What Does Rejuran Actually Do?
Understanding Skin Quality, Polynucleotides, and Modern Skin Rejuvenation
I introduced Rejuran into my practice in 2024, after it received TGA approval for use in Australia. Up until that point I’d felt there was a genuine gap in cosmetic medicine when it came to treating the under-eye area safely.
Patients often come to consultation with the same concern:
“I look tired all the time.”
The challenge is that the under-eye region is delicate, anatomically complex, and not especially forgiving. Many traditional volumising treatments carry risks in this area, including persistent swelling, unnatural texture, or, in rare cases, vascular occlusion leading to blindness. Personally, I had never been entirely comfortable using conventional biostimulatory products there.
So when Rejuran arrived, I was interested immediately.
Here was a product with no hyaluronic acid, a very different biological mechanism, and a growing body of discussion around skin quality and tissue repair. Add in the internet fascination with the so-called “salmon sperm facial,” and patients suddenly became very curious about it as well.
Since introducing it into my practice, I’ve now performed hundreds of treatments. The results have been consistently encouraging, particularly around the under-eye area and in patients wanting subtle, natural-looking rejuvenation. Complications have been minimal, mostly mild bruising, and patient satisfaction has been high. But despite all the marketing online, one question still comes up repeatedly:
“What does Rejuran actually do?”
The answer is more nuanced and more interesting than social media often suggests.
The Shift Toward Skin Quality
One of the biggest changes happening in aesthetic medicine right now is the move away from dramatic alteration and toward skin quality. Patients are becoming less interested in looking “done,” and more interested in looking healthier, fresher, and more rested.
For years, cosmetic medicine largely revolved around volume replacement and wrinkle reduction. Those treatments still absolutely have a role, but increasingly, patients recognise that healthy-looking skin itself contributes enormously to how youthful someone appears.
Good skin reflects light differently.
It moves differently.
It recovers differently.
It simply looks healthier.
That broader concept of texture, hydration, elasticity, resilience, and overall skin integrity is what practitioners now refer to as skin quality. This is where treatments like Rejuran enter the conversation.
What Is Rejuran?
Rejuran is based on polynucleotides, commonly abbreviated to PN. These polynucleotides are derived from highly purified salmon DNA - specifically salmon sperm DNA.
Yes, patients usually pause at that point during consultation as well.
The reason salmon DNA is used is because it has a high degree of compatibility with human DNA structure, while maintaining a very low likelihood of allergic reaction after purification.
Importantly, Rejuran is not like traditional filler. It is not designed to volumise the face dramatically or reshape facial structure. Instead, it sits within a broader category of treatments focused on supporting skin quality and tissue repair biology. That distinction is important, because cosmetic medicine has become saturated with exaggerated claims. If we’re going to discuss “evidence-based” treatments properly, we need to separate marketing language from actual clinical evidence.
So let’s look at some of that evidence.
What Does the Research Actually Show?
One of the more clinically relevant studies involving polynucleotides was published in the Journal of Korean Medical Science in 2014, investigating the use of polydeoxyribonucleotide (PDRN) in pressure ulcer healing. Now, pressure ulcers are obviously very different from cosmetic concerns, but biologically, wound healing and tissue repair rely on many of the same underlying mechanisms that influence skin recovery and skin quality. That’s what makes the paper relevant. The study was a randomised controlled pilot trial involving patients with chronic pressure ulcers wounds that are notoriously difficult to heal because of impaired blood supply, inflammation, and compromised tissue repair. Patients receiving PDRN injections demonstrated measurable improvements in wound healing progression and wound size reduction compared with standard care alone, without major adverse effects reported during the study period. What becomes particularly interesting is how the authors proposed the treatment may be working. The paper discussed several biological pathways, including activation of the adenosine A2A receptor pathway an area associated with:
tissue repair
angiogenesis
cellular proliferation
modulation of inflammatory injury
In simple terms, the treatment appeared to influence the biological environment involved in healing.
Another important theme was vascular support. Chronic wounds often struggle because of impaired perfusion and poor oxygen delivery, so improved vascular signalling may play a role in supporting tissue recovery.
None of this proves that Rejuran “reverses ageing”. And it certainly does not prove miraculous skin regeneration. But it does provide legitimate clinical evidence that polynucleotides have biological activity relevant to tissue repair. That’s a far more scientifically defensible statement.
Fibroblasts, Collagen, and the Extracellular Matrix
A later review paper published in Pharmaceuticals in 2021 expanded further on these mechanisms. This review brought together evidence relating to:
fibroblast activity
extracellular matrix organisation
angiogenesis
inflammatory signalling
tissue remodelling
wound healing biology
This matters because fibroblasts are central to skin structure and repair. They play key roles in collagen production, connective tissue maintenance, and dermal support. Meanwhile, the extracellular matrix (often abbreviated to ECM) acts as the structural environment surrounding skin cells, helping regulate hydration, repair signalling, and tissue organisation. If you’ve read some of my other articles on skin biostimulation, you’ll know I place a huge emphasis on understanding the extracellular matrix properly. Modern cosmetic medicine sometimes becomes overly focused on “stimulating collagen” without enough discussion around the quality of tissue being produced or the inflammatory pathways involved. That’s one reason I remain cautious about repeated aggressive energy-based treatments that rely on controlled tissue injury. These stimulate collagen production via repair pathways, after deliberately causing a localised injury.
The important point here is balance. The evidence suggests polynucleotides may support aspects of tissue repair biology and skin quality. What the evidence does not show is that:
PN reverses ageing
PN completely regenerates skin
PN guarantees collagen production
PN repairs DNA damage cosmetically
PN produces predictable results in every patient
Any practitioner claiming certainty beyond that is moving well ahead of the science.
Why Skin Changes With Age
Ageing skin undergoes multiple structural changes simultaneously. Collagen production gradually declines. Elastin integrity changes. Fibroblast activity slows. The ECM becomes less organised. Hydration patterns shift. Recovery capacity decreases. Over time, this contributes to:
thinner skin
reduced elasticity
fine lines
slower healing
altered texture
increased fragility
Importantly, many patients experiencing these changes are otherwise healthy, well-rested, and taking good care of themselves. That’s why the phrase “I just look tired” comes up so often during consultation. In many cases, patients are not looking for dramatic transformation. They simply want healthier-looking skin and a fresher overall appearance without looking obviously treated. Personally, I think this is where modern aesthetic medicine works best.
Where Rejuran Fits Into Modern Cosmetic Medicine
Based on the current evidence, I think it is reasonable to say that polynucleotides have been studied in wound healing and tissue repair contexts, with biological mechanisms that may also be relevant to skin quality treatments. That does not mean they are magical. And it does not mean every patient is suitable. But within carefully selected treatment plans, Rejuran can be a very useful option particularly for patients wanting subtle, natural-looking rejuvenation and improved skin quality rather than obvious volume change.
As always, appropriate assessment matters.
At Cosmenon, consultations focus heavily on anatomy, skin quality, treatment sequencing, risk assessment, and long-term planning. Treatments are individualised following medical assessment and discussion of suitability, alternatives, and realistic expectations. Ultimately, good cosmetic medicine should still look like you - just healthier, fresher, and better rested.
FAQs About Rejuran
What does Rejuran do for the skin?
Rejuran is commonly discussed as a skin quality-focused treatment involving polynucleotides (PN). It is generally incorporated into treatment plans centred on hydration, texture, and overall skin quality support.
Is Rejuran a filler?
Rejuran is generally considered separately from traditional volumising dermal fillers. It is more commonly associated with skin quality-focused treatment approaches.
What is PN?
PN stands for polynucleotide, a category of DNA-derived fragments studied in tissue repair and regenerative medicine contexts.
Does Rejuran change facial shape?
Rejuran is not typically discussed as a treatment designed to dramatically alter facial shape or structure.
Why are skin quality treatments becoming more popular?
Many patients are increasingly seeking subtle, natural-looking approaches focused on healthier-looking skin rather than obvious cosmetic change.
Can the under-eye area be assessed during consultation?
Yes. The under-eye area is commonly discussed during cosmetic consultation because multiple anatomical and skin-quality factors can contribute to a tired appearance.
Is consultation important before cosmetic treatment?
Yes. Appropriate consultation allows assessment of anatomy, suitability, risks, alternatives, and realistic treatment planning. At Cosmenon, consultations focus on assessment, anatomy, and longterm skin quality planning. Treatment recommendations are individualised following medical assessment and discussion of suitability, alternatives, and treatment goals.