Unclear. 5-hydroxytryptophan, or 5-htp, is an Amino Acid currently being sold over-the-counter in the United States. It is often marketed as a medication for the treatment of depression and as a sleep aid. While some studies have shown moderate benefits over placebo from this medication, there haven't been many high quality, well-controlled studies that found similar results.
Have not been proven. 5-htp, or 5-hydroxytryptophan, is a dietary supplement. It is a precursor to molecules that regulate mood and sleep. 5-htp is purported to be beneficial in treating depression, though its effects have not been proven in large clinical trials. 5-htp should not be combined with other anti-depressants unless supervised by a physician.