['Previous studies have demonstrated that sun-induced alteration of epidermal permeability barrier function varies with gender and age. In the present study, we assess the stratum corneum (SC) hydration in sun-exposed males and females.', 'A total of 168 subjects (84 males and 84 females) aged 19-75 years were enrolled. A multifunctional skin physiology monitor was used to measure SC hydration.', 'In comparison with non-sun exposure, sun exposure does not cause a significant change in SC hydration in either young males or young females, whereas in aged females, a significant reduction of SC hydration is seen on the forehead and the dorsal hand of sun-exposed subjects. SC hydration on the canthus of both aged males and aged females is significantly lower than that of young subjects. Additionally, SC hydration on the dorsal hand of aged females is also significantly lower as compared with young females. Sun-induced reduction of SC hydration is more evident on the dorsal hand of aged females than that of males (P<0.001). Moreover, the SC rehydration capacity is significantly lower in sun-exposed aged females than in age-matched males.'] Do sun-induced changes of stratum corneum hydration vary with age and gender in a normal Chinese population?