Alleviating UV-induced photoaging with oral hyaluronic acid: insights from a hairless mouse model

Hyaluronic acid (HA) is known for its beneficial effects on skin hydration and elasticity. However, the mechanisms by which HA dietary intake attenuates pathological processes in photoaged skin are still unclear. In this study, oral administration of HA, alone or in combination with hydrolysed collagen, was investigated to alleviate UV-induced inflammation, extracellular matrix (ECM) degradation, and metabolic alterations in the skin of SKH-1 hairless mice repeatedly exposed to UVA and UVB radiation. Both supplements reduced UV-induced degradation of HA and collagen and decreased the inflammatory response in the skin. Interestingly, HA supplementation influenced cutaneous and plasma metabolism, elevating lipid catabolism and metabolic markers such as hydroxybutyrate and a-ketoglutarate. The addition of collagen did not provide any additional significant benefits over HA despite being administered at a 12-fold higher dose. These findings highlight superior role of HA as a nutritional supplement for skin health and provide insights into its potential mechanisms in addressing photoaged skin by modulating both skin and systemic metabolism.