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# Tryptophan dosage:  How much L-Tryptophan can you take?
- URL: https://www.foodconsumer.org/tryptophan_dosage_1020130639/
- Published: 2013-10-20T19:38:00.000Z
- Updated: 2026-09-22T16:21:20.000Z
- Description: In a randomized, double-blind crossover trial of 17 healthy Japanese women, doses up to 5 g a day of L-tryptophan for 21 days produced no adverse effects on food intake, body weight, or blood and urine biomarkers, the Journal of Nutrition reports.
- Author: Food Consumer
- Tags: Supplements, Nutrition, #vivvo-import

Sunday Oct 20, 2013 (foodconsumer.org) -- A new study published in Journal of Nutrition suggests that taking a daily dose of 5 grams or 5000 mg of tryptophan is safe for healthy women.

Tryptophan is the precursor to 5-hydroxytryptophan (5-HTP), which is in turn a precursor to melatonin. 5-HTP can be used to treat depression, fibromyalgia, insomnia, migraines and headaches, and obesity. Melatonin has similar functions. Therefore, it is believed that tryptophan may be converted in vivo into these active compounds and help the cited health conditions.

C. Hiratsuka from Department of Food Science and Nutrition, School of Human Cultures, The University of Shiga Prefecture in Shiga, Japan and colleagues conducted the current study and found "supplementing healthy women with up to 5.0 g/d of L-tryptophan has no adverse effects."

The randomized, double-blind, placebo-controlled, crossover intervention study included 17 healthy Japanese women aged 18-26 years with a BMI of about 20 kg/m(2). For the trial, participants were randomly assigned to receive placebo or 1.0, or 2.0, or 3.0, or 4.0, or 5.0 g/d of L-tryptophan for 21 days each with a 5-week washout period between trials. 

It was found that any dose of L-tryptophan did not affect food intake, body weight, biomarkers in the blood and urine, and amino acid composition in the blood and urine. Other evidence also suggests that taking tryptophan in a dose of up to 5 grams per day did not cause any side effects. (LD)