100 mg a day.
i've heard 5-15 g at bedtime of L tryptophan be recommended for sleep aid. the ratio of l tryptophan : 5HTP is 5:1. so 15 g l tryptophan is 3 grams 5HTP.
of course i got high on dextromethorphan too. 2 serotonin increasing drugs + instant stopping of 5htp = serotonin syndrome