I had some good results a few years ago when combing it with L tyrosine.
Ive read articles and things online that swear it must be used with tyrosine in order to work longterm. theres a really interesting site i cant recall the name now but it goes into a huge detailed scientific explanation but what it boils down to is the 2 (5htp and tyrosine) balance each other out, too much of one overpowers the other and vice versa. so at one point i tried a relatively high dose of both, tyrosine empty stomach in the am, and 5htp at bedtime, and i was feeling super energetic and great for a while. then i ran out and decided to stop for whatever reason. I was doing probably 200-300 mg 5htp and about 3 grams of tyrosine. (i had read about a depression study which said the patients were given several grams of tyrosine daily) i may try this again soon. im very depressed now!!