from the manfacturer’s website:

RADIESSE® Volumizing Filler Mechanism of Action

RADIESSE is comprised of Calcium Hydroxylapatite (CaHA) microspheres suspended in an aqueous gel carrier.1

RADIESSE® Volumizing Filler Mechanism of Action

Once injected, it provides immediate volume and correction but continues to work by stimulating the body to produce its own natural collagen.1

RADIESSE® Volumizing Filler Mechanism of Action

Over time, the gel is absorbed and the body metabolizes the CaHA microspheres leaving behind only your own natural collagen.1