Aesthetic Peptide Review Classifies Agents by Fibroblast Mechanisms, Delivery, and Clinical Evidence

The field of aesthetic dermatology increasingly utilizes "peptides," a broad term encompassing diverse molecules from short sequences to protein hydrolysates. This lack of precise classification leads to scientific imprecision, making it challenging to interpret efficacy and mechanism. Current applications range from topical to oral, often without clear comparative evidence. Understanding the specific molecular identity, target, and delivery route is crucial for effective use and scientific rigor in addressing skin aging and dermal repair.

This critical narrative review systematically classified peptides used in aesthetic dermatology. Researchers examined their direct or indirect relationships with dermal fibroblasts, which are central to collagen and extracellular matrix synthesis. The review integrated mechanistic insights, various delivery technologies, and available clinical evidence. It emphasized that interpretation requires considering the exact peptide sequence, chemical modification, vehicle, route, dose, and measured outcome, rather than generalizing "peptide technology."

The review classified aesthetic peptides into distinct molecular categories: chemically defined short sequences (e.g., KTTKS), lipidated derivatives, metal-binding complexes (e.g., GHK), and heterogeneous protein hydrolysates. It highlighted that longer regenerative polypeptides and growth factors are distinct from these short cosmetic peptides. Delivery technologies evaluated included topical formulations, oral supplements, dissolving microneedle patches, post-procedural regimens, and selected mesotherapy preparations. Dermal fibroblasts were identified as a key organizing center, synthesizing and organizing type I and III collagen and fibronectin. The authors noted that clinical significance is often obscured when peptides are studied with other active ingredients or devices, rather than against peptide-free comparators. > The review underscores that a shared ingredient category does not imply a shared receptor, target tissue, delivery route, or standard of evidence, necessitating precise interpretation of specific peptide characteristics.