Key Takeaways
- PDRN is purified DNA — usually from salmon — used in some markets as a skin injection
- It targets skin quality rather than volume — not comparable to filler
- Protocols typically describe 3–4 sessions, 2–4 weeks apart, with changes around week 4–8
- Regulatory status for the injectable form varies by country
You probably saw the phrase before you saw any of the science. Salmon DNA. It shows up in a video caption, or on a clinic menu in Seoul, or in a group chat where someone's cousin swears by it. The name does most of the work, and not always in a helpful way — it sounds either miraculous or slightly alarming, depending on the day you hear it.
The plain explanation is shorter and much less dramatic than the internet makes it. This is the version that fits in a coffee break.
Salmon DNA, minus the marketing
PDRN stands for polydeoxyribonucleotide. It is a mixture of DNA fragments, purified and sterilized, and according to a narrative review in the Journal of Cutaneous and Aesthetic Surgery, it is mostly sourced from the reproductive cells of salmon and trout — species like Oncorhynchus keta and Oncorhynchus mykiss.
Size turns out to matter more than the source. That same review specifies a working range of 50 to 1,500 kilodaltons, and notes that fragments outside it do not bind to the receptor PDRN is meant to act on. So a product can list salmon-derived DNA and still not behave like PDRN — worth knowing if you ever compare two labels that read almost identically.
Rejuran is the brand name most widely associated with PDRN in Korea. It is one PDRN product, not a distinct category of treatment.
A timeline, and what the research does and doesn't show
Protocols vary by clinic, but the JCAS review describes a fairly consistent pattern: injections every two to four weeks, across three to four sessions. Reported changes typically appear somewhere between week four and week eight, and continue developing over three to six months.
That slow curve is the part people underestimate. Booking a single session two weeks before a wedding will most likely disappoint — and not because anything went wrong.
You are allowed to just ask questions
Five minutes will not make anyone an expert, and it is not supposed to. What it should do is let you sit in a consultation and follow the conversation, rather than nodding along at words you are quietly guessing at.
If PDRN sounds like it might suit what you are after, the useful next step is a conversation with a licensed provider who can look at your skin and tell you honestly whether it does. Ask what is in the syringe. Ask how many sessions they would suggest, and why that number. A clinic worth your time will not mind being asked.
Sources ▶ 1) Journal of Cutaneous and Aesthetic Surgery — "Polynucleotides and polydeoxyribonucleotides in dermatology: A narrative review"; 2) Park et al. 2025, "Polydeoxyribonucleotides as Emerging Therapeutics for Skin Diseases," Applied Sciences 15(19):10437. Timing and protocol figures reflect the literature and vary in practice.
