Hexapeptide-9 is a synthetic six-amino-acid peptide built from repeating sequences found in collagen, used as a cosmetic ingredient. Published research is thin; the main peer-reviewed human study tested a cyclized (modified) version.
Hexapeptide-9 is classed as a matrikine: a short peptide resembling fragments released when collagen breaks down, which reviews describe as signals that can influence extracellular-matrix turnover [2][3]. This mechanism is proposed for the ingredient class rather than demonstrated for hexapeptide-9 specifically. The 2025 trial authors reported internal data that a cyclized form resisted collagenase digestion (>95% intact after 24 h) while the linear form was fully hydrolyzed [1].
| Study | Model | Reported result | Source |
|---|---|---|---|
| Cyclized hexapeptide-9 vs retinol [1] | Human Adults 30-55, randomized, double-blind, vehicle- and active-controlled (n=96), 56 days | Primary endpoint: number, area and roughness of crow's feet and forehead lines (imaging). Secondary: elasticity, firmness, pigmentation, barrier. Published. | Peer-reviewed J Cosmet Dermatol 2025 |
| Collagen I/IV fragments review [2] | Review Review of collagen-derived peptide fragments | Summarizes biological activities reported for collagen I and IV fragments in tissue models. | Peer-reviewed Life Sci 2019 |
| Matrikines in tissue remodelling [3] | Review Review of matrix-derived signaling peptides | Describes how matrix-derived peptides act as signals in tissue remodelling; context for collagen-fragment cosmetic peptides. | Peer-reviewed Adv Drug Deliv Rev 2022 |
Human cosmetic studies describe appearance only. Lab results do not establish effects on skin structure.
