The early animal studies that used 5- hydroxytryptophan (5-HTP) as a weight-loss aid have been followed by a series of four human clinical studies of overweight women, conducted at the University of Rome. The first study showed that 5-HTP was able to reduce caloric intake and promote weight loss despite 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 to adhere 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 an average of 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 twelve 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, 90 percent of the women taking 5-HTP reported early satiety. Many of the women who received the 5-HTP (300mg, 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.
Find out more about this book:Hunger Free Forever: The New Science of Appetite Control