Guide · Dissolving filler
Dissolve filler in Singapore: how hyaluronidase works, and why assessment comes first
Hyaluronic acid filler can be broken down with an enzyme, but only if it is hyaluronic acid, and only as well as the enzyme is placed. Here is what dissolving involves, step by step, and what to ask before you agree to it.
Written & medically reviewed by Dr Sin Yong · 9 October 2026
Quick answer
- To dissolve filler in Singapore, a doctor injects hyaluronidase, a prescription enzyme, into unwanted hyaluronic acid (HA) filler. It breaks the gel down so the body can clear it, usually over a day to a few days. It does not dissolve non-HA fillers such as PLLA, PCL, calcium-based fillers, silicone or fat.
- Assessment comes first: what was injected, when and where, any allergy (especially to bee or wasp stings), and, where useful, ultrasound to see where the filler actually sits so the enzyme goes into the deposit and filler you want to keep can stay.
- Expect swelling, redness or itch for a day or two and possible bruising. A UK guideline suggests reassessing after about 48 hours, repeating if needed, and waiting at least two weeks before any new filler. Older or denser gels may need more than one round.
- Dissolving is performed by Dr Sin Yong at SkinRev Lab, CityLink Mall, and IN Eternity Clinic, Pacific Plaza, after a consultation, and is priced at consultation. A blocked blood vessel is different: it is an emergency, not a booked appointment.
Watch · Dr Sin Yong explains
The enzyme
What hyaluronidase is and how it dissolves filler
Hyaluronidase is an enzyme that cuts the long chains of hyaluronic acid into smaller pieces. Your body already makes its own hyaluronidases to turn over the natural HA in skin. The medical version, usually derived from animal sources or made by recombinant technology, has been used for decades in eye surgery and anaesthesia to help fluids spread, and it is now the standard way to reverse HA filler.
Cosmetic HA filler is cross-linked, meaning the HA chains are tied together so the gel lasts months to years instead of days. Hyaluronidase still finds binding sites within the gel, but how quickly it works depends on the HA concentration, the amount of cross-linking and the form of the gel. Laboratory and animal work suggests some gels dissolve readily at low doses while denser, monophasic gels need more enzyme or repeated rounds.
The enzyme does not last long in tissue. A review describes it as rapidly degraded and deactivated in the body, and one animal study found its activity fell away within about 30 minutes. That is why it has to be placed into or right next to the filler, rather than injected nearby and left to find its way.
HA only
Which fillers can be dissolved, and which cannot
Only hyaluronic acid filler responds to hyaluronidase. The majority of cosmetic fillers used on the face today are HA, but not all. Collagen biostimulators such as poly-L-lactic acid (PLLA) and polycaprolactone (PCL), calcium hydroxylapatite, non-absorbable materials such as silicone and polyacrylamide gel, and fat grafts do not respond to the enzyme at all.
This is why the first question is not how much enzyme to use, but what is actually there. People often do not know the product they received years ago, especially if treatment was abroad or at several clinics. Records help; when they are missing, the history and imaging help the doctor judge what is likely present.
If the material is not HA, the plan changes. Depending on what it is and how it behaves, options can include waiting, anti-inflammatory treatment for a reacting nodule, energy-based approaches, or referral to a plastic surgeon when removal needs surgery. For non-HA filler, Dr Sin Yong may consider his Time Freeze Laser LCLR® protocol, whose Sculpting mode his own site describes as taking away excess, including excess left by filler overfill; whether it suits is decided case by case.
| Material | Dissolves with hyaluronidase? | What usually happens instead |
|---|---|---|
| Hyaluronic acid (HA) filler | Yes | Targeted hyaluronidase, sometimes in more than one round |
| PLLA or PCL biostimulator | No | Assessment of the nodule or excess; time, medicines or other approaches |
| Calcium hydroxylapatite | No | Assessment; some cases are managed medically or surgically |
| Silicone, polyacrylamide gel | No | Specialist assessment; surgical removal is sometimes needed |
| Fat graft | No | Surgical opinion if fat needs reducing |
Imaging
Why ultrasound before dissolving helps
Filler rarely stays as one neat deposit. It can sit deeper or shallower than intended, spread along tissue planes, or build up in layers after several treatments. In an MRI review of 33 people who had mid-face HA filler, filler was still visible in every one of them at least two years after injection, and in some people up to 15 years later.
High-frequency ultrasound lets the doctor see this before treatment. HA usually shows up as dark, fluid-like pockets, and other materials have their own patterns, so the scan can also suggest when a lump is not HA. Researchers from Rotterdam describe using ultrasound to bring previous filler into view, map nearby blood vessels and inject hyaluronidase directly into the deposit.
Ultrasound does not make every case straightforward, and not every small, obvious lump needs a scan. But for an overfilled face, filler of unknown type, lumps under thin skin or filler near important vessels, imaging makes dissolving more precise and helps avoid treating areas that do not need it.
Allergy
Allergy history and the skin test question
Hyaluronidase is a protein, so allergy is possible. In aesthetic use, true allergic reactions are uncommon: a UK guideline found only a handful of published cases after dissolving filler, though the authors believe it is under-reported, and the reactions described are mainly localised swelling appearing an hour or more after injection rather than anaphylaxis.
Insect stings matter. Bee and wasp venom contain hyaluronidase. In a German study of 90 people with confirmed sting allergy, more than one in five of those allergic to wasps who had never had desensitisation tested positive to medical hyaluronidase on skin-prick testing; none of the healthy controls did. The authors advise that people with untreated sting allergy, especially to wasps, see an allergy specialist before having hyaluronidase.
Many clinics do a small skin test first. It can be useful, but it has limits: a review notes that delayed allergic reactions may not be predicted by skin tests, and the UK guideline points out that allergy societies do not recommend skin tests as routine screening without a relevant history. Your history is the starting point, and it shapes whether testing, specialist review or a different plan is sensible.
On the day
Dissolve filler in Singapore: what a visit involves
The amount of enzyme is not a fixed number per syringe of filler. The UK guideline recommends treating to effect, because different gels, different amounts and different ages of filler respond differently. A small lump might need a single small injection; an overfilled mid-face mapped on ultrasound may be treated area by area.
Some people prefer to dissolve everything and start again; others want only the problem area treated. Partial dissolving is possible when the enzyme is placed precisely, and it is often the more conservative choice.
- History: products, dates, areas, previous dissolving, medicines, allergies and any recent illness or dental work.
- Examination at rest and in movement, with photographs in consistent light.
- Ultrasound where useful, to locate the filler and nearby vessels.
- Allergy assessment, and a small test where appropriate.
- Numbing cream, then small amounts of enzyme placed into the unwanted filler through a fine needle or cannula.
- Aftercare advice and a review date.
Sessions
How many sessions, and when results settle
The enzyme starts working within hours, and the filler usually softens and reduces over a day to a few days. The UK guideline suggests reassessing after about 48 hours and repeating treatment if needed. Swelling from the injections themselves can take longer to settle, so the true result is judged at a review a couple of weeks later.
One session is enough for many small problems. Larger volumes, filler that has been in place for years, denser gels and filler spread across several areas more often need two or more rounds spaced apart. Staging also lets the face be reassessed before more is removed, which reduces the risk of overcorrection.
Hyaluronidase also breaks down some of your own natural HA in the treated area. This is temporary: the guideline notes that, given its rapid turnover, the body restores native HA within about 15 to 20 hours. A briefly flatter or hollower look in the first days is usually swelling and tissue rebalancing rather than the final result.
Risks
Swelling, bruising and other risks of dissolving
Common effects are swelling, redness, itch or tenderness at the injection sites for a day or two, small needle marks and sometimes bruising. With higher doses, a non-allergic injection-site reaction with redness and swelling that settles within about 24 hours can occur.
Less common problems include an allergic reaction, which can be local swelling or, rarely, a more serious reaction; dissolving more than intended, which can leave an area flatter than you would like; and, where a lot of filler had stretched the skin, a looser look once the volume is gone. Not every irregularity resolves in one round.
The evidence base has gaps. A scoping review found that randomised trials of hyaluronidase involved small HA nodules on the arm or back rather than the face, and that facial dissolving relies on case series, guidelines and clinical experience. Results vary from person to person, and an honest plan says so.
Not for everyone
Who should not have filler dissolved, or should wait
Sometimes the honest answer is no treatment. A small, soft irregularity that you can barely see may not be worth an injection, and a result that looks wrong only in one unflattering photo may simply need time.
If a lump is inflamed, tender or appeared months after filler, it may be a delayed inflammatory reaction, which is assessed differently and may need medicines as well as or instead of the enzyme. When surgery or a dermatologist's opinion is the better route, that should be said plainly.
- Known allergy to hyaluronidase: a different plan is needed.
- Untreated bee or wasp sting allergy, especially to wasps: allergy specialist review first.
- Pregnancy: dissolving is not advised; non-urgent correction can wait.
- Active infection or broken skin in the area: treated first.
- Filler that is not HA: the enzyme will not help.
- Puffiness from fluid retention, thyroid problems or other medical causes: these need their own assessment.
Emergency
When dissolving filler is urgent
Rarely, filler blocks a blood vessel. Warning signs are skin near a recent injection turning pale, white, blotchy or dusky, pain that is increasing rather than settling, and, very rarely, any change in vision. This is not a routine dissolving appointment; it needs immediate medical attention.
Vascular occlusion is treated with higher doses of hyaluronidase to flood the affected area. In a 2026 meta-analysis of 231 patients with HA filler-related vascular complications, treatment within six hours was linked with better outcomes. If you notice these signs, contact the clinic that treated you at once, or go to a hospital emergency department; for any change in vision, call 995.
At SkinRev Lab
Dissolving filler with Dr Sin Yong at SkinRev Lab
Filler dissolving is a medical treatment performed by Dr Sin Yong, SkinRev Lab's doctor, at SkinRev Lab, #B1-28 CityLink Mall, on the underground link to City Hall and Esplanade MRT (open daily, 11am to 8pm), and at IN Eternity Clinic, 9 Scotts Road, Pacific Plaza, Orchard. Hyaluronidase is a prescription-only medicine and is given only after a consultation and assessment.
At the consultation he takes your filler history, examines your face and, where useful, scans it with ultrasound, because his approach is to image earlier filler before anything is dissolved or added, and to treat the layer that changed. The options he discusses include partial dissolving, staged dissolving, a non-HA plan, referral, and no treatment at all. Treatment is priced at consultation, once the areas and likely number of sessions are clear. To book, WhatsApp SkinRev Lab on +65 8266 9585.
Sources
References & sources
- Murray G, Convery C, Walker L, Davies E. Guideline for the safe use of hyaluronidase in aesthetic medicine, including modified high-dose protocol. J Clin Aesthet Dermatol. 2021;14(8):E69-E75.
- Jung H. Hyaluronidase: an overview of its properties, applications, and side effects. Arch Plast Surg. 2020;47(4):297-300.
- Hong GW, Hu H, Wan J, et al. How should we use hyaluronidase for dissolving hyaluronic acid fillers? J Cosmet Dermatol. 2025;24(1):e16783.
- Schelke LW, Decates TS, Velthuis PJ. Ultrasound to improve the safety of hyaluronic acid filler treatments. J Cosmet Dermatol. 2018;17(6):1019-1024.
- Master M, Azizeddin A, Master V. Hyaluronic acid filler longevity in the mid-face: a review of 33 magnetic resonance imaging studies. Plast Reconstr Surg Glob Open. 2024;12(7):e5934.
- Bertlich M, Hartmann D, Freytag S, French LE, Oppel E. Sensitization against medical hyaluronidase in patients with confirmed hypersensitivity against hymenoptera species and its clinical implications. Br J Dermatol. 2024;191(6):1000-1007.
- Borzabadi-Farahani A, Mosahebi A, Zargaran D. A scoping review of hyaluronidase use in managing the complications of aesthetic interventions. Aesthetic Plast Surg. 2024;48(6):1193-1209.
- Alhusain AM, Alsaif M, Alkhathami AM, et al. Hyaluronidase protocol in management of hyaluronic acid filler-related vascular complications: a systematic review and meta-analysis. Aesthetic Plast Surg. 2026;50(6):2300-2317.
Common questions
Your questions,
answered
How long does hyaluronidase take to dissolve filler?
The enzyme starts working within hours, and filler usually softens and reduces over a day to a few days. Swelling from the injections can last a little longer, so the result is judged at a review about two weeks later.
Can all filler be dissolved?
No. Only hyaluronic acid filler responds to hyaluronidase. PLLA, PCL, calcium hydroxylapatite, silicone, polyacrylamide gel and fat do not, so knowing what was injected comes first.
Will dissolving filler make my face look older?
In the first days some areas can look flatter while swelling settles and native HA is restored, which takes about 15 to 20 hours. If a lot of filler had stretched the skin, it may look a little looser. Targeted, staged dissolving reduces the chance of removing more than needed.
Is dissolving filler painful?
Numbing cream is used, and many people describe stinging or pressure during the injections. Tenderness for a day or two is common. How it feels varies from person to person.
How many sessions will I need?
Small lumps often need one. Larger amounts, older or denser filler and several areas more often need two or more rounds, spaced so the face can be reassessed in between.
Do I need a skin test?
It depends on your history. A small test is often done, but it cannot rule out delayed reactions. If you have an untreated bee or wasp sting allergy, an allergy specialist review is advised before hyaluronidase.
Can I dissolve just part of my filler?
Yes, if the enzyme is placed precisely into the problem deposit. Ultrasound helps locate it, so filler you want to keep can usually stay.
When can I have filler again after dissolving?
A UK guideline recommends at least two weeks, and longer if swelling persists. Many people find they need much less than before, or none.
Can I dissolve filler that was done overseas?
Yes, if it is HA. Bring any records of the product and dates. If the type is unknown, the history and ultrasound help judge what is there before any enzyme is used.
Is dissolving filler the same as treating a blocked vessel?
No. Elective dissolving is planned after assessment. A blocked vessel is an emergency treated straight away with higher doses; signs include pale or dusky skin, worsening pain or vision change.