Polynucleotides (PDRN) & GHK-Cu. SkinPen peptide add-ons.
PDRN polynucleotides and GHK-Cu copper peptide as SkinPen add-ons — salmon-DNA-derived tissue regeneration, where each fits, evidence base.
Polynucleotides — PDRN, for polydeoxyribonucleotide — are purified DNA fragments derived from salmon, used to stimulate tissue regeneration. As a SkinPen add-on, the solution is applied into open micro-needling channels, where it supports fibroblast activity and skin repair. This page also covers GHK-Cu, a copper peptide with a complementary wound-healing mechanism. Both are emerging treatments in the U.S.; PDRN carries a longer clinical track record in Korea and Europe.
PDRN, from salmon DNA to skin.
PDRN is a standardized preparation of short DNA fragments purified from salmon — chosen because salmon DNA is structurally compatible with human tissue and can be processed to pharmaceutical grade, with the proteins that drive fish allergy removed. The fragments are biologically active rather than genetic in function: they don't alter your DNA; they feed and signal the cells that repair skin.
Two mechanisms are described in the literature. PDRN activates the adenosine A2A receptor — a signaling pathway involved in tissue repair and inflammation control — and its breakdown products supply the salvage pathway, giving dividing cells ready-made building blocks for DNA synthesis. The practical readout in published studies: increased fibroblast activity, more collagen, faster wound healing.
PDRN is not a new molecule. Injectable PDRN has been a registered pharmaceutical in Italy since the 1990s for wound and tissue repair, and polynucleotide skin treatments became mainstream in South Korean dermatology over the past decade. That history is evidence of clinical familiarity, not FDA endorsement — in the United States, polynucleotides are an emerging category, and we describe them accordingly.
GHK-Cu, the copper tripeptide.
GHK-Cu is a three-amino-acid peptide — glycyl-histidyl-lysine — bound to a copper ion. It occurs naturally in human plasma, and its concentration declines steeply with age, which is part of why it has drawn research interest as a skin-repair signal.
Its documented effects sit alongside PDRN's rather than on top of them: GHK-Cu supports collagen and elastin synthesis, carries anti-inflammatory and antioxidant signaling, and copper itself is a required cofactor for lysyl oxidase, the enzyme that cross-links new collagen into stable fibers. We typically layer GHK-Cu with PDRN or another add-on for reactive, red, or slow-recovering skin rather than running it alone.
The hedge, stated plainly: much of the GHK-Cu literature is laboratory and small-cohort work. We treat it as a supporting actor with a plausible, well-described mechanism — not a headline treatment.
How they get into the skin.
At our practice, both ride the SkinPen. The device creates micro-channels at a controlled depth; the PDRN solution or GHK-Cu serum is applied during and immediately after the pass, while the channels are open, and a final layer is left on the skin. In Korea and Europe, PDRN is also delivered by micro-injection as a skin booster — often under brand names patients have encountered, such as Rejuran. Injectable polynucleotides aren't FDA-approved, so the channel-topical route is how we run it here.
The protocol matches the standard SkinPen series: three sessions, four to six weeks apart, with one to three days of redness after each.
Where PDRN and GHK-Cu earn their place.
| Under-eye | Crepey, thin under-eye skin is the indication PDRN is best known for in Korean practice — tissue too delicate for aggressive lasers, treated at conservative needling depth. |
|---|---|
| Neck | Horizontal lines and thinning skin on the neck respond slowly to almost everything; PDRN's fibroblast stimulus is one of the more defensible options short of energy devices. |
| Hands | Crepe and thinning on the backs of the hands — a small treatment area where skin-quality work reads quickly. |
| Post-acne texture | Atrophic scarring and textural irregularity, where the published Korean scar data lines up most directly with the indication. |
Four add-ons, compared.
All four ride the same SkinPen channels. Evidence maturity is the honest axis — and the reason the consultation exists.
| PDRN | PRP | Exosomes | GHK-Cu | |
|---|---|---|---|---|
| Mechanism | Adenosine A2A signaling plus salvage-pathway substrate for repair | Platelet growth-factor release in the channels | Vesicle-delivered growth factors and microRNA | Copper-dependent collagen cross-linking; anti-inflammatory signaling |
| Source | Purified salmon-DNA fragments | Your own blood, same-day draw | Lab-cultured, cell-derived vesicles | Synthesized peptide bound to copper |
| Evidence maturity | Established in Korea and the EU; emerging in the U.S. | The most established of the four | The newest; strongest data is preclinical | Long-studied molecule; mostly lab and small-cohort data |
| Best for | Under-eye, neck, hands, post-acne texture, mature skin | Routine skin-quality and texture work | Diffuse photoaging; post-procedure recovery | Reactive or red skin, layered with another add-on |
Performed by Orr Swissa-Amran, PA-C, board-certified Physician Associate, internationally trained in hair restoration and aesthetic medicine.
Questions we get.
How much do polynucleotide treatments cost?
Within the broader Los Angeles regenerative-microneedling range of $600 – $1,500 per session — above PRP, below exosomes. GHK-Cu is typically a modest layered addition to a session rather than a standalone price. Our pricing is set at consultation, with series totals in writing.
How strong is the evidence?
Stronger than the newest add-ons, younger than PRP's. Injectable PDRN has decades of pharmaceutical use in Italy and a deep Korean dermatology literature; U.S. adoption is recent, and the polynucleotide products used here aren't FDA-approved drugs. GHK-Cu's data is mostly laboratory and small-cohort. We'd rather state that plainly than borrow confidence the literature doesn't yet have.
PDRN or exosomes — how do I choose?
By indication and by your comfort with evidence maturity. PDRN has the longer human track record and the better case for under-eye, neck, and post-acne texture; exosomes carry a broader signaling load with a younger evidence base. The table above is the sketch; the consultation is the decision.
How many sessions will I need?
Three, four to six weeks apart — the standard SkinPen cadence. Under-eye and neck work sometimes extends to four sessions because the tissue is thin and we deliberately treat conservatively per visit.
Is salmon DNA safe — what about fish allergies?
PDRN is purified specifically to remove the proteins that drive fish allergy, and reported reactions are rare. We still flag any fish allergy at consultation and can patch-test or choose a different add-on — there are four on the menu for a reason.
Continue.
Microneedling layered with growth factors, exosomes, PDRN or copper peptide. What each add-on does, what it costs you in downtime.
Blood-derived growth factors microneedled into skin. What it is, what it isn't, and how it differs from the broader regenerative menu.
Microneedling with exosomes — extracellular vesicles applied into SkinPen channels. What the evidence shows, how it compares with PRP.
Paramedical tattooing that blends a mature scar into the surrounding skin tone — the same technique the Ruth Swissa studio is known for nationally, now performed inside the Med Spa's clinical envelope.