I am 18 years old male and am facing severe hair loss. I do masturbate once or twice a week. What might be the possible reasons?

Probably genetic. Depending on the pattern of your hair loss, it is either genetic or caused by an underlying health problem. Masturbation will have nothing to do with hair loss. If your front hairline is receding and/or the crown is thinning, you have genetic hair loss and should visit a hair loss specialist. If you are losing all over your head, see your family doctor for tests.