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# Tryptophan boosts serotonin in patients with depression
- URL: https://www.foodconsumer.org/tryptophan_helps_depression_0929130500/
- Published: 2013-09-29T17:59:00.000Z
- Updated: 2026-09-22T16:21:18.000Z
- Description: A 1971 Science study found tryptophan supplementation raised plasma and brain tryptophan and serotonin in rats. A 2013 Journal of Psychopharmacology study by Abdulla Badawy reports tryptophan is important in boosting brain serotonin synthesis in people with depression.
- Author: Food Consumer
- Tags: Supplements, Nutrition, #vivvo-import

Sunday Sept 29, 2013 (foodconsumer.org) -- An early study led by John D. Fernstrom and R. J. Wurtman Massachusetts Institute of Technology and published in the July 1971 issue of Science suggests that tryptophan supplementation can affect the plasma and brain tryptophan and serotonin levels in rats that received a dose of 12.5 milligrams per kilogram of body weight. Serotonin deficiency can cause sleeping problems or insomnia.

After that study, many studies have been conducted. Most recently a study released in the Oct 2013 issue of Journal of Psychopharmacology has confirmed the physiological function of tryptophan in humans. Abdulla A-B Badawy from Cardiff Metropolitan University in Cardiff, Wales, UK conducted the study and found that tryptophan, an amino acid that is the precursor to serotonin, is very important in boosting brain serotonin synthesis in people with depression.

Patients with major depressive disorder often suffer serotonin deficiency and can't sleep normally. What happens is that in depression patients glucocorticoids and/or catecholamines enhance hepatic enzyme tryptophan 2,3-dioxygenase (TDO), which in turn accelerates tryptophan degradation leading to the decreased bioavailability of tryptophan and lowering the serotonin concentration.

Tryptophan supplementation can boost the plasma and brain tryptophan levels and in turn increase the synthesis of serotonin leading to the boosting of the hormone, according to this study. In other words, tryptophan helps boost serotonin levels and improve your sleep quality.

In 2012, another study led by Sung Woo Kim and colleagues from North Carolina State University in Raleigh NC and published in Journal of Nutrition shows that large neutral amino acids including phenylalanine, tyrosine, leucine, arginine which are similar in some way to tryptophan can compete with tryptophan for the entry into the blood, that is, with high levels of large neutral amino acids, the absorption of tryptophan can be reduced. 

The study reveals that dietary L-tryptopan with reduced large neutral amino acids enhances feed efficiency and decreases stress hormone secretion in nursery pigs that face social mixing stress. In humans, the stress hormone secretion can be boosted under whatever stress, leading to reduced synthesis of serotonin in a person suffering depression, which is why depressive patients can't often sleep well. 

The study suggests that when tryptophan supplements are used, intake of other large neutral amino acids should be reduced so that tryptophan can enter the blood most efficiently. (DL)