small study using a specific low-MW plant-derived PDRN that is not representative of the majority of products on the market
Periorbital elasticity improvement over 4 weeks in a single trial is a modest and preliminary finding
The regulatory and commercial frameworks for disclosing whether a product contains this formulation versus standard PDRN do not currently exist at the consumer level
In the US, injectable PDRN is not FDA-approved for cosmetic use. Without FDA approval, there is no federal verification of safety, efficacy, or quality standards for these treatments. Topical PDRN—found in serums, creams, and ampoules—is legally sold in the US as a cosmetic product, but as we know, cosmetics do not require FDA approval before sale, as long as no medical claims are made. This is the structural context that explains why the entire US PDRN skin care market is built on topical products: the clinical procedure that generated the compelling results is not legally available, so manufacturers are selling the ingredient in a format that doesn't require regulatory approval but also doesn't deliver the ingredient the same way. This is the most important piece of information your patients are not getting from any influencer video, and it is the structural reason why the entire PDRN serum category warrants scrutiny.
The stratum corneum's selective permeability is governed by a well-established biophysical principle: the quantitative expression of the stratum corneum barrier is the widely cited 500 Dalton rule, which states that molecules larger than approximately 500 Daltons are unlikely to penetrate intact human skin through passive diffusion. PDRN fragments range from 50 to 1,500 kilodaltons.4 Thus, PDRN applied topically without an active delivery mechanism is unlikely to reach the fibroblasts in the viable dermis where its adenosine A2A receptor targets reside. Most brands do not disclose their PDRN molecular weight, encapsulation method, or any in vivo data demonstrating dermal delivery. The regulatory environment for cosmetics does not require this disclosure. Patients buying an expensive “PDRN serum” from a K-beauty brand are almost certainly applying an ingredient that sits on the skin surface rather than reaching its cellular targets—regardless of the mechanism described on the bottle. The "microneedling in a bottle" framing is misleading; claims that topical PDRN serums are equivalent to the injectable clinic procedures that generated the clinical data are not supported.
Without the robust topical penetration, what benefits might a patient realistically expect from a PDRN serum? The honest answer is that any benefit is likely to come from co-formulated ingredients (hyaluronic acid, glycerin, niacinamide, peptides, ceramides, etc.) rather than from the PDRN molecule reaching its intracellular targets. The PDRN fraction itself may offer modest surface hydration and some superficial anti-inflammatory signaling at the stratum corneum level, but these are not the collagen-stimulating, tissue-regenerating effects the injectable literature documents. So, patients who report visible improvement after starting a PDRN serum are not necessarily imagining it; they may simply be attributing the result to the wrong ingredient.
Is this a myth? Yes, but there is some truth to it!
The evidence base for injectable PDRN shows consistent improvements in skin texture, dermal thickness, elasticity, and wrinkle depth via a well-characterized A2A receptor mechanism. This is genuine science, not a marketing narrative. But the topical consumer category is a different matter. Standard-molecular-weight PDRN applied in a serum does not penetrate to the dermal fibroblasts where its targets reside. Most brands making PDRN claims are not disclosing the molecular weight, encapsulation method, or topical delivery data that would be necessary to evaluate whether the product does what the mechanism promises.
The verdict for topical PDRN is therefore honest uncertainty rather than confident dismissal: the ingredient's biology is real, the delivery problem is real, and the evidence that any specific commercial product has solved the delivery problem sufficiently to produce the injectable-scale effects social media depicts does not yet exist. Patients looking for measurable dermal changes and rejuvenation should be directed toward the clinical procedure itself rather than a topical surrogate that cannot currently demonstrate equivalent delivery.
The Script
If a patient comes in asking if their PDRN serum actually works, here are some important points to hit:
Explain the science clearly: PDRN does have some proven regenerative benefits, but the outer layer of your skin will not absorb the large molecule, despite marketing claims.
Attribute results to other ingredients: If there are noticeable improvements in the skin after PDRN serum use, it’s most likely due to other ingredients in the formulation.
Separate the serums from the injectables: Improvements in skin texture, elasticity, and wrinkles have been shown in the procedural technique, not the topicals— but it is not FDA-approved in the US and is only used off-label.
Give proper guidance on product purchases: Expensive ampoules and creams may be unnecessary, especially if they don’t disclose molecular weight, delivery technology, and clinical data.
2. Lee YJ, Kim HT, Lee YJ, et al. Comparison of the effects of polynucleotide and hyaluronic acid fillers on periocular rejuvenation: a randomized, double-blind, split-face trial. J Dermatolog Treat. 2022;33(1):254-260. doi:10.1080/09546634.2020.1748857
3. Rho NK, Han KH, Cho M, Kim HS. A survey on the cosmetic use of injectable polynucleotide: The pattern of practice among Korean Dermatologists. J Cosmet Dermatol. 2024;23(4):1243-1252. doi:10.1111/jocd.16125
4. Squadrito F, Bitto A, Irrera N, et al. Pharmacological Activity and Clinical Use of PDRN. Front Pharmacol. 2017;8:224. Published 2017 Apr 26. doi:10.3389/fphar.2017.00224
