My hair has thinned, but I think it had more to do with the allergic reaction to hair color than anything else. 5 years after I started coloring my hair, all of a sudden I had a horrible reaction and lost a lot of hair! Considered Rogaine for women, but of all things, the side effect was weight gain!!! Haven't considered trying anything else, although there is an "all natural" product out there that, for the life of me, I can't remember the name of right now. Supposedly, no side effects, but works just as well according to the reviews.