“Ultimately you’re body is going to down-regulate the enzymes needed to convert the tyrosine/l-phenylalanine into dopamine and norepinephrine; this also counts for 5 -htp being converted into serotonin. As far as I’m aware when simply supplementing amino acids to improve neurotransmitter prevalence in the brain, tolerance will build very rapidly within a one week to two week period (from personal experience). Not saying it’s not viable to help out with mood when used sparingly, just saying there’s most likely better ways for continued treatment.”
5-HTP is sold over the counter in the United States, Canada, the Netherlands, and the United Kingdom as a dietary supplement for use as an antidepressant, appetite suppressant, and sleep aid. It is also marketed in many European countries for the indication of major depression under the trade names Cincofarm, Levothym, Levotonine, Oxyfan, Telesol, Tript-OH, and Triptum.[1]