Rejuran: Healing Skin from Within

Polynucleotides are chains of nucleotides — the building blocks of DNA — purified from salmon DNA. Salmon is used because its DNA structure is highly compatible with human tissue and can be purified to a high standard.

Once injected into the skin, polynucleotides act as a biological scaffold and signal. They hold water, support fibroblast activity (the cells that produce collagen and elastin), and appear to have an anti-inflammatory effect. The intent is to improve the skin's own function rather than to impose a shape on it.

One point of transparency: much of the published research on polynucleotides comes from South Korea, where the technology originated, and some of it is industry-sponsored. The clinical experience is substantial and patient satisfaction is generally high, but the independent long-term evidence base is smaller than for older treatments such as botulinum toxin.

The two formulations differ in concentration and viscosity because the areas they treat are structurally different.

An important clarification about dark circles, because this is where expectations most often go wrong. Under-eye darkness has several causes: pigmentation, thin skin showing underlying vasculature, and shadowing cast by a hollow. Rejuran Eye can improve the quality and thickness of thin skin, which helps where vasculature is showing through. It does not fill a hollow — that requires filler — and it does not treat true pigmentation. If nobody has told you which of these you actually have, the treatment plan is a guess.

These three are frequently compared and do quite different things.

• Rejuran (polynucleotide) — supports repair and improves skin quality over a course of sessions. Best for texture, elasticity and resilience.
• Profhilo (bio-remodelling hyaluronic acid) — delivers intense hydration and improves laxity through slow HA release. Best for crepey, dehydrated skin. Usually two initial sessions four weeks apart.
• Dermal filler — adds structural volume and contour. Best for hollowing, projection and definition. It does not improve skin quality.

A standard initial course is three to four sessions spaced two to four weeks apart, followed by maintenance every six to twelve months. A single session will not deliver the result the treatment is capable of.

The treatment involves many small injections, so topical numbing is applied first, usually for 20–30 minutes. The injections themselves take around 15–20 minutes.

Expect small raised bumps immediately afterwards where the product has been deposited. These typically settle within 24–48 hours, though under the eyes they can take slightly longer. Bruising is possible, particularly in the periorbital area. This is worth planning around — do not book a course two days before an event.

Results build gradually over six to twelve weeks as the skin responds. Most people notice improved smoothness and a change in how their skin feels before they see a visible difference in photographs.

Rejuran suits people whose concern is skin quality rather than volume: dullness, rough texture, early fine lines, loss of elasticity, or thin crepey under-eye skin. It is a reasonable option for people who want a regenerative rather than a volumising approach, and it can be useful in people who are not good candidates for filler.

It is not appropriate for anyone with a fish or seafood allergy, given the salmon-derived source. It is avoided in pregnancy and breastfeeding, during active skin infection in the treatment area, and in people with certain autoimmune conditions — all of which should be raised at consultation.

It will not lift sagging skin, replace lost volume, or remove deep static lines. Anyone promising those outcomes from Rejuran is describing a different treatment.