5-HTP (5-hydroxytryptophan) is a metabolite of the amino acid tryptophan. You may know tryptophan as the agent in turkey that makes you feel like taking a nap after Thanksgiving dinner (in addition to a full belly). 5-HTP is a direct precursor of the important inhibitory neurotransmitter serotonin, which is secreted in response to mood or emotion swings. Serotonin soothes and calms and brings about feelings of contentment.

As far back as 1975, researchers proved that giving 5-HTP to rats that were bred to overeat and be obese resulted in noteworthy reduction in food intake. Rats were fat because of a genetically determined low level of activity of the enzyme that starts the manufacture of serotonin from tryptophan. As a result, these rats never get the message to stop eating until they have taken far greater amounts of food than normal rats.

There is much incidental evidence that many humans are genetically predisposed to obesity. This predisposition may involve the same mechanism as that observed in rats genetically predisposed to obesity. In other words, many people may be predisposed to being overweight because they have a decreased conversion of tryptophan to 5-HTP and, as a result, decreased serotonin levels. By providing preformed 5-HTP, this genetic defect is bypassed and more serotonin is manufactured. 5-HTP literally turns off hunger.

The early animal studies that used 5-HTP as a weight loss aid have been followed by a series of three human clinical studies of overweight women, conducted at the University of Rome. The first study demonstrated that 5-HTP was able to decrease caloric intake and endorse weight loss regardless of the fact that the women made no conscious effort to lose weight. The average amount of weight loss during the five-week period of 5-HTP supplementation was a little more than 3 pounds.

The second study sought to determine whether 5-HTP helped overweight individuals stick to dietary recommendations. The twelve-week study was divided into two six-week periods. For the first six weeks, there were no dietary recommendations; for the second six weeks, the women were placed on a 1,200-calorie diet. The women who took the placebo lost 2.28 pounds, while the women who took the 5-HTP lost 10.34 pounds. As in the previous study, 5-HTP appeared to promote weight loss by promoting satiety-the feeling of satisfaction-leading to fewer calories being consumed at meals. Every woman who took the 5-HTP reported early satiety.

In the third study involving 5-HTP, for the first six weeks there were no dietary restrictions, and for the second six weeks the women were placed on a 1,200-calorie-per-day diet. The results from this study were even more impressive than the previous studies for several reasons. The group that received the 5-HTP had lost an average of 4.39 pounds at six weeks and an average of 11.63 pounds at 12 weeks. In comparison, the placebo group had lost an average of only 0.62 pounds at six weeks and 1.87 pounds at twelve weeks. The lack of weight loss during the second six-week period in the placebo group obviously reflects the fact that the women had difficulty adhering to the diet.

Early satiety was reported by 100 percent of the subjects during the first six-week period. During the second six-week period, even with severe caloric restriction, ninety percent of the women taking 5-HTP reported early satiety. Many of the women who received the 5-HTP (300 mg three times per day) reported mild nausea during the first six weeks of therapy. However, the symptom was never severe enough for any of the women to drop out of the study. No other side effects were reported.

There is excellent documentation that 5-HTP is an effectual antidepressant agent. One of the more impressive studies involved 99 patients described as suffering from "therapy resistant" depression. These patients had not responded to any previous therapy including all available antidepressant drugs as well as electro convulsive therapy. These therapy resistant patients were given 5-HTP at dosages averaging 200 mg daily but ranging from 50 to 600 mg per day. Complete recovery was seen in 43 of the 99 patients and significant improvement was noted in 8 more. Such major improvement in patients suffering from long-standing, unresponsive depression is quite impressive prompting the author of another study to state "5-HTP merits a place in the front of the ranks of the antidepressants instead of being used as a last resort. I have never in 20 years used an agent which: was effective so quickly; restored the patients so completely to the persons they had been and their partners had known; and was so entirely without side effects".

Migraine headaches and fibromyalgia share a common feature: both are low serotonin syndromes. After over 25 years of research, one of the lead researchers has stated "In our experience, as well as in that of other pain specialists, 5-HTP can largely improve the painful picture of primary fibromyalgia". Double-blind studies support this contention. Although a number of drugs have been shown to be useful in the prevention of migraine headaches, all of them carry significant side effects. In contrast, 5-HTP is very safe .

5-HTP may prove to be better than melatonin. Several clinical studies have shown 5-HTP to produce good results in promoting and maintaining sleep in normal subjects as well as those experiencing insomnia. One of the key benefits with 5-HTP in the treatment of insomnia is its ability to increase sleep quality.