Are you visibly becoming bald or are you just having your hair shed itself? The head sheds about 100 or so hairs a day. I was worried I was balding but after 6 years of my head doing the same thing I've concluded its just naturally doing it. Only natural thing for Hair I know is Biotin which can help strengthen hair and make it grow faster. While men's hairlines tend to naturally recede overtime as we get older, there a big difference between that and male pattern baldness which you see typically in the early to mid-twenties, and are typically completely bald on the top of their heads by 25.
You may have a vitamin deficency or you maybe drinking too much caffeine which can cause your hair to fall out also.