Greetings! Firstly lets understand that its common for a boy (of your age) to masturbate but its important to understand that anything done in excess is harmful. The best way to judge what is the appropriate limit - is that you must satisfy yourself only when your are actually aroused, rather than looking to be aroused every now and then; also the limit is appropriate if the thought of masturbation is not keeping you preoccupied from your daily normal academic/professional and social activities. I hope I have been clear in my explanation. I understand that this is not a commonly discussed topic in our country and I do understand that all teenagers need adequate sex-education. If needed - there's nothing wrong in seeing a counsellor/psychologist/psychiatrist. About hair fall - all men secrete testosterone and dht - and this causes hairfall - or rather- hair miniaturisation - in susceptible individuals - esp those with family history of hairfall/thinning/balding. There's no scientific evidence to say that masturbation causes hairfall. PS - Do not forget - anything in excess is harmful. Hope this answers your queries. For further queries - I can be contacted on follow up messaging / practo direct consult. Warm regards, Dr Govind Suresh Mittal. Bengaluru.