What is the cause of vaginal blackening?

Vaginal blackness is actually not described correctly. It should be lip black, which can be divided into lip black and lip black. The main cause of black lips is black pigmentation. Melanin is related to age, sex life, drugs and heredity. In the same situation, the older you get, the darker your labia, the more frequent your sexual life, the darker your labia, the more frequently you masturbate, and the darker your labia. In addition, it is also related to certain drugs, such as pudendum.