If you're young and had minor thinning, I wouldn't say your atypical Racheal, I'm 40 and my hair density double in a year as withnessed by my hairdresser (I had thick hair for a male, but now, as you see in my avatar,they are very thick except at the temples were I lost hair when I started losing hair at 18 and the regrowth has been mostly in the back end of the temples (to be expected since the frontal hair is certainly dead by now)).
Actually, what you got is more like typical, hair that's only started to miniaturize, which is what thinning is about, can regain its full size again, especially if you don't have an aggressive version of male pattern baldness; hair not very susceptible to DHT.
If you have an aggressive version, one that made you lose most hair by the time you reach 30, then even HRT may not be enough and something like dutasteride is waranted, some women, more than people think, also lose their hair.