Abstract: Skin photoaging is a ultraviolet radiation-induced, multi-pathway dysregulation process, driven primarily by heightened oxidative stress, chronic inflammatory activation, and disruption of extracellular matrix (ECM) metabolism. Collagen peptides (CP) mitigate photoaging by scavenging reactive oxygen species, enhancing endogenous antioxidant enzyme activities, suppressing MAPK- and NF-κB-mediated inflammatory signalling, and modulating the balance between matrix metalloproteinases and their inhibitors, thereby attenuating collagen degradation and promoting ECM remodelling. Findings from animal and in vitro studies are largely concordant, and multiple randomized double-blind clinical trials further demonstrate that oral CP improves skin hydration and elasticity and reduces wrinkles, with a favourable safety profile. Specific low-molecular-weight peptide fractions enriched in proline and hydroxyproline are regarded as the key bioactive forms. Future studies should elucidate the in vivo targets and structure-function relationships of CP and confirm its anti-photoaging efficacy in long-term clinical investigations, thereby supporting its standardized application in skin health.