This drug is basically a serotonin supplement, which soon after ingestion gets converted into this happiness hormone. It is used to treat mood related issues and depression. High levels of treatment success have been recorded when using this substance to treat depression or serotonin deficiency.
Typically, one dose of this drug is about 400mg, either once a day or split into two or more doses. For some people lower doses are very effective, although the usual user report describes this substance used in synergy with other drugs as well.
5-HTP increases stomach sensitivity, so one of the common side-effects is that you will get a "full" stomach, even if you eat just a little bit. This is why it is recommended to take it together with food. There are many 5-HTP user reviews discussing the effects. Some 5-HTP experiencies including stacking 5-HTP with other nootropics and substances.
Some combinations with 5-HTP could be lethal. Do not combine it with other antidepressant drugs or use it for cognitive enhancement without getting an approval from your doctor. It is essential to avoid combining it with SSRI's, since this is the most dangerous combination that 5-HTP has with any other drug, and it could cost you your life.