How Salmon Sperm Conquered Skincare
Yes, you read that correctly. The hottest ingredient in K-beauty right now is derived from salmon reproductive cells. Polydeoxyribonucleotide, mercifully abbreviated to PDRN, consists of purified DNA fragments extracted from salmon or trout sperm. And it's absolutely everywhere: pink-tinted serums, ampoules, essences, and creams with names like "Salmon DNA Glow" flooding Sephora, Amazon, and Olive Young shelves.1
The PDRN skincare market is projected to grow from $321 million in 2025 to over $811 million by 2035. Injectable polynucleotides, led by Korea's Rejuran brand, have been standard in Korean dermatology clinics since 2014. But in 2025-2026, the trend crossed over: from clinical injections to over-the-counter topicals, from Seoul to everywhere.2,3
The marketing narrative is compelling: PDRN is DNA that's remarkably compatible with human tissue. It activates your skin's repair pathways, stimulates fibroblasts, boosts collagen, and promotes regeneration from the cellular level up. It's been used in wound healing for over 20 years. What's not to love?
The answer: the product most people are actually buying may have very little to do with the science most people are citing.
What PDRN Is and How It Works (When Injected)
PDRN is a mixture of DNA fragments ranging from 50 to 1,500 kilodaltons, extracted from salmon (Oncorhynchus keta) or trout (Oncorhynchus mykiss) sperm cells and purified through extensive processing to remove all proteins, lipids, and cellular debris. The result is pure polynucleotide chains that are biocompatible with human tissue.4,5
The primary mechanism of action involves the adenosine A2A receptor. When PDRN fragments bind to these receptors on cell surfaces, they trigger anti-inflammatory signaling and stimulate VEGF (vascular endothelial growth factor) expression, promoting angiogenesis and tissue repair. There's also a secondary "salvage pathway" mechanism: cells can recycle the nucleotide building blocks from PDRN fragments to support DNA synthesis and repair.4,5,6
In skin, this translates to: increased fibroblast proliferation, elevated collagen and elastin production, enhanced wound closure and re-epithelialization, anti-inflammatory effects, and improved microcirculation. The preclinical evidence for these effects is substantial, spanning decades of in vitro and animal studies.5,6
I want to be precise here: the wound-healing science behind PDRN is legitimate. Where the story breaks down is not in the biology. It's in the delivery.
Dr. Maren ColeIt's important to distinguish between two related but different molecules. PDRN (polydeoxyribonucleotide) consists of shorter, lower-molecular-weight DNA fragments and primarily works via adenosine A2A receptor activation. PN (polynucleotide) consists of longer, higher-molecular-weight DNA chains that are more viscoelastic and provide structural support when injected. Rejuran is technically a PN product. Many topical "PDRN" products don't specify which they contain.7,8
What Works When You Skip the Skin Barrier
The evidence for injectable PDRN/PN is where the real substance lives. And it's worth understanding, because this is the science that topical products are borrowing credibility from.
What they did: Randomized, double-blind, split-face trial comparing injectable Rejuran (PN) versus hyaluronic acid filler for periocular rejuvenation.
What they found: PN injections produced significant improvements in skin texture, wrinkle depth, and elasticity comparable to HA. Additionally showed dose-dependent collagen synthesis, unlike HA which doesn't stimulate collagen production.9
Context: Small sample but strong design (split-face, double-blind). This is injectable, not topical.
What they did: Systematic review across Embase, Medline, and Cochrane of all primary research on PN in aesthetic medicine from 2010-2024.
What they found: PN injections showed "promising outcomes in reducing wrinkles, improving skin texture, and enhancing elasticity, with statistically significant results in several studies." However, the review explicitly noted that all 9 included studies were of low to moderate quality.10
Critical detail: Only 219 total patients across 9 studies. The review called for "large, high-quality RCTs with standardized endpoints." This is the best available synthesis, and it found the evidence base thin.
What they found: A survey of Korean dermatologists published in J Cosmet Dermatol documented widespread clinical use of injectable PN, with practitioners reporting consistent patient satisfaction for skin texture, elasticity, and overall quality improvement.11
Limitation: Practitioner surveys capture clinical impressions, not controlled outcomes. Still, the breadth of real-world use in Korean dermatology is notable.
Key conclusion: A 2024 systematic review evaluating the scientific basis for PDRN "revealed several shortcomings" and called for standardization of doses, delivery methods, safety profiles, drug interactions, sourcing, extraction, and storage before PDRN can be considered a "therapeutic agent with established quality and reliability."12
Why Your Topical Serum Faces a Physics Wall
Here is the part that most reviews gloss over and most marketing departments ignore entirely.
The skin's stratum corneum functions as a molecular bouncer. As a general rule, molecules larger than 500 daltons have significant difficulty crossing this barrier. This is known as the "500 Dalton rule" and it's one of the most fundamental principles in topical drug delivery.13
PDRN molecules range from 50,000 to 1,500,000 daltons.
Read that again. The smallest PDRN fragments are 100 times larger than the skin barrier cutoff. The largest are 3,000 times larger. This is not a subtle gap. It's a physics wall.
The size problem, visualized. Circles are roughly proportional to molecular weight. The skin barrier blocks molecules over 500 daltons. PDRN ranges from 50,000 to 1,500,000 daltons. Some Korean brands now process PDRN into nano-sized fragments, but evidence for meaningful dermal penetration of topical formulations remains extremely limited.13,14
Some brands address this with nano-processing, encapsulation, or liposomal delivery systems. These are legitimate formulation strategies that can improve penetration. But here's the critical detail: virtually no published clinical trials have tested topical PDRN products on human skin for anti-aging outcomes. The studies people cite are overwhelmingly about injectable PDRN in wound healing contexts.14,15
The injectable evidence is borrowed credibility. There is almost no published data demonstrating that a topical PDRN serum produces the same regenerative effects as an injection that bypasses the skin barrier entirely.
Dr. Maren ColeDermatologist Dr. Rachel Ho put it directly: "I don't believe topical PDRN replicates the benefits of injections like reducing scar depth or wrinkles. However, it can be valuable for barrier repair and post-treatment healing." YouTuber and dermatologist Dr. Dray was blunter: "I'm highly doubtful these products do anything beyond moisturize the skin."14
The Evidence Bait-and-Switch
Marketing cites injectable/wound-healing studies to sell topical serums. The delivery method, concentration, and context are completely different. A topical product sitting on the stratum corneum is not the same as PDRN injected directly into the dermis.14,15
No FDA Approval
Injectable PDRN is not FDA-approved in the U.S. for cosmetic use. Topical PDRN is sold as a cosmetic (no efficacy review required). Rejuran is approved only in South Korea and some European markets. The Philippines FDA has issued warnings against unregistered products.3,16
Concentration Opacity
Products advertise "99% PDRN" or "100,000 ppm," but these numbers can be misleading. They often refer to the concentration of a diluted PDRN solution, not pure active. Brands rarely disclose actual PDRN concentration in the final formula in a way that's comparable to clinical studies.14
What Topicals Probably Do
Topical PDRN likely provides surface-level hydration, mild barrier support, and soothing effects, particularly when formulated alongside proven ingredients like niacinamide, ceramides, and hyaluronic acid. These are real benefits. They're just not "cellular regeneration."14,15
The microneedling exception. One scenario where topical PDRN may deliver more than surface effects: when combined with microneedling, which creates temporary channels through the stratum corneum. Some clinics offer "salmon DNA facials" combining PDRN serums with microneedling. This approach has theoretical merit but hasn't been studied in controlled trials for this specific combination.15
Two Different Products, Two Different Verdicts
This is a story of two products wearing the same name. Injectable PDRN/PN has a legitimate scientific foundation: a well-characterized mechanism (adenosine A2A receptor activation), decades of wound-healing data, and a growing body of small aesthetic trials showing real improvements in skin texture, elasticity, and wrinkle depth. The evidence isn't robust yet, as the systematic reviews themselves acknowledge, but there's enough there to call it promising. If you have access to a qualified practitioner and injectable PN is available in your market, the clinical rationale is reasonable.
Topical PDRN serums are a different story entirely. The molecular size problem is real and largely unaddressed by the marketing. There are virtually no published clinical trials demonstrating anti-aging efficacy for topical PDRN formulations applied to intact skin. The evidence being cited to sell these products was generated using injections, not serums. What you're likely getting is a well-formulated hydrating product, not cellular regeneration.
If you want PDRN benefits: Ask a dermatologist about injectable options if they're available in your region. For topicals, understand that you're buying a hydrating serum with an interesting ingredient, not a regenerative treatment. Your money is better spent on retinoids, vitamin C, and sunscreen if anti-aging is your primary goal.
If you love the product anyway: That's fine. Hydration and barrier support are genuinely valuable. Many PDRN serums are well-formulated with niacinamide, ceramides, and hyaluronic acid. Just don't pay a premium for the salmon DNA specifically, because the evidence that topical PDRN adds meaningful regenerative benefit beyond those companion ingredients simply doesn't exist yet.
Injectable PDRN/PN has legitimate wound-healing science and promising (though limited) aesthetic evidence. Topical PDRN serums face a fundamental molecular size barrier: PDRN molecules are 100-3,000x larger than what skin typically absorbs. Until clinical trials demonstrate that topical formulations can replicate injectable results, the $25 salmon DNA serum is likely an expensive moisturizer borrowing credibility from a different product category.
Sources
- Various K-beauty and skincare trend reports. PDRN identified as breakout ingredient of 2025 across Refinery29, Who What Wear, Glimpse, and Beauty Independent.
- The Pretty Picks. PDRN skincare market projected $321M (2025) to $811M (2035). 2026.
- Polydeoxyribonucleotides as emerging therapeutics for skin diseases. Applied Sciences. 2025;15(19):10437. PDRN not FDA-approved; approved in Italy (AIFA, 1994), South Korea (MFDS).
- Squadrito F, et al. Pharmacological activity and clinical use of PDRN. Front Pharmacol. 2017;8:224.
- Akaberi SM, et al. Polydeoxyribonucleotide in skincare and cosmetics: mechanisms, therapeutic applications, and advancements. J Skin Stem Cell. 2025;12(1):e159728.
- Colangelo MT, Galli C, Guizzardi S. Polydeoxyribonucleotide regulation of inflammation. Adv Wound Care. 2020.
- Comparison of polynucleotide and polydeoxyribonucleotide in dermatology: molecular mechanisms and clinical perspectives. PMC. 2025.
- Polynucleotides and polydeoxyribonucleotides in dermatology: a narrative review. JCAS. Jan 2026.
- Lee YJ, et al. Comparison of 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.
- Lampridou S, et al. The effectiveness of polynucleotides in esthetic medicine: a systematic review. J Cosmet Dermatol. 2025. 9 studies, 219 patients, low-moderate quality.
- Rho NK, et al. A survey on the cosmetic use of injectable polynucleotide products among practitioners. J Cosmet Dermatol. 2024;23(6):1234-1242.
- Yoo DB. PDRN/PN and Rejuran: current evidence and clinical perspective. Beverly Hills Facial Plastic Surgery. Sep 2025. Summary of systematic review findings.
- 500 Dalton rule. Standard principle in topical drug delivery; molecules >500 Da have difficulty crossing intact stratum corneum.
- Skin Science Hub. PDRN skincare guide: does salmon DNA work? Pharmacologist review. Dec 2025. Discussion of molecular size barrier, Dr. Dray quote.
- Natural Image Skin Center. Salmon DNA (PDRN) in skincare: trend or science? Discussion of topical vs. injectable evidence gap.
- Philippines FDA Advisory 2022-1001. Public health warning against unregistered Rejuran products.