Radiesse® differs from other injectable materials in that it is comprised of very tiny, smooth calcium hydroxylapatite (CaHA) microspheres. The CaHA microspheres (particles) form a scaffold through which your body’s own collagen grows, and is reputed to produce a longer lasting effect. Over time, your body absorbs the gel carrier while collagen has started to grow and infiltrate the area, replacing the gel with your own, natural tissue.