Radiesse in Singapore: CaHA filler, hyperdilution, lumps and the risks to know

The basics

What Radiesse is: calcium hydroxylapatite in a gel

Radiesse is a brand of calcium hydroxylapatite (CaHA) filler. CaHA is a mineral that occurs naturally in bone and teeth; in the product it is made synthetically as tiny, smooth microspheres suspended in a gel carrier of sodium carboxymethylcellulose. It contains no animal-derived material. A version premixed with lidocaine, a local anaesthetic, is also used.

CaHA was used in medicine before aesthetics, and in the United States it was approved in 2006 for moderate to severe wrinkles and folds. It is now used to restore volume in the mid and lower face and on the backs of the hands, and, when diluted, to improve skin quality on the face and body. It is a medical device injected by a doctor.

The brand name is used on this page only because it is what people search for. We do not promote any product, and the same principles apply to other CaHA fillers.

Mechanism

How CaHA works: filler first, then collagen

Undiluted CaHA is a thick, firm gel with high viscosity and stiffness, so it stays where it is placed and gives lift and projection straight away. Over the following weeks to months, the gel carrier is absorbed. The microspheres remain for longer, and cells gather around them and lay down new collagen, so part of the early volume is gradually replaced by your own tissue. The microspheres themselves are broken down slowly.

How long it lasts depends on the area, the amount and the person. An evidence review describes initial volume lasting up to about 12 months, followed by longer-term correction from collagen, and figures of 12 to 18 months are commonly quoted. In a follow-up of 102 people treated for nasolabial folds, 40% of folds were still rated improved at least 30 months after the last treatment, so a minority keep a visible effect for longer. A review of filler degradation notes that CaHA usually persists for up to two years, and in some people for more than five.

That persistence cuts both ways. Longer-lasting is not automatically better: it also means living longer with any misjudgement, and unlike hyaluronic acid filler there is no enzyme to reverse it.

Dilution

Diluted and hyperdilute CaHA: a different treatment

The same product behaves very differently depending on how much it is diluted. Practical guidance from a panel of 12 experienced injectors describes three broad uses. Undiluted CaHA is placed deep, on bone or under the skin, for volume. At 1:1, for example 1.5 mL of CaHA mixed with 1.5 mL of diluent, it has intermediate stiffness and still restores some volume, for instance on the backs of the hands. At 1:2 or more, for example 1.5 mL with 3 mL or more of diluent, it has negligible lifting properties and acts only as a biostimulator.

Hyperdilute CaHA is spread thinly at the junction between the skin and the fat beneath it, across a wide area, to improve skin quality and mild laxity on the face, neck, décolletage, arms and other body areas. The panel suggested more dilution for thinner skin, to avoid visible or palpable product: 1:2 to 1:3 for normal skin, 1:4 for thin skin and 1:6 for atrophic skin, usually injected with a cannula through few entry points.

Two caveats. This guidance reflects expert experience rather than controlled trials, and the evidence for hyperdilute use is still developing. And even very dilute product cannot be dissolved, so uneven placement can leave product that is visible or palpable; it is not a casual 'skin booster'. Hyperdilute CaHA cannot fill a hollow, and changes in skin quality build over weeks to months.

Compared

Radiesse vs HA filler, and vs PLLA and PCL

Hyaluronic acid (HA) filler is a water-binding gel that fills space on the day and can be dissolved with hyaluronidase. CaHA is firmer, gives immediate lift and then adds a collagen phase, and cannot be dissolved. A 2013 evidence review described CaHA's safety and tolerability as comparable to HA when used appropriately, but classed it as an adjustable filler, whereas HA is fully reversible.

Poly-L-lactic acid (PLLA, for example Sculptra) is a powder mixed with water. Apart from early swelling, it adds no immediate volume, and collagen builds over months across a course of sessions. Polycaprolactone (PCL, for example Ellansé) is the closest in design to CaHA: polymer microspheres in a carboxymethylcellulose gel that gives some shape at first and is absorbed over two to three months while collagen forms. CaHA and PCL differ in particle material and in how long they are designed to last.

Which suits you depends on the area, how quickly you want to see change, and how much you value being able to undo it. For a first injectable or a precise change in a small area, HA filler is often the starting point because it is reversible.

Reversibility

Why hyaluronidase does not dissolve Radiesse

Hyaluronidase is an enzyme that cuts the bonds between the sugar units of hyaluronic acid. CaHA is a mineral and its gel carrier is a cellulose derivative, so the enzyme has nothing to act on. This matters if you are not sure what you were injected with: hyaluronidase given for a CaHA lump will not shrink it, so identifying the material first, from records or ultrasound, avoids an unnecessary injection. A review of filler degradation describes CaHA as broken down slowly in the body by hydrolysis and by enzymes from bone-resorbing cells, not by hyaluronidase.

Sodium thiosulfate, a calcium-binding drug used for calciphylaxis, a rare condition of calcium deposits in small blood vessels, has been proposed as a reversal agent. In a laboratory and cadaver study, it disintegrated CaHA in direct contact, but it did not dissolve CaHA lodged inside facial artery segments after 24 hours, and the authors concluded that CaHA still lacks a suitable antidote. A separate preclinical study found no sign that it degraded the microspheres; reductions in volume looked more like the product being dispersed, and areas of tissue necrosis and bleeding were seen after injection.

Its use for CaHA is off-label, meaning it is not licensed for this purpose. Small pilot studies have suggested smaller nodules or less volume after injection into the lump, and a 2024 review summarised it as slow-acting and not effective in an emergency. It may be one option a doctor discusses for a stubborn nodule, with the uncertainty explained, but it is not a way to reverse Radiesse on request.

Lumps

Radiesse lumps, nodules or overcorrection: what can be done

Nodules are the side effect reported far more often than any other with CaHA. A review of 21 studies covering 5,081 treatments in 2,779 patients found adverse events in 3%, and 96% of these were nodules. About half of the nodules were in 'dynamic' areas that move a lot, such as around the mouth. The review noted that in the majority of cases, CaHA nodules are not visible and resolve without intervention.

Timing helps to tell lumps apart. Firm lumps soon after treatment usually reflect too much product in one spot or placement that is too superficial. Lumps that appear months later, especially if red, tender or growing, are rarer and need a doctor's assessment, because inflammation or infection has to be excluded before anything else is done. Ultrasound can show where the material sits and how much there is.

Approaches described in the literature include waiting, massage soon after treatment, injection of saline or a steroid into a persistent nodule, off-label sodium thiosulfate with the limits explained above, and surgical removal of a discrete lump that does not respond, for which a plastic surgeon's opinion may be appropriate. On drsinyong.com, Dr Sin Yong describes mapping non-HA filler with ultrasound and then using the Sculpting mode of his Time Freeze Laser LCLR® protocol to take away the excess. This is his clinical protocol rather than something tested in published trials; it can remove more fat in a zone than intended, and it does not suit lean faces where removing tissue would not help.

If the problem is overcorrection rather than a lump, the first step is usually time: early swelling settles and the gel carrier is absorbed over weeks to months. Adding more product, of any kind, to balance it out is rarely the answer.

Placement

Where Radiesse is generally not used: lips and tear trough

In a series of 1,000 patients treated with CaHA over 52 months, nodules were rare and were chiefly confined to the lips; only two patients developed nodules outside the lips. An evidence review concluded that because CaHA cannot be reversed with an enzyme and is viscous and elastic, consensus suggests avoiding highly mobile areas such as the lips and anatomically unforgiving areas such as the region around the eyes, where nodules may be more frequent.

Hyperdilution guidance makes a similar point: avoid placing CaHA over the ring-shaped muscles around the eyes and mouth, where the skin is closely attached to muscle and product tends to collect. The tear trough has thin skin and little fat, so any firm, white product is more likely to be seen or felt. Some doctors have published experience with CaHA around the eyes, but if a lump forms there, the options are limited.

If you want the lips or under-eyes treated, the discussion is usually about HA filler, which can be dissolved, or about whether filler is needed at all. HA in the tear trough has its own pitfalls, so it needs an equally careful assessment.

Risks

Side effects and rare serious risks, including vascular occlusion

Common effects are swelling, tenderness, redness and bruising for several days, and a firm feel in the treated area while the gel settles. Lumps are discussed above. Infection is uncommon but possible with any injection.

The serious risk is injection into, or compression of, a blood vessel. With any filler this can cause skin damage and scarring and, rarely, loss of vision. A 2026 systematic review of visual loss after biostimulators, written by doctors in Singapore and Malaysia, found at least 11 published cases of vascular occlusion with visual impairment after CaHA, with the nasal bridge involved in the majority. With HA filler, hyaluronidase is part of the emergency treatment; with CaHA there is no dissolving agent, so management relies on recognising it at once and urgent supportive and specialist treatment, including an ophthalmologist when vision is affected.

Seek help immediately if, after any filler, the skin nearby turns pale, white, blotchy or dusky, pain keeps increasing, or your vision changes. Contact the treating clinic at once or go to an emergency department; do not wait for a routine review.

Suitability

Who CaHA tends to suit, who it does not, and alternatives

CaHA is a structural product for people who understand that it cannot be dissolved. If hollowing has appeared quickly, you have lost weight without trying, or one side of the face has changed more than the other, see a doctor about the cause before any cosmetic treatment.

Alternatives include HA filler, which is reversible; PLLA or PCL biostimulators; skin boosters for skin quality; energy-based lifting for laxity; and, for heavy sagging with excess skin, a plastic surgeon's opinion. Doing nothing, or waiting, is also a valid choice.

Before any CaHA treatment, it is reasonable to ask the doctor which product and dilution will be used, how much in total, in which layer, and what the plan would be if a lump appeared. Keep a written record of what was injected and when. That record makes any later assessment, by the same doctor or another, far simpler and safer.

• Often discussed: volume and support in the mid and lower face and jawline in people with adequate skin thickness; the backs of the hands; diluted or hyperdilute use for crepey skin on the neck, arms or body.
• Generally avoided: the lips, the tear trough and other areas around the eyes, superficial placement in thin skin, and anyone whose priority is being able to reverse the result.
• Not advised: pregnancy or breastfeeding, active skin infection or inflammation in the area, or allergy to any component, including lidocaine for the premixed version.
• Discuss first: autoimmune disease, a tendency to keloid scars, blood thinners or a bleeding problem, recent dental infection, and any earlier filler or permanent implant in the same area.

At SkinRev Lab

Radiesse in Singapore: what happens at SkinRev Lab

Consultations are with Dr Sin Yong at SkinRev Lab, #B1-28 CityLink Mall, 1 Raffles Link, linked underground to City Hall and Esplanade MRT, open daily 11am to 8pm (WhatsApp +65 8266 9585), or at IN Eternity Clinic, 9 Scotts Road, #12-01 Pacific Plaza, beside Orchard MRT, Monday to Saturday 11am to 8pm (WhatsApp SkinRev Lab on +65 8266 9585 or IN Eternity Clinic on +65 8815 3008).

Our treatment pages list HA fillers and PLLA and PCL collagen biostimulators among the injectables Dr Sin Yong performs; ask which product would be used and why. If you have had CaHA elsewhere and are concerned about a lump, overcorrection or a heavy look, he takes a history of what was injected, when and where, examines the area at rest and in motion, and uses ultrasound to see where earlier material sits before suggesting anything. Options can include waiting, managing a nodule, a non-surgical correction plan, referral to a plastic surgeon, or no treatment. Treatment is priced at consultation.

If you think something is wrong after any filler, such as colour change, increasing pain or a change in vision, do not wait for an appointment: contact the clinic that treated you or go to an emergency department straight away.

Sources

References & sources

1. Lorenc ZP, Black JM, Cheung JS, et al. Skin tightening with hyperdilute CaHA: dilution practices and practical guidance for clinical practice. Aesthet Surg J. 2022;42(1):NP29-NP37. PMID 34192299.
2. Emer J, Sundaram H. Aesthetic applications of calcium hydroxylapatite volumizing filler: an evidence-based review and discussion of current concepts (part 1 of 2). J Drugs Dermatol. 2013;12(12):1345-1354. PMID 24301235.
3. Bass LS, Smith S, Busso M, McClaren M. Calcium hydroxylapatite (Radiesse) for treatment of nasolabial folds: long-term safety and efficacy results. Aesthet Surg J. 2010;30(2):235-238. PMID 20442101.
4. Kadouch JA. Calcium hydroxylapatite: a review on safety and complications. J Cosmet Dermatol. 2017;16(2):152-161. PMID 28247924.
5. Tzikas TL. A 52-month summary of results using calcium hydroxylapatite for facial soft tissue augmentation. Dermatol Surg. 2008;34(Suppl 1):S9-S15. PMID 18547188.
6. Yankova M, Pavicic T, Frank K, et al. Intraarterial degradation of calcium hydroxylapatite using sodium thiosulfate: an in vitro and cadaveric study. Aesthet Surg J. 2021;41(5):NP226-NP236. PMID 33544840.
7. Danysz W, Nowag B, Hengl T, et al. Can sodium thiosulfate act as a reversal agent for calcium hydroxylapatite filler? Results of a preclinical study. Clin Cosmet Investig Dermatol. 2020;13:1059-1073. PMID 33408497.
8. Young SM, Goh ASC, Jeyabal P, Ooi ASH. Visual loss in biostimulator injectables: a review of incidence, risk factors, etiology and management proposal. Aesthetic Plast Surg. 2026;50(5):1994-2005. PMID 41263987.

Common questions

Your questions,
answered