You have probably seen PDRN trending across skincare conversations — praised for its role in supporting skin recovery and the appearance of texture, tone, and radiance. But rarely does anyone explain where PDRN actually comes from, how it moves from a fish to a serum, and why the extraction process determines whether the ingredient you're applying does anything meaningful at all.
At Boldpurity, every ingredient in SkinReset™ PDRN Serum is chosen with full traceability in mind. This article covers the complete science of salmon PDRN extraction — from the source species to the purification steps — and why grade and fragment length matter more than simply seeing "PDRN" on an ingredient list.
Salmon PDRN is extracted from the milt (reproductive tissue) of salmon species through a multi-stage pharmaceutical process: cell lysis → DNA isolation → enzymatic hydrolysis into short-chain fragments → extensive purification → standardisation. Only pharmaceutical-grade PDRN with controlled fragment length is considered suitable for high-quality cosmetic formulations.
01 — What Is PDRN?
PDRN stands for Polydeoxyribonucleotide — a chain of deoxyribonucleotide units derived from DNA. In skincare, PDRN refers specifically to short-chain DNA fragments that are associated with adenosine A2A receptor interaction pathways — understood to occur via degradation into nucleotides that participate in adenosine signalling — as reported in dermatological research.
These short fragments are not intact DNA — they do not integrate into human genetic material in topical cosmetic use. They are nucleotide building-block sequences that skin tissue is understood to recognise and interact with through specific receptor pathways. The result, documented in peer-reviewed literature, is an association with improved appearance of skin texture, tone, and overall radiance over time.
The origin of the PDRN matters enormously — because not all PDRN is produced the same way, and not all PDRN on an ingredient list reflects the same purity, fragment length, or biological compatibility.
The INCI name for cosmetic PDRN is Sodium DNA. When you see Sodium DNA on a Boldpurity ingredient list, that is the standardised cosmetic labelling for pharmaceutical-grade salmon PDRN — the same material discussed throughout this article.
02 — Why Salmon? The Species Rationale
The use of salmon as a PDRN source is not arbitrary. Salmon milt — the sperm-producing tissue of male salmon — is one of the most DNA-dense biological materials available. Two species are most commonly used in pharmaceutical and cosmetic PDRN production:
There are three key scientific reasons salmon is preferred over other DNA sources:
1. DNA density. Salmon milt contains exceptionally high concentrations of DNA relative to tissue weight. This supports efficient extraction and consistent concentration standardisation in the final ingredient — a manufacturing advantage that contributes to supply reliability.
2. Adenine-thymine (AT) richness. Salmon DNA is particularly rich in adenine-thymine base pairs. PDRN-derived nucleotides are associated with adenosine A2A receptor interaction pathways in dermatological research — this is the biological basis considered when sourcing PDRN for skin applications, though the precise role of AT base composition within that pathway is an area of ongoing research.
3. Common nucleotide structure. Salmon DNA shares the same fundamental nucleotide structure common to all DNA — the same building blocks of deoxyribose sugar, phosphate groups, and nitrogenous bases. This shared biochemical foundation is considered relevant to the skin compatibility of PDRN-derived fragments.
03 — The Extraction Process: Step by Step
From fish milt to cosmetic-grade PDRN, the extraction involves six distinct stages. Each step has a specific purpose — and cutting corners at any stage directly affects the safety and performance profile of the final ingredient.
Salmon milt (testes tissue) is collected from male fish during the processing stage of the fish food industry. The milt is separated, weighed, and transferred under temperature-controlled conditions to prevent DNA degradation. Speed and cold-chain management at this stage are critical — DNA begins to degrade rapidly at ambient temperatures.
The milt tissue is mechanically disrupted — homogenised — and treated with detergents or enzymatic agents to rupture the sperm cell membranes. This releases the DNA content from within the cells into solution, along with proteins, lipids, and other cellular debris that must be removed in subsequent steps.
The crude DNA is precipitated from the lysate using cold ethanol or isopropanol — standard nucleic acid precipitation chemistry. Centrifugation separates the DNA pellet from the supernatant (which contains unwanted lipids, small proteins, and soluble debris). The DNA pellet is then washed and redissolved in a controlled buffer solution.
This is the defining step. The full-length salmon DNA — which is far too large to be meaningfully available in skin — is cleaved into short-chain polynucleotide fragments using controlled enzymatic hydrolysis. Specific nuclease enzymes cut the DNA at precise points, producing fragments of defined base-pair length ranges. The conditions of this step — enzyme type, temperature, duration, pH — directly determine the fragment length distribution of the final PDRN. This is where pharmaceutical manufacturers differentiate themselves from lower-grade producers.
The fragmented PDRN solution undergoes a series of purification steps — dialysis to remove small molecule contaminants, ultrafiltration to remove residual proteins and achieve target molecular weight distribution, and activated-carbon treatment or ion-exchange chromatography to remove endotoxins. Endotoxin removal is non-negotiable for any ingredient intended for skin application, as endotoxin contamination is associated with cutaneous irritation responses.
The purified PDRN is sterile-filtered, concentration-standardised (typically expressed in mg/mL), and tested against a defined specification — including purity grade, fragment length distribution, endotoxin levels, pH, and sterility. Only PDRN that passes every parameter is released for cosmetic or pharmaceutical ingredient use. This batch-release model is what separates pharmaceutical-grade PDRN from ungraded alternatives.
04 — Why Fragment Length Determines Activity
Fragment length is one of the most underappreciated variables in PDRN quality — and it is rarely disclosed on product labels or brand marketing pages.
Long-chain DNA molecules — those with thousands of base pairs — are far too large to interact meaningfully with the upper layers of skin. They sit on the surface, providing at best a mild humectant-like film. Short-chain fragments — ranging from approximately 50 to 2,000 base pairs — are considered more relevant to adenosine pathway participation in dermatological research, as they are understood to degrade into nucleotides that enter adenosine signalling pathways rather than binding directly to receptors as intact molecules.
The enzymatic hydrolysis step (Step 4 above) is where fragment length is set. Manufacturers who control this step with precision produce PDRN with a defined, reproducible fragment length distribution. Those who do not — or who use lower-grade hydrolysis approaches — may produce PDRN that is structurally inconsistent batch to batch.
The relationship between PDRN fragment length and skin availability is documented in peer-reviewed dermatological and pharmacological literature. Fragment length is considered an important factor influencing availability and interaction in upper skin layers, though optimal ranges vary across studies and evidence remains model-dependent. Research published in journals including Frontiers in Pharmacology and Applied Sciences has characterised short-chain fractions as more relevant to adenosine pathway participation than long-chain intact DNA. Evidence classification: Moderate — documented in laboratory and in vivo research; mechanism is indirect via nucleotide degradation pathways.
05 — Pharmaceutical-Grade Purity Standards
The phrase "pharmaceutical-grade" is specific — it is not a marketing superlative. It refers to PDRN that has been manufactured under GMP (Good Manufacturing Practice) conditions and tested against a defined quality specification before release. Key parameters include:
Non-pharmaceutical sources of PDRN — produced without GMP controls or without rigorous fragment length management — cannot reliably meet these parameters. The concern is not simply lower efficacy; pharmaceutical-grade status ensures safety, consistency, and controlled composition — not automatically superior skin performance. However, the absence of endotoxin and allergen controls carries safety and tolerability risks from residual contaminants that may provoke immune or irritation responses. This is why sourcing transparency matters — and why Boldpurity's formulation process specifies pharmaceutical-grade Sodium DNA as the input material for SkinReset™.
06 — Sustainability and Responsible Sourcing
A common question about salmon-derived ingredients is whether their use raises sustainability concerns. The answer, in the context of PDRN, is more nuanced than a simple yes or no.
Salmon milt is a byproduct of the commercial fish food processing industry. In conventional fish processing, milt is separated from the flesh and would otherwise be discarded as processing waste. PDRN manufacturers that source milt from responsible processing facilities are repurposing a byproduct stream — not driving additional fish harvesting for the ingredient alone.
This does not mean all PDRN sourcing is equivalent. Responsible procurement requires traceability back to the source facility, confirmation that the supply is a genuine byproduct stream, and alignment with relevant fisheries standards where applicable. As PDRN demand grows alongside global skincare interest, sourcing transparency at the ingredient supplier level becomes an increasingly important factor for brands and consumers alike.
The same byproduct principle applies to other well-established cosmetic ingredients — collagen sourced from hide processing, hyaluronic acid from poultry comb processing, and marine-derived lipids from omega-3 oil production. The cosmetic industry has a long precedent of converting food-industry byproduct streams into high-value cosmetic actives.
07 — What This Means for Your Skin
Understanding the extraction process reframes what you are looking for when choosing a PDRN serum. The question is not just whether PDRN appears on an ingredient list — it is whether the PDRN used was extracted and purified to a standard that makes it meaningfully available in the upper skin layers and free from the contaminants that could undermine its tolerance profile.
Skin is a barrier system. Its outermost layers — the stratum corneum — are composed of densely packed corneocytes and an extracellular lipid matrix that regulates what can and cannot pass through. Ingredient availability in the upper skin layers depends on molecular size, charge, and the delivery strategy used by the formulation.
Short-chain PDRN fragments are understood to interact with the stratum corneum environment more readily than long-chain intact DNA. PDRN is understood to act via degradation into nucleotides that participate in adenosine receptor pathways — rather than intact fragment binding directly to receptors. When supported by a delivery system — such as the encapsulation approach used in SkinReset™ — PDRN's opportunity to be available in the upper skin layers is supported further. This layering of extraction quality and delivery strategy is what separates a functional PDRN formulation from a label-only inclusion.
08 — How to Choose a PDRN Serum
Given everything covered above, here is a practical checklist for evaluating any PDRN serum on the market:
- Pharmaceutical-grade Sodium DNA — the INCI name that indicates properly processed PDRN, not crude DNA extract
- Encapsulation or delivery technology — confirms the formulator has addressed the delivery challenge, not just the ingredient inclusion
- cGMP certified manufacturer — confirms manufacturing conditions meet quality and safety standards
- Transparent ingredient list — a brand confident in its formulation will not hide what's inside
- No unqualified claims — phrases like "DNA repair" or "heals the skin" are regulatory red flags, not quality indicators
SkinReset™ PDRN Serum by Boldpurity is formulated with pharmaceutical-grade Sodium DNA (PDRN) alongside 5% Niacinamide, White Lily Extract, and Undecylenoyl Phenylalanine (Sepiwhite™) — delivered in a patented-pending Dual Encapsulation system. Boldpurity is cGMP certified and founded by an IFSCC-recognised cosmetic scientist. The formulation reflects every criterion in the checklist above.
Pharmaceutical-grade Sodium DNA · 5% Niacinamide · Sepiwhite™ · Dual Encapsulation Delivery Technology · cGMP Certified
Shop SkinReset™ Serum →Frequently Asked Questions
Salmon PDRN is derived from milt — the reproductive tissue of male salmon. The DNA within the milt cells is extracted, fragmented into short-chain polynucleotides through enzymatic hydrolysis, and purified to pharmaceutical-grade standards before use as a cosmetic active ingredient.
Pharmaceutical-grade PDRN is well-documented in dermatological research for its tolerability on skin. The extensive purification process — endotoxin removal, protein clearance, sterile filtration — is specifically designed to produce an ingredient that is safe for topical application. Ungraded or poorly purified PDRN, however, carries a higher risk of irritation from residual contaminants.
Salmon milt offers a combination of high DNA density — which supports efficient extraction and production consistency — and high adenine-thymine base-pair content. PDRN-derived nucleotides are associated with adenosine A2A receptor interaction pathways in dermatological research. Salmon milt also shares the same fundamental nucleotide structure common to all DNA, which is considered relevant to skin compatibility.
Fragment length refers to the number of base pairs in each PDRN molecule after the hydrolysis step. Fragment length is considered an important factor influencing availability and interaction in upper skin layers, though optimal ranges vary across studies. PDRN is understood to act via degradation into nucleotides that participate in adenosine receptor pathways, rather than through direct receptor binding as intact fragments. Pharmaceutical manufacturers control fragment length during enzymatic hydrolysis to produce PDRN with a defined, reproducible composition.
PDRN is extracted from salmon milt, which is a byproduct of commercial fish food processing. In responsible supply chains, the milt would otherwise be discarded as processing waste. Repurposing it as a cosmetic active ingredient supports a circular approach to ingredient sourcing. Traceability back to the processing facility remains important for confirming byproduct status.
Pharmaceutical-grade PDRN has been manufactured under GMP (Good Manufacturing Practice) conditions and tested against a defined quality specification covering fragment length, endotoxin levels, protein residues, concentration, and sterility. Every batch is released only if it passes all parameters. This grade of PDRN is what is used in the SkinReset™ PDRN Serum formulation.
PDRN (Sodium DNA) is a fragmented DNA molecule — a chain of deoxyribonucleotides associated with adenosine receptor pathways. EGF (sh-Oligopeptide-1) is a protein signalling molecule that interacts with growth factor receptors. Hyaluronic acid is a polysaccharide humectant that functions through moisture-binding capacity. Each operates via a distinct mechanism, which is why they serve complementary — not interchangeable — roles in a skincare formulation.
Formulated with short-chain Sodium DNA delivered via Dual Encapsulation Technology. cGMP certified. Patent pending.
- Bitto A, et al. "Pharmacological Activity and Clinical Use of PDRN." Frontiers in Pharmacology, 2017. PMC5405115
- Jeong HS, et al. "Polynucleotides in Aesthetic Medicine." International Journal of Molecular Sciences, 25(15), 2024. MDPI
- Chung YH, et al. "Polydeoxyribonucleotide: A Promising Skin Anti-Aging Agent." Journal of Cosmetic Dermatology, 2022. ScienceDirect
- Guida S, et al. "Polydeoxyribonucleotides as Emerging Therapeutics." Applied Sciences (MDPI), 15(19), 2025. MDPI
- Park JH, et al. "Versatile and Marvelous Potentials of Polydeoxyribonucleotide." PMC, 2025. PMC11994882
- Akaberi SM, et al. "Polydeoxyribonucleotide in Skincare and Cosmetics." Journal of Skin Stem Cell, 12(1), 2025. Brieflands
- Bos JD, Meinardi MM. "The 500 Dalton rule for the skin penetration of chemical compounds." Experimental Dermatology, 2000. PubMed
