Calcium Hydroxylapatite for Facial Rejuvenation: Properties, Mechanisms, and Clinical Applications.

Calcium hydroxylapatite (CaHA) has evolved from hard tissue applications to become a prospective bioactive filler for facial rejuvenation, offering both immediate volumization and long-term regenerative benefits. This review synthesizes literature up to 2025 to summarize the material properties, mechanisms of action, and clinical applications of CaHA-based fillers, evaluating their safety and efficacy. CaHA-based fillers provide structural support and stimulate collagen synthesis by activating fibroblasts, leading to sustained improvements in skin quality, volume restoration, and contour enhancement. Clinical evidence confirms the effectiveness of both pure CaHA and composite formulations combining CaHA with hyaluronic acid, which integrate rapid correction with prolonged regeneration. However, risks such as nodule formation, technical challenges, and the absence of reversal agents require consideration. CaHA-based fillers represent a significant advancement in minimally invasive facial rejuvenation by merging mechanical support with biological regeneration. Future research should focus on optimizing particle design, standardizing injection protocols, and developing multifunctional carriers to enhance safety and predictability.Impact StatementAs a traditional material for bone and dental repair, calcium hydroxylapatite (CaHA) has surprisingly emerged as a bioactive soft-tissue filler for facial rejuvenation. This review clarifies why this inorganic material can stimulate collagen, restore volume, and improve skin quality, bridging its regenerative mechanisms with clinical practice. By summarizing current applications, efficacy evidence, and safety considerations, we aim to enhance professional understanding, promote wider adoption, and inspire further translational research in minimally invasive aesthetic medicine.