How PDRN Protects SIRT1, the Master Aging Protein, as Polynucleotides Go Mainstream
Aesthetic trends move fast. The science beneath them moves differently. In May 2025, a study published in PLoS ONE laid out, for the first time in molecular detail, exactly how PDRN (polydeoxyribonucleotide, derived from salmon sperm DNA) works against skin aging. The short version: it keeps SIRT1 alive. SIRT1 is the protein that controls the pace at which your cells age. When it disappears, the clock speeds up. What PDRN does, according to the research, is interrupt the cellular process that breaks SIRT1 down.
This is why Rejuran, the South Korean brand that first turned PDRN into an aesthetic treatment, is now appearing on menus at medical spas in New York, Miami, Los Angeles, and London. Not because of a trend cycle, but because the clinical record has been building for years and the molecular rationale just got a lot clearer.
What a Salmon-Derived Molecule Does Inside Skin
PDRN is a low-molecular-weight linear polynucleotide, ranging from 50 to 1,500 kDa, extracted from the sperm of salmon trout. The purification process removes virtually all protein, leaving a DNA fragment that is structurally similar to human DNA. That similarity is part of why the body integrates it without significant immune response.
Once injected, PDRN binds to adenosine A2A receptors on the cell surface. Think of these as switches: when flipped, they simultaneously quiet inflammation, suppress programmed cell death, and activate tissue regeneration pathways. The result, across multiple clinical studies, is approximately 20 to 30% higher collagen synthesis and a roughly 25% reduction in inflammatory cytokines. Wound healing, skin barrier protection, and hydration retention are the three effects most consistently documented.
The molecule also feeds into nucleotide salvage pathways, providing raw material cells use to repair and replicate DNA. This is one reason PDRN has been used in wound care for decades before it entered aesthetic medicine.
What Happens When SIRT1 Is Protected
SIRT1 is an NAD+-dependent protein that serves as one of the body’s primary regulators of cellular aging. It handles DNA repair, inflammation control, mitochondrial maintenance, and a range of other longevity-associated functions. As skin ages, or when cells are hit with UV radiation or oxidative stress, SIRT1 levels drop. Less SIRT1 means faster collagen breakdown and thinner, less resilient skin.
The 2025 PLoS ONE study by Chen et al. treated keratinocytes (the cells that form the skin’s outer layer) with 800 micrograms per milliliter of PDRN, then exposed them to UVB radiation and hydrogen peroxide. Both are standard models for accelerated skin aging. Cells treated with PDRN showed significantly higher survival rates and substantially restored SIRT1 protein levels compared to untreated cells under the same stress. Senescence markers including p53, p21, and p16 all decreased. In mouse skin exposed to UVB, epidermal thickening reversed toward normal levels after PDRN treatment.
Nuclear Autophagy: The Specific Process PDRN Blocks
The mechanism the study identified involves nuclear autophagy. Autophagy is the cell’s internal recycling process: damaged components get tagged, broken down, and reprocessed. Under normal conditions, it keeps cells clean and functional. Under stress, it can go too far, degrading proteins that are still working correctly.
What the researchers observed was that UV or oxidative stress causes LC3, a key autophagy marker, to accumulate abnormally inside the cell nucleus. When this happens, SIRT1 and another regulatory protein called p62 both get targeted for degradation. PDRN interrupts this specific nuclear autophagy loop, preventing the LC3 accumulation and keeping SIRT1 intact.
This is a more precise story than “antioxidants slow aging.” It specifies which pathway, which proteins, and which sequence of events PDRN interferes with. For researchers and formulators, that clarity opens the door to more targeted applications.
Why Korea Built the Clinical Foundation First
PDRN was initially developed by an Italian pharmaceutical company as a wound healing agent, prescribed for diabetic foot ulcers and post-surgical tissue repair. Korean aesthetic medicine was the first to adapt it for skin rejuvenation. Hanmi Pharmaceutical’s Rejuran brand launched in 2014, introducing the concept of salmon DNA injections into Korean aesthetic practice. Years of accumulated treatment data in Korean clinics provided the safety and efficacy record that made international expansion credible.
Between 2024 and 2026, demand for polynucleotide treatments in the United States accelerated sharply. Medical dermatology clinics and medspas in New York, Miami, Los Angeles, and New Jersey have added Rejuran and comparable PN products to their service menus. In practitioner surveys, 90% of providers describe polynucleotide treatments as effective or highly effective. Social media amplified the trend, but decades of clinical use and a growing body of peer-reviewed research gave it durability.
Standard protocols call for 3 to 4 sessions, spaced four weeks apart. Each session runs 30 to 45 minutes. Numbing cream is applied first, then microinjections are placed into the dermis. Post-treatment redness and swelling typically resolve within a few days. At US medspas, single session pricing generally falls between $300 and $600, varying by market and clinic.
Who Gets the Most From PDRN
PDRN performs best when the goal is repair rather than augmentation. Skin that has accumulated UV damage, is barrier-compromised, chronically dry, or working through acne scarring responds well. So does skin that needs post-procedure recovery support. For patients who want regenerative outcomes without synthetic fillers, it sits in a practical middle ground.
It is not appropriate for everyone. Pregnant patients and anyone with an active autoimmune condition (a category that includes rheumatoid arthritis, lupus, and related diseases) should not receive treatment. Because the source material is salmon-derived, people with significant fish allergies need to discuss this with their practitioner before proceeding. Active skin infections and current anticoagulant use are also standard contraindications.
Polynucleotides vs. Exosomes vs. Skin Boosters
Three categories of regenerative injectable treatments are now competing for the same patient conversations. They work differently.
Polynucleotides (PDRN) activate cellular receptors directly to drive collagen synthesis and tissue repair. They carry the most extensive clinical evidence base of the three. Clinical tracking shows more than 85% of patients achieve moderate or better improvement. The specific strength is repair: damaged barriers, dehydrated skin, wound recovery.
Exosomes are nanoscale vesicles derived from stem cells, carrying growth factors, proteins, and mRNA. They influence a wider range of targets than PDRN, including elastin and hyaluronic acid production. At the 42-day mark in comparative studies, 65% of the exosome group achieved significant improvement on standardized assessment scales. The limitation is regulatory: no FDA-approved aesthetic exosome product currently exists, which creates uncertainty around quality and standardization.
HA skin boosters deliver low-cross-linked hyaluronic acid directly into the dermis for immediate hydration and volume. Results are the most immediate of the three, but the mechanism is closer to “filling” than regenerating. Effects typically last 6 to 12 months before re-treatment is needed.
In practice, the treatments are increasingly complementary rather than purely competitive. PDRN in the recovery phase after laser or resurfacing procedures, exosomes for longer-term anti-aging work, HA boosters for immediate texture and glow. Clinics are building protocols that use all three at different stages.
The label “K-beauty treatment” no longer captures what polynucleotides are. What started as a niche Korean aesthetic procedure is now backed by a molecular mechanism detailed enough to appear in a peer-reviewed journal and referenced by clinics in three continents. The SIRT1 story gives researchers and formulators a specific target. It gives patients a reason beyond trend. The next phase of polynucleotide development will likely move faster for it.
Q. How many PDRN sessions do I need to see results?
Most protocols recommend 3 to 4 sessions spaced four weeks apart. Each session takes 30 to 45 minutes, starting with numbing cream before microinjections into the dermis. Redness and minor swelling clear within a few days, while skin improvements build gradually over several weeks.
Q. PDRN vs. exosomes: what’s the actual difference?
PDRN has decades of clinical history and increases collagen synthesis by roughly 20 to 30% while reducing inflammatory markers by about 25%. Exosomes influence a broader range of targets including elastin and hyaluronic acid production, but no FDA-approved aesthetic exosome products currently exist. PDRN tends to be the stronger choice for damaged, sensitive, or barrier-compromised skin, while exosomes are often favored for post-inflammatory pigmentation and faster visible results.
Q. Is salmon DNA safe if I have a fish allergy?
PDRN is extracted from salmon sperm DNA but is highly purified, leaving almost no protein content. If you have a known fish allergy, you should disclose this to your practitioner before treatment. PDRN is not recommended during pregnancy or for anyone with an active autoimmune condition.