Rejuran Singapore: What Polynucleotides Actually Do, Who They Suit, and What Results to Expect

Most patients arrive at a Rejuran consultation having read that it is a “salmon DNA injection” without knowing what that means clinically. Some expect it to fill a line the way a dermal filler would. Others expect it to lift in the way that treatments such as Ultherapy or Thermage can. A third group has been told it will erase acne scars in one session. These are different treatment goals, and Rejuran should not be expected to do all of them.

Rejuran has a narrower role. It is an injectable polynucleotide treatment used primarily to improve skin quality rather than to create substantial volume or mechanically lift descended tissue. Clinical studies of injectable polynucleotides have reported improvements in measures such as hydration, elasticity, texture, roughness and overall skin appearance, although the evidence base remains smaller than that for many established aesthetic treatments.

This article covers what the injectable contains, how to work out whether it matches the problem you are trying to treat, how it can fit alongside laser and energy-based treatments, what a typical treatment course looks like, what drives the price in Singapore, and what constitutes a realistic result over several months rather than several days.

First, the terminology, because the market gets it wrong

Rejuran’s injectable products contain PN, or polynucleotides. The manufacturer describes Rejuran as containing purified long-chain polynucleotides derived from salmon DNA and produced using its proprietary DOT technology.

PDRN, or polydeoxyribonucleotide, is a related DNA-derived material, but the terms PN and PDRN should not automatically be used interchangeably. Rejuran’s injectable Healer line is marketed as a PN product, while Rejuran’s separate cosmetic skincare range contains c-PDRN.

This distinction matters clinically. A topical skincare product and an intradermal injectable differ in concentration, formulation, delivery depth and supporting evidence. A product from the Rejuran skincare range should therefore not be considered interchangeable with an injectable Rejuran treatment.

The same principle applies when comparing Rejuran with other injectable polynucleotide products. Different PN products can vary in concentration, molecular characteristics, source, purification technology and intended treatment protocol. The clinically useful comparison is therefore between the actual products and their indications rather than reducing the discussion to “PDRN versus PN”. Our comparison of Plinest and Rejuran covers those differences in more detail.

The diagnostic question: is your problem structure, volume, or skin quality

Before naming an injectable, it helps to work out what is actually producing the concern. In practice, several problems often coexist, which is why one treatment does not necessarily solve everything a patient sees in the mirror.

Structure. The tissue has descended or the scaffolding has weakened. Jowls, a heavier lower face, a flattened cheek that used to be full. Structure problems respond to lifting energy such as Ultherapy or Thermage, to collagen stimulators, or in some cases to surgery. A polynucleotide will not correct them, and no honest course of Rejuran will be sold as though it might.

Volume. Something is hollow. Under-eye hollowing, temples, mid-face flattening. Volume problems respond to products that occupy space or that stimulate the body to build it. Again, not the job of a polynucleotide.

Skin quality. The face has not descended and is not hollow, but the skin itself looks tired. Fine crepe texture across the cheek. Dullness that does not lift with exfoliation. Enlarged pores. Skin that flushes and stays flushed. Post-inflammatory skin after a long acne course. Skin that heals slowly after laser. Skin that looks visibly worse in the week before a period. This is where polynucleotides are generally most relevant. Concerns may include fine crepey texture, dullness, early fine lines, reduced elasticity, visible pores or skin that looks less resilient than it used to. Clinical studies of injectable PN products have reported improvements across several skin-quality parameters, although individual response varies.

A practical self-check: pinch the skin on your cheek gently and let go. If the concern is that the skin felt thin and papery between your fingers, that is a quality question. If the concern is that there was more skin than there used to be, that is a structure question. Most patients over thirty-five have some of both, which is why single-modality plans underdeliver.

The mechanism, in the order it happens

Polynucleotides are placed intradermally, in a grid of small injection points across the treatment area, rather than in a single bolus. What follows is not primarily a filling effect. It is a signalling and skin-repair effect.

The fragments interact with fibroblasts, the cells responsible for producing collagen, elastin and other components of the extracellular matrix that support the dermis. Laboratory and clinical research suggests that polynucleotides can support fibroblast activity and tissue repair, with downstream effects on collagen production and the extracellular matrix. The manufacturer’s own positioning describes the product as supporting the repair of skin affected by the external environment and by energy-based treatments. The important distinction is that Rejuran is not replacing lost collagen directly. It is intended to support the biological processes involved in repairing and maintaining the dermis.

Alongside that is a hydration effect. Polynucleotides have water-binding properties, and improved skin hydration is one of the changes reported after treatment. Patients may notice, in the first few weeks, that the skin looks better hydrated and slightly plumper in a way that is not the same as adding volume with filler. This is usually one of the earlier changes, while improvements in texture and elasticity take longer to assess.

The remodelling component is slower and more modest. Changes in collagen and the extracellular matrix develop over time and are better judged across a treatment course rather than after a single session. This is why one session gives an incomplete picture of what Rejuran can do, and why patients who see an early improvement that then softens may conclude, reasonably but prematurely, that the treatment does not work.

Why this matters more in Singapore than in a temperate climate

Two local factors change the calculation.

The first is cumulative ultraviolet exposure. Singapore experiences very high and, at times, extreme UV levels throughout the year, with no winter season to substantially interrupt that exposure. Chronic UV exposure damages collagen and other components of the dermal matrix and impairs normal fibroblast function, which is relevant when the treatment goal is to improve skin quality and support dermal repair. A patient who has spent decades in Singapore may therefore have a different cumulative UV history from someone of the same age living in a lower-UV, four-season climate.

The second is skin type. Many patients treated in Singapore have more pigment-reactive skin, and the practical consequence is a greater risk of post-inflammatory hyperpigmentation after inflammatory procedures, including aggressive laser treatments. That risk shapes how aggressively a doctor can treat in a single session. It often pushes protocols towards a sequence of controlled, better-tolerated interventions rather than one dramatic one, and polynucleotides can be useful as a skin-quality and recovery layer within that sequence.

There is also a humidity point that cuts against the marketing. In Singapore’s humid climate, patients often assume their skin must already be adequately hydrated and that a hydration-focused treatment is redundant. It is not that simple. High ambient humidity does not guarantee good skin hydration, particularly when much of the day is spent in air-conditioned environments. Surface oil is also not the same as skin hydration, which is why oily skin can stil; be dehydrated.

Who the treatment suits, and who it does not

At Dr Cindy’s Medical Aesthetics, polynucleotides are used in four situations where the clinical case is strongest.

Post-inflammatory skin after acne. A patient who has finished an active acne course is often left with skin that is no longer breaking out but is still red, uneven in texture, and slow to settle. Polynucleotides can be used at this stage to support skin quality and recovery. This is not scar correction. Established acne scars are a structural problem that requires a different treatment approach, and it is worth reading our guidance on matching acne scar treatments to scar type if structural scarring is the actual concern.

As a scar-protocol adjunct. In atrophic scarring, the sequence matters more than any single treatment. Subcision releases tethered scars, while fractional laser or RF microneedling stimulates remodelling at controlled depths. A polynucleotide injectable can then be used alongside these treatments to support skin quality and recovery during the healing phase. The injectable is not the scar treatment on its own. Its role is to support the skin while the structural treatments do the heavier work.

Recovery after energy-based treatments. Patients on a laser or radiofrequency course, including Ultherapy, Thermage or RF Microneedling, often benefit from a repair layer between sessions.

Early skin-quality decline in the thirties and forties. Texture, dullness and early fine lines with no meaningful descent yet.

It suits poorly in three situations. If the primary complaint is descent or laxity, a polynucleotide is the wrong tool and should not be the plan on its own. If the primary complaint is a static line already etched into the skin at rest, expect limited improvement. And if you are unwilling to complete the recommended course, the money may be better spent elsewhere, because the cumulative improvement in skin quality is better judged across a course than after a single session.

The course, the interval, and what happens at each stage

A standard course is three to four sessions. At the clinic, the interval between sessions in the active phase is typically four weeks. This gives the skin time to respond between treatments and allows the result to build progressively across the course. Published polynucleotide protocols use different intervals, so four weeks is a treatment protocol rather than a fixed biological requirement. Maintenance sessions afterwards sit at longer intervals and are adjusted according to how the skin responds.

The session itself takes around twenty to thirty minutes, depending on the treatment area and numbing time. Topical anaesthetic goes on first. The injections are small-volume intradermal placements in a grid across the area. Patients describe it as tolerable rather than comfortable, and it is generally more felt than a laser and less felt than subcision.

Immediately afterwards there are small raised papules at each injection point. These are expected after intradermal injection, not a complication. They usually settle within several hours to a day, although this varies with placement depth, treatment area and the individual. Bruising is possible, particularly under the eyes and around the temples. This is the practical reason to book at least a week before anything photographed.

What patients notice, and when:

Weeks one to three. Hydration and a slight plumpness are often among the earliest changes. Makeup may sit differently and the skin may look smoother. These early changes should not be mistaken for the final result.

Weeks four to eight, across sessions two and three. Changes in texture and overall skin quality may become easier to see. Pores may look less prominent, and the skin may appear smoother and more even.

Months three to six. The cumulative result of the course is clearer. Improvements in texture, elasticity and overall skin quality can persist for several months, although the degree and duration vary between patients.

Assessing the result at three weeks after one session gives an incomplete picture of the treatment. The early visible change may be driven largely by improved hydration, while changes in texture, elasticity and overall skin quality are better judged across the full course.

Sequencing with the rest of a treatment plan

Polynucleotides are rarely the whole plan, and they are not intended to be. The sequencing questions patients ask most often have consistent principles, even when the exact answer depends on what they are being combined with.

Laser or injectable first? It depends on the device. When an energy-based treatment deliberately creates controlled inflammation or injury, the timing of the injectable needs to account for how the skin is expected to recover. In many treatment plans the device comes first and the polynucleotide is used afterwards as part of the recovery and skin-quality phase, but this is not a fixed rule for every device or every patient.

Can they be combined in one session? Sometimes, and it depends on the device, the treatment depth and the degree of inflammation expected. This is a judgement made at consultation, not a rule.

Alongside pigmentation work? Yes, and this is where the plan gets genuinely useful. Melasma is not simply excess pigment sitting at the surface. Changes involving the basement membrane, dermal matrix and vascular environment can sit alongside the pigment itself, which is one reason melasma can be difficult to treat and quick to recur. RF Microneedling can be used selectively in some melasma protocols, but it needs to be approached carefully because excessive inflammation can worsen pigmentation in susceptible skin. A polynucleotide can sit alongside that work as a skin-quality and recovery treatment rather than replacing pigment-directed treatment. Our melasma treatment guide sets out that clinical framework in full.

Alongside topicals? Yes, and the topical regimen does most of the daily work. For pigment-involved cases at the clinic, that may include cysteamine such as Cyspera Original+, a retinoid or retinoid derivative where appropriate, niacinamide, and daily tinted SPF 50. Oral sun-protection supplements such as Crystal Tomato or Heliocare may also be used as adjuncts from the start of the treatment cycle rather than held back for maintenance. They do not replace sunscreen. Topical sunscreen remains the foundation of photoprotection, but in practice it is frequently under-applied and under-reapplied through a normal Singapore day, which is why the clinic takes a layered approach to sun protection.

What it costs in Singapore, and what actually drives the number

Approximate market ranges across reputable medical aesthetic clinics in Singapore run roughly S$800 to S$1,200 per session for a single-vial facial treatment, with a three-session course typically quoted between S$2,400 and S$3,600. Multi-vial protocols and combined-area treatments sit above that. Our price guide breaks the figures down further.

What moves the number:

Number of vials per session. A full-face treatment and a targeted under-eye treatment are not the same volume of product, and quotes are not comparable unless the vial count is stated.

Whether a doctor injects. Intradermal placement depth is the whole treatment. Too superficial produces persistent papules and visible unevenness; too deep wastes the product in tissue where it does not do the intended job.

Product provenance. Ask which product, which line, and to see the packaging. Injectable and topical lines share brand names, and the injectable is the one with the clinical evidence behind the course you are paying for.

Whether the price includes the course or one session. A per-session price against a course price is the most common apples-to-oranges comparison patients make.

Pricing meaningfully below the market range should prompt questions rather than enthusiasm. The usual explanations are fewer vials, a non-medical injector, or a different product entirely.

Realistic expectations, stated plainly

Polynucleotides improve skin quality. Patients may notice better hydration, smoother texture, improved elasticity and skin that looks healthier overall. These changes are subtle rather than structural, and for the right candidate they can make the course worthwhile.

They do not lift. They do not fill. They do not remove established scars. They do not cure acne. They do not replace sun protection, and a course undertaken alongside substantial unprotected UV exposure in this climate is working against the broader skin-quality goal.

The improvement is real and partial. Skin quality is maintained rather than permanently fixed, which is why maintenance intervals exist. A patient who completes a course and then stops treatment does not suddenly lose the result, but the effects gradually diminish over time as normal aging, UV exposure and other environmental factors continue.

What the consultation involves

A first consultation should separate the three problems named earlier before any product is discussed. That means a clinical history including acne history, prior treatments, medications and photoprotection habits; visual examination; assessment of skin type and pigment reactivity, because both influence treatment choice and risk; and, where pigmentation is part of the picture, further assessment to understand whether the pigment is predominantly epidermal, dermal or mixed. A Wood’s lamp can sometimes help with that assessment, but it should be interpreted alongside the clinical examination rather than used as a definitive measure of pigment depth.

You should leave knowing which of the three problems you actually have, whether a polynucleotide addresses it, how many sessions are proposed and at what interval, what the total cost of the course is rather than the per-session figure, what a realistic result looks like over the following months, and what the plan is if the response is weaker than expected. If a consultation produces a product recommendation without a diagnosis, that is a reason to ask more questions. Treatment details are on our Rejuran service page.

Frequently asked questions

What is Rejuran, in one sentence?

It is an injectable polynucleotide treatment, placed intradermally across the treatment area, that supports fibroblast activity, tissue repair and skin hydration. It improves skin quality, including texture, elasticity and overall skin appearance. It does not lift, fill or resurface.

Is Rejuran PN or PDRN?

The injectable is PN, polynucleotides, derived from salmon DNA and made using the manufacturer’s proprietary DOT technology. PDRN is a related DNA-derived material and is also used in products within Rejuran’s separately sold topical skincare line. The two are frequently confused, including by clinics, but a topical product and an intradermal injectable should not be treated as interchangeable.

How long does it last?

The hydrating component may become noticeable within the first few weeks, while changes in texture and elasticity accumulate across a three to four session course. Clinical studies have reported improvements persisting for several months after a course, although there is no single duration that applies to every patient. Longevity varies with the individual, baseline skin condition, treatment protocol and ongoing environmental exposure.

How often should I have it?

Four-week intervals during the active course of three to four sessions, then maintenance at longer intervals depending on how the skin holds. Four weeks is the clinic’s active-phase protocol, although published polynucleotide studies have used different treatment intervals.

Does it help acne scars?

It has a genuine role in a scar protocol and it is not a scar treatment on its own. In atrophic scarring, subcision releases tethering, while a fractional device can stimulate remodelling at controlled depths. A polynucleotide injectable can then support skin quality and recovery through the healing phase. Expect the injectable to complement what the other steps achieve, not to correct a scar independently.

Rejuran or Profhilo?

They answer different questions. A polynucleotide addresses skin quality and repair. Profhilo is a bioremodelling hyaluronic acid used for hydration with mild improvement in skin laxity across a wider area. A patient whose complaint is dull, post-inflammatory skin and a patient whose complaint is generalised dryness with mild early laxity are not the same case. Some patients may be advised to have both as part of the same treatment plan. Our side-by-side comparison goes through the differences.

What are the side effects?

Small raised papules at each injection point, expected and usually settling within several hours to a day. Bruising, particularly around the eyes and temples. Transient redness and mild swelling. Tenderness for a day or two. Papules that persist longer than expected should be reviewed by the treating doctor rather than assumed to be a technique issue.

Can I have it while pregnant or breastfeeding?

No. Elective aesthetic injectables are not administered during pregnancy or breastfeeding at the clinic. Tell the doctor at consultation if either applies or may apply.

What happens at Dr Cindy’s Medical Aesthetics if my skin does not respond?

The plan is reassessed rather than repeated. A weak response after two sessions usually means the original diagnosis weighted skin quality when the dominant problem was structure or pigment, or that photoprotection is not holding. The clinic’s approach is to re-diagnose and change modality rather than continue a course that is not producing change.

References

Squadrito F et al., “Pharmacological Aspects and Clinical Applications of Polydeoxyribonucleotide”, Frontiers in Pharmacology, 2017 (https://www.frontiersin.org/articles/10.3389/fphar.2017.00224/full)

Vashi NA, Kundu RV, “Facial hyperpigmentation: causes and treatment”, British Journal of Dermatology, 2013 (https://onlinelibrary.wiley.com/doi/10.1111/bjd.12536)

National Environment Agency Singapore, UV index measurement and health advisory, 2026 (https://www.nea.gov.sg/weather/ultraviolet-index)

Polynucleotides sit in the skin-quality layer of a treatment plan at Dr Cindy’s Medical Aesthetics, where Dr Cindy has practised aesthetic medicine for 20 years. The consultation begins by establishing which of structure, volume or skin quality is actually driving your concern, because the answer decides whether this is the right treatment for you at all.