Why does hair fall out so easily and often?

What could be the causes for hair to fall out very easily if you're male, 20, and average weight + height?

• this has been going on for years. i have thick hair and up close or from afar you wouldn't be able to tell i have this problem. No one else in my family does has this. it seems like a strand of hair from here and there (everywhere) falls out on its own, but more comes out if i comb my hair. i don't think if i played with my hair or combed it all day i'd have a bald spot, but plenty of hair falls out anyway. What could be wrong with me?

• Answer:

  You're a young man, so high-Testosterone, and usually that means you produce a lot of hair, if it isn't thinning, it's just your hair-cycle. Nothing wrong, just nature.