DCLASSY CaHA: the collagen stimulator you cannot take back

Calcium hydroxylapatite belongs to the same mineral family as human bone and tooth. This is not an exotic chemical; it is a material the body already recognises, formed into microscopic spheres and suspended in gel.

What happens in the skin unfolds in three stages.

Stage 1 — what the gel does immediately

The carrier gel occupies space at the injection site. At this point the effect resembles a filler. It is temporary.

Stage 2 — the gel is absorbed

Over some weeks the carrier gel is resorbed, and part of the initial fullness goes with it. This is the stage patients most often read as failure, when in fact it is the point at which the real mechanism begins.

Stage 3 — what the microspheres do

After the gel has gone, the CaHA microspheres remain. Cells are recruited around those particles, and new collagen is laid down in the process. Histological studies describe type III collagen rising first and type I increasing later. The microspheres themselves biodegrade gradually over one to two years.

To be accurate about the limits of this account: the precise pathway has not been fully established. A foreign-body response to the particles and signalling by calcium ions have both been proposed, and reviews of the field state plainly that the supporting evidence remains incomplete.

This is the most important section on the page, and it belongs before anything else.

A hyaluronic acid filler can be dissolved. If the result is unsatisfactory, or something goes wrong, hyaluronidase removes it. That reversibility is a large part of why HA fillers are used as widely as they are.

CaHA has no equivalent. Hyaluronidase does not dissolve it. Sodium thiosulfate has been proposed as an alternative, but later work found no dissolution effect and no advantage over saline. The measures used when a nodule appears — saline injection with massage, intralesional treatment, laser, and ultimately surgical removal — disperse or extract the material; they do not dissolve it.

Which makes the operating principles straightforward.

• Do not overcorrect. Too little can be added to later; too much cannot be taken back
• Do not place it superficially. Superficial placement is the commonest reason a nodule becomes visible
• Avoid the sites where nodules cluster. We do not treat lips or the tear trough with CaHA
• Do not try to finish in one sitting. Build in stages and review

Being conservative here is not timidity; with this material it is simply correct practice. The microspheres do biodegrade over one to two years, so time eventually resolves most things — but it is better not to spend that time unhappy.

Miso Clinic stocks two CaHA products, DCLASSY and Radiesse. Both are CaHA microspheres in gel, and we select between them by site and objective.

On the evidence, precision matters. Most of the clinical literature on CaHA concerns Radiesse. Radiesse received FDA approval for facial wrinkles in 2006, for dorsal hand volume loss in 2015, and for décolleté wrinkles in 2026. The mechanism and histological findings described on this page come from that body of work.

DCLASSY is a separate product. It holds a Korean MFDS licence as a tissue-repair material, but Radiesse's clinical data do not transfer to it automatically. No published comparison of the two products' microsphere concentration or gel composition exists, so there is no basis on which to call either superior. We stock both to have a choice, not because one outranks the other.

All six products the clinic stocks are described as improving the skin. What happens in the tissue differs in each case.

GOURI and DCLASSY both stimulate collagen, but the stimulus differs. GOURI is particle-free liquid that spreads and works on skin quality; DCLASSY leaves particles in place that act more strongly at the site and provide some volume as well. So: texture points toward GOURI, while firmness combined with gentle hollowing points toward DCLASSY.

Six collagen boosters compared — which one fits →

Reasonable candidates

• Thinning skin combined with a clear loss of firmness
• Gentle hollowing of the cheeks or temples that casts shadow
• Patients who want to see some change straight away rather than only over months
• Patients who have had several skin boosters without enough change in firmness
• A preference for longer-lasting results

Where CaHA is the wrong choice

• Lips — safety not established and nodules reported; we do not treat lips with CaHA
• Tear trough — a site where nodules cluster; we approach this area differently
• Pigmentation, redness, pore size, acne scarring — not what CaHA treats
• Deep dynamic lines — botulinum toxin territory
• Precise contour sculpting — irreversibility makes fine adjustment unwise. HA filler is the right tool
• Pregnancy or breastfeeding, under 18, active infection at the site, bleeding disorders, history of severe allergy, autoimmune or granulomatous disease

Among collagen stimulators, CaHA has one of the stronger regulatory and clinical records. The U.S. FDA approved CaHA for facial wrinkles and HIV-associated facial lipoatrophy in 2006, for dorsal hand volume loss in 2015, and for décolleté wrinkles in 2026 — the last on the basis of a multicentre randomised study of 152 patients followed to 84 weeks.

Findings at tissue level have also been reproduced. Treated sites show increases in type I and type III collagen and in elastin, and comparison against hyaluronic acid filler found higher collagen staining at nine months on the CaHA side.

Two qualifications belong alongside that. First, this evidence concerns Radiesse; no clinical trial data specific to DCLASSY is publicly available. Second, a 2024 systematic review of the CaHA literature found that the controlled studies carry risk of bias and vary enough between themselves that pooled analysis was not possible.

A fair summary: that CaHA as a material increases collagen is reasonably well supported at the class level; the performance of any individual product is not something that can be promised in numbers.

The consultation begins by separating hollowing from loss of firmness. If DCLASSY is appropriate, site, volume and depth follow — and because the material cannot be reversed, we spend longer on this step than we would otherwise.

Topical anaesthetic is applied, then the product is placed by cannula or needle into the deep dermis or subdermal plane, depending on site. Placing it superficially is avoided as a matter of principle, and volume is distributed rather than deposited in one spot.

The area is smoothed afterwards. Immediately post-treatment the gel makes the result look slightly fuller than it will finally be; that settles over some weeks. We account for this by deliberately placing less at the outset.

Swelling and bruising can last somewhat longer than with other boosters. Allow at least a week before anything important.

• Do not press or rub the treated area yourself — product can be displaced
• Avoid sauna, jjimjilbang, strenuous exercise and alcohol on the day
• Use sun protection diligently
• If something palpable remains, or one side stands proud, come back rather than waiting — early management is easier

This reference was written and reviewed by Dr. Lee Chi-Hak, director of Miso Clinic in Daegu, South Korea. The clinic stocks six collagen boosters and skin boosters with genuinely different active materials — liquid PCL (GOURI), PN (Rejuran), hADM (Re2O, CellREDM) and CaHA (Radiesse, DCLASSY) — and selects between them according to which kind of ageing the face is actually showing. A clinic holding one product will use that product. See our comparison of all six and the references on liquid PCL, polynucleotide, Re2O, CellREDM and Radiesse.