HI, I can understand your concern for the less hair on scalp region with hair fall. The scalp hair are basically genetically mediated so it depends on family pattern.You can take vitamins in the form of biotin, calicium pantothenate and other vitamin B complexes. Multivitamin tablets contains all these essential nutrients so you can take it. Additionally increase you protein intake on daily basis and eat sprouts. Eat a lot of green leafy vegetables and sprouts which contains vitamins and minerals necessary for normal hair function. Minoxidil is helpful but should always be applied under dermatological supervision other wise can cause irritation on the scalp. Do not have guilt regarding masturbation as it is completly and totally normal process and there is no correlation of it with hair fall. You should consult a dermatologist and take guidance so that long term use can be maintained. Take care.