5-HTP, an article warning on it's use, by WebMD

http://www.webmd.com...dientname=5-htp

5-HTP (5-Hydroxytryptophan) is a chemical by-product of the protein building block L-tryptophan. It is also produced commercially from the seeds of an African plant (Griffonia simplicifolia).

Don’t use 5-HTP until more is known. 5-HTP might be UNSAFE. Some people who have taken it have come down with eosinophilia-myalgia syndrome (EMS), a serious condition involving extreme muscle tenderness (myalgia) and blood abnormalities (eosinophilia). Some people think the EMS might be caused by an accidental ingredient (contaminant) in some 5-HTP products. But there is not enough scientific evidence to know if EMS is caused by 5-HTP, a contaminant, or some other factor. Until more is known, avoid taking 5-HTP.

5-HTP is used for sleep disorders, depression, anxiety, migraine and tension-typeheadaches, fibromyalgia, binge eating associated with obesity, premenstrual syndrome (PMS), premenstrual dysphoric disorder (PMDD), attention deficit-hyperactivity disorder (ADHD), and along with prescription drugs to treat seizuredisorder and Parkinson's disease.
How does it work?
5-HTP works in the brain and central nervous system by increasing the production of the chemical serotonin. Serotonin can affect sleep, appetite, temperature, sexual behavior, and pain sensation. Since 5-HTP increases the synthesis of serotonin, it is used for several diseases where serotonin is believed to play an important role including depression, insomnia, obesity, and many other conditions.