A study by Evans and colleagues sought to ascertain the effects of supplementing with 100 mg of 5-Hydroxytryptophan (5-HTP) daily on measures of body composition in men and women who had undergone exercise training. An eight-week treatment period was used to measure body composition using a multi-frequency InBody® 270 bioelectrical impedance device. The subjects were told not to alter their exercise or eating routines, and they were also told to use a smartphone app to track their food two to three days a week. The study showed that between groups there were no differences in the amount of food consumed (i.e., total energy intake or grams of macronutrients). Fat mass considerably decreased in the 5-HTP group, while it did not alter in the placebo group. Based on this study, a daily 5-HTP intake may have an impact on body composition, with a decrease in fat mass.

Evans C, Mekhail V, Curtis J, Czartoryski P, Kaminski J, Ellerbroek A, Bustillo E, Jiannine L, Santana JC, Antonio J. The Effects of 5-HTP on Body Composition: An 8-Week Preliminary RCT. J Diet Suppl. 2022 May 18:1-10. doi: 10.1080/19390211.2022.2076760. Epub ahead of print. PMID: 35583055.