Published 31 October 2026 · Reviewed by Dr Sin Yong
What to expect at a Rejuran visit with Dr Sin Yong starts with the skin and a direct question about fish allergy, because the polynucleotide is purified from salmon DNA. The preparation is chosen, topical anaesthetic is applied, the product is placed in the dermis by micro-injection, small papules appear at each point and flatten as it is taken up, and a review sets what follows.
Short answerA Rejuran facial is a medical injection, not a facial in the spa sense: Rejuran is registered with Singapore's Health Sciences Authority as an injectable medical device and is placed in the dermis by a doctor. The papules straight afterwards are expected. This page sits under Rejuran in Singapore.
Before any Rejuran is placed, Dr Sin Yong asks whether the problem is skin or structure. Rejuran is directed at how the skin repairs itself: texture, fine lines, elasticity and thin skin. It adds no volume, does not lift and does not remove pigment, so a hollow, a descended contour or a tethered scar needs a structural plan instead, and he says so.
Illustrative image — not a patient.
Fish allergy is asked about directly rather than assumed absent, because the active material is polynucleotide purified from salmon DNA, filtered and sterilised so that what is injected is the polymer, not genetic information. Before the visit:
Tell the clinic about any fish or seafood allergy.
Declare all medicines, especially blood thinners, and any keloid history. Never stop a prescribed medicine on your own for a cosmetic treatment.
Tell the clinic if you are pregnant, breastfeeding or planning pregnancy.
Avoid sun exposure, tanning and strong actives such as retinoids before the visit, as advised.
Bring photos, a list of skincare products and details of previous injectable treatments.
Which Rejuran preparation is used, and how is it placed?
The preparation is chosen at examination, by the skin and the area.
Preparation
What it is
Where it is placed
Healer
The standard facial preparation, polynucleotide at about 20 mg/mL
Intradermally across the face
S
A higher-viscosity preparation for scarred skin
Into and around scars, alongside structural scar work
I
A lower-viscosity preparation for thin skin
The periorbital area
HB
Polynucleotide combined with hyaluronic acid
Decided at examination
Topical anaesthetic is usual. Delivery is then by fine needle in a distributed pattern of micro-injections, or by an injector device placing small volumes at a set depth; which is used depends on the area. Most people describe a series of small pricks with some stinging, and the skin around the eyes and over scars tends to be more sensitive. Comfort is checked as the treatment goes on, and you can ask to pause.
Small papules or wheals appear at the injection points as the material sits. That is the expected appearance, not a complication.
“Nobody is injecting fish into your face. What is in the syringe is purified DNA fragments, and the allergy question is still asked every time.”
Dr Sin YongOn the first question at a Rejuran visit
What happens straight after Rejuran, and what needs a call?
These are phases, not a timetable: how quickly each passes depends on the area and the person.
Immediately after. Small papules or wheals at each injection point, with redness and sometimes bruising, more so around the eyes where the skin is thin.
The first evening. Avoid make-up, heat, alcohol and vigorous exercise. A cool compress eases swelling, and the papules begin to flatten.
The following phase. The papules settle as the polynucleotide is taken up; bruising fades on its own and the skin looks ordinary again.
As the skin settles. Changes in texture and hydration develop gradually rather than on the day; the early papules are not the result.
Polynucleotides tend to leave more visible bumps at first than a hyaluronic acid booster, so plan around them.
What needs a call
Pain that increases instead of settling, or skin that turns pale, dusky or mottled: urgent assessment by the doctor who injected you, or at A&E, now.
A bump that is red, hot, painful or swollen, a fever, or swelling that does not subside: a doctor the same day; if no doctor can see you today, A&E.
The plan is set individually at review rather than quoted in advance. Dr Sin Yong examines the skin once the papules have gone, because the early bumps say nothing about the result, and decides what follows: nothing further, another placement, or a different treatment alongside.
A bump that is still there once the rest of the skin has settled is scanned before anything is decided. Ultrasound shows where the product sits, how deep it is and how far it has spread, and whether filler or another booster placed earlier sits in the same area. How a lasting bump is treated without surgery is on skin booster lumps.
For post-acne skin, Rejuran is often paired with resurfacing or RF microneedling, because a polynucleotide addresses skin quality while tethered or fixed-wall scars need subcision or resurfacing; see Rejuran S for acne scars. The order and spacing are set so that each treatment is given at a sensible point in healing. The evidence base is still developing: a 2025 systematic review found nine studies of polynucleotide injections, all of low or moderate quality, with side effects generally mild and transient and little agreement on injection areas and technique.
Your next step
1. MessageWhatsApp +65 8023 7170 with what is bothering you. A reply comes from the clinic, not a bot.
2. AssessmentDr Sin Yong examines you himself on Orchard Road, with ultrasound where earlier filler is involved.
3. A plan in writingWhat he would do, what he would not, the fee factors, and the option of no treatment.
Every treatment is performed by Dr Sin Yong personally. Singapore Medical Council registered · invited to share his clinical expertise internationally for CLASSYS, DEKA, Fotona, Hironic and Ilooda.
Book an assessment with Dr Sin Yong on Orchard Road; tell the clinic about any fish or seafood allergy when you book. How consultations work.
Topical anaesthetic is usually applied first, and most people describe Rejuran as a series of small pricks with some stinging. The skin around the eyes and over scars tends to be more sensitive than the cheeks. Comfort is checked as the micro-injections are placed, and you can ask Dr Sin Yong to pause at any point during the treatment.
Small papules or wheals at each injection point are the expected appearance after Rejuran, because the material sits in the dermis where it was placed. Polynucleotides tend to leave more visible bumps at first than a hyaluronic acid booster. The bumps flatten as swelling settles and the polynucleotide is taken up; a bump that persists once the skin has settled is scanned.
A fish or salmon allergy is a reason to assess carefully or choose a different skin booster, because Rejuran's polynucleotide is purified from salmon DNA. Allergic reaction is rare, which is exactly why the question is asked directly rather than assumed. Tell the clinic about any fish or seafood allergy before the visit, along with other allergies and medicines.
No. A Rejuran facial at a medical clinic means polynucleotide placed into the dermis by micro-injection, which in Singapore is a medical treatment performed by a doctor. Salon facials that apply polynucleotide or salmon DNA serums to the surface do not deliver the same material to the same depth, and findings from studies of the injectable cannot be transferred to them.
Avoid make-up on the first evening, along with heat, alcohol and vigorous exercise, while the papules are present and the injection points are fresh. Once the points have closed and the papules are settling, make-up can usually resume. The specific make-up, cleansing and sunscreen instructions are given on the day and are set out on the aftercare page.
References
The Effectiveness of Polynucleotides in Esthetic Medicine: A Systematic Review. Journal of Cosmetic Dermatology 24(2), 2025. source
Comparison of the effects of polynucleotide and hyaluronic acid fillers on periocular rejuvenation: a randomized, double-blind, split-face trial. Journal of Dermatological Treatment 33(1), 2022. source
About this page: written and medically reviewed by Dr Sin Yong, MBBS (NUS), MRCS (Edinburgh) · Last reviewed 6 November 2026 · Illustrative images only, not patients · Editorial policy
