How Rejuran and Polynucleotide (PDRN) Injectables Actually Work: A Complete Guide

1 day ago

5 min read

Polynucleotide injectables, marketed in Korea under names including Rejuran, are purified DNA fragments derived from salmon milt that are injected into the dermis to act on the skin's own repair signalling rather than to add volume.

That mechanism distinction is the whole point, and it is routinely blurred in clinic marketing that groups polynucleotides with hyaluronic acid fillers and skin boosters. They behave differently, take effect on a different timeline, and suit different complaints. This guide explains what PDRN and polynucleotides are understood to do at a cellular level, what the evidence currently supports and does not, how a realistic treatment course is structured, and where the category is over-sold. If pigmentation rather than texture is your main concern, our comparison of tranexamic acid and hydroquinone is the more relevant starting point.

What PDRN and Polynucleotides Actually Are

PDRN stands for polydeoxyribonucleotide: a mixture of DNA fragments, typically in the range of 50 to 1,500 base pairs, extracted and purified from salmon or trout sperm cells. Polynucleotide products are a related preparation with longer chains that also form a soft gel-like matrix in tissue. Salmon DNA is used because its nucleotide sequence is highly conserved and closely comparable to human DNA, which reduces immunogenic risk, and because the source material is abundant and can be purified to a high standard.

Regulatory classification varies by country. In Korea these products are registered and widely used in dermatology and plastic surgery practice; in several other jurisdictions availability is more limited. International patients should not assume the same product is licensed at home.

The Proposed Mechanism, Step by Step

Three actions are described in the literature. First, adenosine A2A receptor activation: nucleotide fragments are thought to stimulate this receptor on fibroblasts and other cells, which is associated with increased growth factor expression and reduced inflammatory signalling. Second, a salvage pathway effect: supplying exogenous nucleotides may reduce the metabolic cost to fibroblasts of synthesising their own, freeing resources for collagen and extracellular matrix production. Third, a physical scaffold effect: longer polynucleotide chains hold water and form a hydrogel-like network that supports cell migration.

The practical consequence is that polynucleotides do not fill a line the way hyaluronic acid does. They are intended to change the quality of the tissue over weeks, which is why the visible result is described as improved elasticity, smoother fine texture and better hydration rather than altered contour.

How This Differs from Hyaluronic Acid Skin Boosters

Injectable hyaluronic acid boosters work primarily by binding water, producing an immediate plumping effect that diminishes as the material is metabolised, typically over several months. The mechanism is physical. Polynucleotide treatment aims at a biological response, so the effect appears more slowly — commonly described from around the third to sixth week — and is claimed to persist after the material itself has resorbed because the tissue change, not the material, is the result.

Clinics frequently combine the two in a single programme. That can be defensible, but it also makes it difficult for a patient to attribute improvement to either component. If you want to know whether polynucleotides work for your skin, a course of polynucleotides alone gives you a clearer answer.

What a Realistic Treatment Course Looks Like

A standard protocol involves 3 to 4 sessions spaced 2 to 4 weeks apart, followed by maintenance at intervals of roughly 4 to 6 months. Injection is by fine needle in a microdroplet pattern, or by cannula in some facial areas, with topical anaesthetic applied 20 to 30 minutes beforehand. Each session typically takes 20 to 40 minutes including numbing time.

Expect visible papules at each injection point for roughly 4 to 24 hours, and bruising in a minority of sessions that can last 3 to 7 days. Patients who plan a single session before an event are likely to be disappointed on both counts: the downtime is front-loaded and the benefit is not.

What the Evidence Supports, and Where It Is Thin

There is a reasonable body of laboratory and animal work supporting the adenosine receptor and fibroblast stimulation mechanisms, and a growing but still limited set of clinical studies reporting improvements in elasticity, hydration and fine wrinkling. Much of the clinical literature involves small sample sizes, short follow-up, and in some cases industry involvement. Comparative trials against hyaluronic acid boosters or energy-based devices are scarce.

A fair summary is that the mechanism is plausible and partly demonstrated, the short-term skin-quality benefit is reported consistently enough to be taken seriously, and claims about long-term structural rejuvenation or scar remodelling are not yet well established. Any clinic presenting polynucleotides as a substitute for surgical lifting or for laser treatment of pigmentation is overstating the case.

The Gap in Most Clinic Explanations: Who Should Not Expect Much

Polynucleotide treatment addresses tissue quality. It does not address volume loss, skin laxity requiring lifting, deep static folds, or pigmentation. Patients whose principal complaint is a sagging jawline or heavy nasolabial folds will see little benefit, and money spent here is better directed elsewhere. Patients with active acne, rosacea flares or any skin infection at the injection site should defer treatment.

Fish protein allergy is a specific contraindication worth raising unprompted, since the source material is salmon-derived. Pregnancy and breastfeeding are generally listed as precautions on the basis of absent safety data rather than known harm. Patients on anticoagulants should expect more bruising.

Risks and Side Effects

The common effects are local and self-limiting: injection papules, erythema, swelling, tenderness and bruising. Less common events include nodule formation, prolonged swelling, and infection at an injection site, which requires prompt clinical review. As with any injectable, sterile technique and an appropriately trained injector matter more than the product brand.

No injectable is risk-free and no product should be described as guaranteed or completely safe. Ask what the clinic's protocol is if a nodule or infection occurs, and confirm that a physician is available for follow-up after you return home.

Frequently Asked Questions

How soon will I see a difference?

Most reports describe initial changes in skin texture and hydration from around week 3 to week 6 after the first session, with fuller effect after completing a 3 to 4 session course. Immediate change after one session is usually swelling, not result.

How long does the effect last?

Commonly cited maintenance intervals are 4 to 6 months, though durability varies with age, skin condition, sun exposure and smoking. Treat any single figure as an average rather than a promise.

Can it be combined with botulinum toxin or lasers?

Combination programmes are common in Korean practice. Sequencing matters — most clinics separate injectable and energy-based sessions by at least one to two weeks to avoid compounding inflammation. Ask for the planned interval in writing.

Is it suitable for acne scarring?

It may improve surrounding skin quality, but it is not a primary treatment for atrophic scars. Subcision, TCA CROSS and fractional resurfacing remain the evidence-supported options for scar architecture.

Is the salmon-derived source a safety concern?

The DNA is purified and sequence-conserved, which is the basis for its low immunogenicity, but patients with known fish allergy should disclose this and are generally advised against treatment.

Next Steps

If your concern is fine texture, dullness and early elasticity loss, a polynucleotide course is a reasonable option to discuss. Ask the clinic which specific product and concentration they use, how many sessions they consider a course, and what they would recommend instead if your main issue turns out to be volume or laxity. Our coordinators can arrange consultations with board-verified dermatology and plastic surgery clinics in Seoul with English, Japanese and Chinese language support.

Sources and Further Reading

Korea Health Industry Development Institute (KHIDI): khidi.or.kr. Korean Society of Plastic and Reconstructive Surgeons (KSPRS): plasticsurgery.or.kr. Peer-reviewed mechanism and outcome literature: PubMed.