Serotonin is a major natural appetite suppressant. It causes a feeling of satiety and loss of interest in eating. Administration of 5-HTP presumably acting as a precursor to serotonin has produced weight loss in controlled studies that were conducted in Italy in the early 90’s. Massive doses (up to nearly 500 mg) were given daily in these studies and side effects such as nausea and vomiting were experienced. Similar results with fewer side effects can be obtained with much lower doses of 5-HTP (50 mg per day). 50 mg taken 20 minutes before meals, will produce more pronounced appetite suppressant effects.
50 mg should be taken before bedtime. 5-HTP increases melatonin concentration in the brain, which induces sleep. It appears that, if 5-HTP is taken, during the day, the melatonin is stored in the pineal gland, until nightfall, when the melatonin is released by action of the biological clock. Thus, 5-HTP does not normally cause drowsiness during the day.
The mode of action of many anti-depressants is based on increasing serotonin levels in the brain. The best-known synthetic drug whose mode of action is based on serotonin increase is Prozac. Others are Paxil, Zoloft and Effexor. The advantage of 5-HTP is that it is naturally occurring (produced by the human body) and does not appear to cause impotence, as occurs frequently with synthetic serotonin elevators. It appears that in addition to an increase of serotonin, 5-HTP also causes an increase in endorphins, which are also mood enhancers.
5-hydroxy-L-tryptophan (5-HTP) is derived from L-tryptophan and is converted in the body into 5-hydroxy-L-tryptamine (serotonin), which itself is a precursor of melatonin (N-acetyl-5-methoxy-L-tryptamine). 5-HTP thus is a precursor source both of serotonin and melatonin. Therefore administration of 5-HTP can be expected to produce effects of both serotonin and melatonin. Serotonin acts as an anti-depressant and anxiolytic, a sleep restorer, and appetite suppressant.
It is also available commercially in its racemic mixture (50:50 mixture of the D and L forms), which has about ½ the activity of the natural L sterioisomer.