Hyperdilute Radiesse: Skin Tightening With a Biostimulator

Radiesse is an injectable implant whose principal component is synthetic calcium hydroxylapatite (CaHA): in the 1.5 mL syringe, particles of 25 to 45 microns suspended in a gel carrier of sterile water, glycerin and sodium carboxymethylcellulose, according to the product's instructions for use.

Injected undiluted, it adds volume: Merz says it provides immediate volume correction.

Radiesse's FDA-approved uses include moderate to severe facial wrinkles and folds such as nasolabial folds (2006), facial fat loss in people with HIV, volume loss in the back of the hands (2015), and jawline contour as Radiesse (+) (2021).

"Hyperdiluted" is a different preparation.

Merz describes it as Radiesse mixed with a higher volume of sterile saline in a 1:2 ratio, so the product can be spread more thinly across larger areas — used, in Merz's words, specifically for the décolleté (chest) to address fine lines and "crepey" skin texture.

The technique was described in 2018 consensus guidelines, in which an expert panel described CaHA diluted 1:1 or hyperdiluted to 1:2 and beyond as stimulating neocollagenesis — new collagen — in the injection area to improve laxity and skin quality.

The panel's own name for this: a "novel off-label use."

One diluted use has since moved onto the label: on March 31, 2026, FDA approved Radiesse diluted 1:2 with 0.9% sterile saline, injected subdermally, for décolleté wrinkles in patients 22 and older.

The chest is the one approved area: the 1:2 mix, injected subdermally with a 22-gauge flexible cannula, for décolleté wrinkles in patients 22 and older.

The neck has no such line in the label — Radiesse carries no neck approval, diluted or undiluted, so the technique there is off-label.

So are the arms, thighs, abdomen, knees and buttocks.

• Chest (décolleté) — approved, diluted 1:2, cannula, adults 22 and older.
• Neck — off-label; the 2018 consensus guidelines describe it as exactly that.
• Upper arms, abdomen, upper legs (thighs), buttocks — off-label, same consensus paper.
• Cheeks and mid-face — undiluted Radiesse is not approved for cheek augmentation; diluted use in the face appears in the consensus paper, also as off-label.

What off-label means here: the use does not appear on Radiesse's FDA label — the label's list of approved indications has no entry for it.

The 2018 consensus panel that mapped the technique across these areas listed bruising, swelling, mild pain and induration as adverse events, and Merz lists bruising, redness, swelling, pain and itching among common Radiesse side effects.

Two practical notes: Radiesse particles are radiopaque — visible on X-rays and CT scans — so patients are told to tell health care providers and radiologists they have had it, and in the maker's décolleté imaging sub-study, no diluted Radiesse was seen on mammograms or breast ultrasounds.

The regimen studied for the chest was 3 treatment sessions — day 1, week 6 and week 12, with an optional retreatment at week 36.

Each session in the 152-subject study used 1.5 mL of Radiesse diluted with 3.0 mL of saline and injected through a cannula.

Cost follows the session count and the syringes.

Radiesse has more than one approved fill: FDA supplements have approved 0.3 cc, 0.8 cc, 1.3 cc and 3.0 cc syringes, and the current instructions describe a 1.5 mL syringe — the size the décolleté study used, one per session. "A syringe of Radiesse" is therefore not a fixed amount, and per-syringe quotes are only comparable when the fill size is stated.

As for the number itself: we could not find a published per-session or per-syringe price for hyperdilute Radiesse from Radiesse's maker or from ASPS as of October 20, 2026.

What a quote turns on is the plan — how many sessions are scheduled and how many syringes of which fill size each takes — so ask what a quote includes.

The décolleté study followed 152 subjects at 9 US sites for 84 weeks.

At week 24, 71.2% of treated subjects were responders, against 6.3% of untreated controls, and 60.7% of the treated group were still responders at 60 weeks.

Those percentages are trial results from one study — not a prediction for any individual.

On duration, Merz says Radiesse results have been shown to remain for up to 2 years, a maker figure for the product in general citing a 2010 study.

Merz's own safety information is more bounded: it says it is not known whether Radiesse is safe or effective beyond 84 weeks in the décolleté.

For what results look like area by area — including what the chest trial measured — the Radiesse before and after page has the breakdown.

Both are marketed as "biostimulators": injectables whose makers say they stimulate collagen production.

The materials differ — Radiesse is calcium hydroxylapatite, while Sculptra is poly-L-lactic acid, made by Galderma.

The two labels differ, too.

Diluted Radiesse has exactly one approved use: chest wrinkles.

Sculptra is indicated for shallow to deep nasolabial fold contour deficiencies and other facial wrinkles, for fine lines and wrinkles in the cheek region, and for HIV-related facial fat loss — its label gives it no body indication at all.

On duration, both makers publish "up to" figures: Merz puts Radiesse results at up to 2 years, citing a 2010 study, and Galderma says Sculptra results can appear as early as 1 month with a stated duration of up to 2 years.

Both are maker maximums, not guarantees.

One difference worth knowing before either: hyaluronidase, the enzyme that breaks down hyaluronic acid filler, does not work on Radiesse — Cleveland Clinic notes it dissolves only hyaluronic acid fillers, not other materials, and Radiesse is calcium hydroxylapatite.

For the undiluted products side by side — approved areas, cost structure, side effects — the Radiesse vs Sculptra comparison goes deep, and the Radiesse guide covers all five approved uses in full.