They are supposed to. I wasn't very consistent about using them once my hair started coming back in so I'm not the one to ask. I found out which ones to use by doing a web search on *hair loss diet*. I was taking several vitamins but I think it's the biotin that worked the best. One thing I did learn, one vitamin when taken in too large a dose can actually cause more head hair loss. It was either e or a. And when you buy "hair vitamins" they usually have too high a dose of it so be careful.