Evolutionary theories suggest that women prefer masculine facial features in men because facial masculinity is an honest signal of men’s immune function. From a life-history perspective, masculinity signals immune function because individuals are subject to trade-offs in the allocation of limited resources (e.g. nutrition) to developing attractive traits vs maintaining health. Therefore, only healthy men can afford to divert resources to the development of masculine traits without compromising their survival. So far, studies testing the relationship between facial masculinity and immune function in men have largely been focused on current adult immunity. However, much of our facial sexual dimorphism develops during the post-pubertal adolescence period. Therefore, rather than signalling current immunity, we would expect facial masculinity to signal the ability to divert resources to facial development while maintaining the ability to fend off harmful pathogens during this critical developmental period. In this talk, using data from a longitudinal public health dataset, I will present results linking adult facial masculinity to adolescent immune function and dietary resources in men.