An elegant woman in her late forties, one hand resting at the base of her neck, smooth even skin on the neck and décolletage in warm window light
Radiesse Singapore · Calcium Hydroxylapatite (CaHA) · Collagen Biostimulator · Dr Sin Yong

Radiesse Singapore Calcium Hydroxylapatite, Explained

Dr Sin Yong · MBBS (NUS) · MRCS (Edin) · MSc Aesthetic Medicine (London) · MSc Practical Dermatology (Cardiff) · International KOL

Radiesse is calcium hydroxylapatite microspheres in a gel carrier. Undiluted, it fills on the day and stimulates collagen afterwards; diluted, it becomes a skin-quality treatment for the face, neck and body. Neither form is dissolvable — assessed and placed by Dr Sin Yong at Orchard Road, Singapore.

At a glance

One Product, Two Jobs

At a glance
What it is
Calcium hydroxylapatite (CaHA) microspheres suspended in an aqueous gel of sodium carboxymethylcellulose, glycerin and water, manufactured by Merz
Composition
About 30% CaHA microspheres of 25–45 µm in about 70% gel carrier. Radiesse (+) adds lidocaine
Regulatory history
US FDA approval in December 2006 for HIV-associated facial lipoatrophy and for moderate-to-severe facial folds; later approvals cover the hands and, for Radiesse (+), the jawline
Mechanism
The gel gives immediate volume; as it is absorbed, fibroblasts lay down collagen around the microspheres, which are later metabolised as calcium and phosphate
Hyperdilution
Mixed with saline and lidocaine and placed superficially across an area, it is used for skin quality rather than volume — neck, décolleté, arms, abdomen, thighs, buttocks, hands
Reversibility
Not by hyaluronidase. Intralesional sodium thiosulfate has been reported for CaHA nodules; it is a management option, not an equivalent of dissolving
Imaging
CaHA is radio-opaque and clearly visible on ultrasound, which helps when a previous injection needs to be identified
Where it does not belong
Lips, tear troughs and the glabella; and it should not be placed over unmapped previous filler
Before any top-up
An ultrasound scan of what is already in the tissue. Lumps and heaviness after earlier injections usually call for subtraction, not more
Approach used here
Undiluted only deep and in small amounts for structure; hyperdiluted in the superficial plane for skin quality; the two are planned as different procedures, not one

What Radiesse actually is

Radiesse is a suspension of calcium hydroxylapatite microspheres in a water-based gel. Calcium hydroxylapatite is the mineral that makes up bone and tooth enamel; here it is manufactured synthetically into smooth spheres between 25 and 45 microns across, which form roughly 30% of the syringe. The gel carrier — sodium carboxymethylcellulose, glycerin and water — is the other 70%.

Like Ellansé, it works in two phases. The gel provides correction on the day. As the gel is absorbed over the following weeks, fibroblasts respond to the microspheres by producing collagen around them, and that collagen carries the result once the gel has gone. The microspheres themselves are gradually broken down and metabolised.

What sets Radiesse apart from the other biostimulators is how far it has been studied in diluted form. Mixed with saline and lidocaine and placed in a thin layer close to the surface, it stops being a volumiser and becomes a treatment for skin quality across large areas — a different procedure using the same product.

Undiluted or hyperdiluted: two different procedures

The dilution decides what Radiesse is for, and the two uses should not be confused with each other.

Undiluted, or lightly diluted, it is a structural product. It is placed deep, on bone or in deep fat, in small amounts where projection or support is needed: the chin, the jawline, the pre-jowl area, the back of the hand. In this form it is firm and it is visible if placed too superficially, which is why it is kept away from thin, mobile skin.

Hyperdiluted, it is spread in a thin layer in the superficial subcutaneous plane across an area, usually with a cannula, to improve laxity and texture rather than to fill anything. A 2019 international consensus set out dilution ratios and depths for the face, neck, décolleté, arms, abdomen, thighs, buttocks and hands; the neck and the backs of the hands are among the more studied areas. The result is a change in skin firmness and quality that arrives gradually as collagen forms, not volume.

A clinic offering “Radiesse” may mean either. It is worth knowing which before you agree to anything.

The hands of a woman in her fifties resting on white linen in soft window light, a simple gold ring
Illustrative. The backs of the hands are among the more studied areas for hyperdiluted calcium hydroxylapatite; the aim is skin quality, not volume.

Radiesse is not reversed by hyaluronidase

Hyaluronidase dissolves hyaluronic acid filler and nothing else. It has no action on calcium hydroxylapatite or on the gel that carries it. A misplaced or excessive Radiesse result is managed, not erased.

There is one difference from the other biostimulators worth stating accurately. Intralesional sodium thiosulfate has been reported in the literature as a treatment for calcium hydroxylapatite nodules, with laboratory work showing it can degrade the material. It is an option for a nodule, not a way to reverse a treatment, and it is not routine. Calcium hydroxylapatite is also radio-opaque and clearly visible on ultrasound, which makes it one of the easier materials to identify when a previous injection needs to be assessed.

Problems from Radiesse placed elsewhere are assessed under filler correction, with imaging first.

“Radiesse is the one biostimulator that also fills on the day. That makes it easier to overdo, not harder.”

Dr Sin YongOn why immediate volume is a risk as much as a feature

How Dr Sin Yong uses it

Dr Sin Yong treats the two forms of Radiesse as two procedures with different plans, and does not mix them in one appointment without a reason.

For structure, he places undiluted product deep and sparingly — on the periosteum of the chin and jaw, or in the deep fat where the anatomy allows — reading the jawline as a line from chin to angle rather than as a set of points, and leaving the lower face lighter than a day-one judgement would suggest, because the collagen response adds to it later and cannot be removed.

For skin quality, he hyperdilutes according to the published consensus ranges, adjusted to the thickness of the skin in that area, and places it superficially with a cannula in a fan pattern so that the product is a thin even layer rather than a series of deposits. The neck and the backs of the hands are the commonest requests; the abdomen and inner arms after weight loss are the next. Where laxity rather than skin quality is the real complaint, he will say so and point to focused ultrasound or the 4K Body Lift instead.

Who Radiesse suits, and who it does not

Undiluted, it suits a patient who needs structural support in firm tissue — chin, jawline, lateral cheek, hands — and who wants some change on the day while choosing the product for the collagen that follows. Hyperdiluted, it suits crepey, lax skin on the neck, chest, arms, abdomen and hands in a patient who can wait for a gradual change in quality and who understands it is not a volume treatment.

It does not suit the lips, the tear troughs or the glabella, where a firm, non-dissolvable, radio-opaque material has no defensible place. It does not lift a descended plane: a jowl or a loose jawline is a laxity problem, and adding volume below it makes it heavier. And it is not the right first injectable in a face that has never been assessed; a reversible hyaluronic acid filler is the more forgiving start.

Against its neighbours: Sculptra gives almost nothing on the day and is used diffusely for deflation; Ellansé is the closest relative, immediate plus stimulating, but is less studied in diluted form. Which fits is decided by the anatomy and the goal, not by brand.

A woman in her forties in side profile, chin gently raised, showing the line of the jaw and neck
Illustrative. Undiluted product is for structure in firm tissue; a descended jowl is a laxity problem, not a volume one.

Noticed lumps or heaviness? Scan before you add

A face that has been injected more than once often arrives with a complaint that sounds like it needs more product — a heaviness in the lower face, a fullness under the eyes, a lump that has appeared months after the last visit. In Dr Sin Yong's experience the opposite is more often true: the problem is what is already there, and the answer is subtraction, not addition.

So before any further Radiesse is placed, he scans. High-frequency ultrasound shows what material is sitting in the tissue, how deep it is, whether it has migrated, and whether a lump is calcium hydroxylapatite, old hyaluronic acid filler, a cyst, or scar. Each of those is managed differently, and two of them are made worse by injecting on top. A scan takes minutes and changes the plan more often than not.

If the scan shows that less is what you need, that is a different procedure with its own planning — see filler correction. If it shows a clean field, Radiesse can be placed with confidence rather than hope. Either way, nothing is added to a face that has not been looked beneath.

Risks and what to expect of the procedure

The common findings are swelling, bruising and tenderness, and a temporary firmness where undiluted product sits. Nodules and visible or palpable product are the specific risks of a firm material placed too superficially; with hyperdiluted product the risk is more often unevenness or small nodules in thin skin. The serious risks are vascular and attend any injectable placed near facial vessels, which is why depth and anatomy matter more than the product.

Calcium hydroxylapatite is metabolised by the body over time and the collagen it produced ages with the rest of the skin. The change is not lifelong, and no duration quoted to you is a prediction for your anatomy.

Radiesse Singapore — Frequently Asked Questions

Both, in sequence. The gel carrier gives volume on the day; as it is absorbed, the calcium hydroxylapatite microspheres act as a scaffold and the skin builds collagen around them. In hyperdiluted form the volume effect is negligible and it is used purely for skin quality.
Not with hyaluronidase, which acts on hyaluronic acid only. Intralesional sodium thiosulfate has been reported for calcium hydroxylapatite nodules and can degrade the material, but it is a management option for a lump, not a way to reverse a treatment.
Radiesse mixed with saline and lidocaine, usually at ratios set out in a 2019 international consensus, and placed in a thin superficial layer across an area with a cannula. Used this way it treats skin laxity and texture on the neck, chest, arms, abdomen, thighs, buttocks and hands rather than adding volume.
Radiesse gives volume on the day and stimulates collagen afterwards; Sculptra is poly-L-lactic acid with almost no immediate volume. Radiesse is also the one more often diluted for skin quality. Neither is reversed by hyaluronidase.
Both give immediate volume and then collagen, and neither can be dissolved. Radiesse is calcium hydroxylapatite; Ellansé is polycaprolactone. Radiesse has been more extensively studied in hyperdiluted form for the body.
No. A firm, non-dissolvable, radio-opaque material has no defensible place in the tear troughs, lips or glabella, and Dr Sin Yong does not use it there. A reversible hyaluronic acid product is the appropriate choice for those areas.
Calcium hydroxylapatite is radio-opaque and can be seen on radiographs, CT and ultrasound. Tell your radiologist and dentist that you have had it. Clinically this is also useful: it makes previous Radiesse one of the easier fillers to identify.
Nodules are described with every collagen stimulator and are usually related to superficial placement or product concentrated in one spot. A lump that is growing, painful or red should be examined, usually with ultrasound, before anything is done to it.
Not by adding more. Heaviness and lumps after earlier injections are usually a sign of too much, misplaced or migrated product, and the first step is an ultrasound scan to see what is there and where. It may be subtraction you need, which is handled under filler correction, before anything new is considered.
References

de Almeida AT, Figueredo V, da Cunha ALG, et al. Consensus recommendations for the use of hyperdiluted calcium hydroxyapatite (Radiesse) as a face and body biostimulatory agent. Plastic and Reconstructive Surgery – Global Open 2019;7(3):e2160. source
US Food and Drug Administration. Radiesse® injectable implant: summary of safety and effectiveness data, P050037, December 2006. source
Robinson DM. In vitro analysis of the degradation of calcium hydroxylapatite dermal filler: a proof-of-concept study. Dermatologic Surgery 2018;44 Suppl 1:S5–S9. source
Wortsman X. Identification and complications of cosmetic fillers: sonography first. Journal of Ultrasound in Medicine 2015;34(7):1163–1172. source
Singapore Medical Council. Guidelines on Aesthetic Practices for Doctors, 2016 Edition. source

Medically reviewed by Dr Sin Yong, MBBS (NUS), MRCS (Edinburgh) · Last updated 2 October 2026

Structure or skin quality — decided first

Undiluted and hyperdiluted Radiesse are different procedures for different complaints, and neither can be dissolved. Dr Sin Yong decides which, if either, fits before anything is placed.

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