In some cases, hair loss can begin at the onset of puberty. Many men first notice hair loss in their 20s. Signs of hair loss include thinning hair on top of the scalp, a finer, thinner hair texture, or a receding hairline. The most common form of hair loss for men is a hereditary condition called androgenetic alopecia. Contrary to popular belief, the gene that causes androgenetic alopecia can be inherited from either your mother or your father, or from both parents. Androgenetic alopecia occurs due to a combination of heredity, hormones, and age. These factors shrink some of your hair follicles and reduce the time that they grow hair. With time, these follicles grow fewer, and finer, hairs. Eventually, they may grow no visible hair at all. Now that you know what causes hair loss, judge for yourself how Rogaine® can regrow hair.