Skin ageing remains a major cosmetic concern as it is associated with extensive changes in skin function and structure. The basic science of skin ageing is now widely studied and remains anchored around nine fundamental hallmarks of ageing defined in 2013. 

Skin photoaging causes extensive functional and cosmetic changes. The classic hallmarks of systemic ageing explain the process of these changes on a molecular level. There remains a uniquely prominent role of oxidative damage and the extracellular matrix in photoaging.

UV radiation generates ROS that induces primary changes in the nuclear genome, mitochondrial genome, epigenome and cell protein population, which further lead to antagonistic changes in cell function, impaired mitochondrial function, deregulated nutrient sensing and cellular senescence. These Antagonistic changes cause altered cellular signalling and stem cell exhaustion particularly increased low-level NF-kB inflammatory signaling and decreased growth factor signaling, further increased by the alterations in the ECM. 

The current effective treatments for photoaging focus on the mitigation of ROS-associated damage through antioxidant supplementation and restoration of the intracellular signaling environment.