Skin Mediates the Aphrodisiac Effect of UVB Light Via a Skin-Brain-Gonad Axis

Ultraviolet (UV) light affects endocrinological and behavioral aspects of human sexuality via an unknown mechanism. Using a unique male-female comparative approach, we discovered that the sexual behavioral and hormonal features enhanced by UVB are mediated by the skin. In mice, UV exposure increases hypothalamus-pituitary-gonadal axis hormone levels, resulting in enhanced ovary size, extended estrus days, and anti-Mullerian hormone (AMH) expression. It likewise enhances sexual responsiveness and attractiveness of females and heterosexual interactions of both males and females. Conditional knockout of p53 specifically in skin keratinocytes abolished UV’s effects. In humans, UV exposure enhanced romantic passion in both genders, increased testosterone levels in men and correlated with heightened plasma AMH levels in women. Our data, revealing that UVB triggers a skin-brain-gonadal axis through skin p53 activation, offers therapeutic opportunities for sex-steroid-related dysfunctions. We speculate that during human furless skin evolution, the skin became the front-line regulator of the response to UVB.