The first day I started taking taking "l-tyrosine with vitamin C and b6". I've been struggling to get it back trying all sorts of Test boosters thinking it was hormonal, but maybe it was chemically all along. But c'mon I'm 21 so my testosterone can't be low. My Total test levels were in the uppers normal range last month. So they say dopamine plays a role in libido and so does test. So any of you looking for an additional libido boost try L-tyrosine; it also gives you more energy, increases metabolism, and it's and alternative to caffeine, so it's girth friendly unlike caffeine.