Commentary on: Skin Tightening With Hyperdilute CaHA: Dilution Practices and Practical Guidance for Clinical Practice.

Abstract

Since 2006 calcium hydroxylapatite (CaHA; Radiesse, Merz North America, Raleigh, NC) has been approved by the FDA for correction of facial wrinkles and folds, for human immunodeficiency virus–associated facial wasting, and, since 2015, for hand augmentation. The commercial product is composed of approximately 30% CaHA and 70% carrier gel, providing a dual effect—filling/volumizing tissue and biostimulating the tissue’s own fibroblasts. Nondiluted product is characterized by high viscoelastic properties and is therefore particularly suited to lifting and revolumizing aging soft tissue in the midface. The current FDA-approved mixing protocol produces a final lidocaine concentration of 0.3%. Although not yet FDA-approved, dilute (1:1) and hyperdilute (1:2 and higher) CaHA have become widely used for skin tightening as a novel technique that takes advantage of the biostimulatory properties of CaHA.1 The first studies used hyperdilute CaHA in the neck and décolletage to improve the mechanical properties of skin and stimulate neocollagenesis. Several histologic studies have shown that CaHA stimulates neocollagenesis, neoelastogenesis, angiogenesis, and fibroblast proliferation, thereby significantly reducing skin laxity and improving contours and firmness in individuals with age-associated skin changes—effecting these changes without producing any volumizing effect.2