PDRN

What it is

PDRN (polydeoxyribonucleotide) is a mixture of low molecular weight DNA fragments (typically 50–1,500 base pairs) extracted from salmon or trout sperm cells and purified through processes that remove protein and other contaminants. The DNA fragments are proposed to act as signaling molecules rather than as building blocks of new DNA.

PDRN was developed in Italy by Mastelli s.r.l. starting in the 1950s and has been used in Italy and several other countries for decades. It received approval in Italy and South Korea for various wound healing and tissue regeneration indications. Over 100 clinical studies have been published, primarily from Italian and Korean research groups. PDRN is not FDA-approved for any use in the United States.

The salmon/trout source was chosen in part because of the structural similarity of these species’ DNA to human DNA, which has been proposed to influence the activity of the resulting fragments. The molecular weight range of the fragment mixture is tightly controlled, as reported biological activity is fragment-size-dependent.

Mechanism of action

Proposed mechanisms come from laboratory and animal research, and center on adenosine A2A receptor activation, with secondary contributions from nucleotide salvage:

• Adenosine A2A receptor agonism: the DNA fragments are thought to be partially broken down in tissue to release adenosine and adenine derivatives, which bind A2A receptors expressed on endothelial cells, fibroblasts, and immune cells. In laboratory and animal studies, A2A activation has been reported to:
  • Increase VEGF expression and angiogenesis
  • Increase fibroblast proliferation and collagen synthesis
  • Reduce pro-inflammatory cytokine production
  • Increase blood flow to injured tissue
• Nucleotide salvage pathway: it has been hypothesized that nucleotides released from PDRN may supply raw materials for DNA repair and synthesis in cells with high turnover.
• Inflammatory cell effects: some laboratory studies suggest direct effects on inflammatory cell function independent of the A2A pathway.

Research findings

Most published clinical research on PDRN comes from studies conducted outside the US; these findings have not been evaluated by the FDA.

Diabetic foot ulcers: randomized trials, mainly from Italy and Korea, and a 2019 meta-analysis have been published; benefit in people has not been established in FDA-reviewed trials.

Osteoarthritis: intra-articular PDRN has been studied in knee osteoarthritis; benefit in people has not been established.

Wound healing (non-diabetic): studies in burn injuries, post-surgical wounds, and chronic venous ulcers have been published; benefit in people has not been established.

Aesthetic and dermatological use: PDRN is used in cosmetic medicine in Korea in so-called “salmon DNA” treatments; published evidence for these uses is limited.

Tendon and soft-tissue injury: small early studies have examined PDRN in chronic tendinopathy, with limited and preliminary results.

Well-controlled trials establishing the effectiveness and safety of PDRN in US populations are lacking.

Side effects and contraindications

Human safety of PDRN has not been established in well-controlled US trials, and long-term effects are unknown. Products sold outside regulated channels may vary in purity, dose, and sterility.

Theoretical concerns have been raised for:

• Salmon or fish allergy: while purification removes most protein, trace amounts may remain. People with documented salmon, trout, or significant fish allergy should not receive PDRN.
• Active malignancy: the regenerative and angiogenic effects reported in research raise theoretical concerns in people with active or recent cancer.
• Pregnancy and breastfeeding: avoided in absence of safety data.
• Severe immunodeficiency: a theoretical concern, given reported immune-modulating effects.

What we don’t yet know

Most of the clinical evidence base comes from Italian and Korean research groups; Western RCT replication is limited. Effectiveness and safety for specific conditions have not been established in US trials. How PDRN compares with other regenerative interventions (PRP, prolotherapy, biologics) has not been established in head-to-head studies. The exact contributions of different fragment-size populations within PDRN preparations are still being researched.