Pre-melanosomes mature and differentiate into eumelanin-contained eumelanosomes and pheomelanin-contained pheomelanosomes, both of which can undergo aberrant structural changes in the presence of UV or ROS, leading to leaking of melanosomal contents (melanins, melanin synthesis intermediates, amyloids, etc) which can further react with ROS and become more toxic. Eumelanosomes may generate more amyloids and less ROS as compared to pheomelanosomes.