Collagen Biostimulators: Clinical Evidence and Mechanisms of Tissue Rejuvenation

Collagen biostimulators have established themselves as essential tools in minimally invasive tissue rejuvenation due to their proven ability to induce neocollagenesis, improve skin firmness, and restore dermal architecture.This systematic review analyzed studies published between 2015 and 2024, evaluating the clinical efficacy, histological mechanisms, and safety of the main biostimulators available-poly-L-lactic acid (PLLA), calcium hydroxyapatite (CaHA), and polycaprolactone (PCL).A search of the PubMed/MEDLINE, Scopus, Web of Science, Embase, and SciELO databases identified 32 eligible studies, including clinical trials, histological analyses, and systematic reviews.The results demonstrated that all biostimulators evaluated promoted a significant increase in type I and III collagen production, improving elasticity, texture, and dermal thickness.CaHA had an immediate effect followed by a delayed stimulus, while PLLA showed progressive and highly lasting results.PCL, in turn, stood out for the longer-lasting effects, with improvements maintained for up to 30 months.The safety profile was largely favorable, with a predominance of mild and transient adverse events, such as edema and local sensitivity.Serious complications, such as granulomas and persistent nodules, were rare and usually associated with inappropriate application techniques.The discussion of the studies analyzed highlights the central role of biostimulators in modern aesthetics, especially when integrated with energy technologies or combined protocols, expanding the therapeutic potential and promoting three-dimensional rejuvenation.However, the methodological heterogeneity among the studies highlights the need for standardization of techniques, dilutions, and intervals between sessions.It is concluded that biostimulators represent effective, safe, and versatile therapies, being fundamental pillars of contemporary aesthetics and promising in personalized rejuvenation protocols.