L-Tryptophan Side Effects

L-Tryptophan is used in supplements and baby food to help sleeping and losing weight. It is commonly used as an additive for functional food products and dietary supplements. Though it’s considered safe, some are convinced it has potentially dangerous health effects.

What Is L-Tryptophan?

L-Tryptophan is an essential amino acid and a main building block of protein. Like other amino acids, L-Tryptophan is one of the building blocks of protein, but unlike some amino acids, L-Tryptophan is considered essential because the body cannot manufacture its own. L-Tryptophan plays many roles in animals and humans alike, but perhaps most importantly, it is an essential precursor to a number of neurotransmitters in the brain. As such, L-Tryptophan is the only substance normally found in the diet that can be converted into serotonin. Since serotonin, in turn, is converted in the brain into melatonin, L-Tryptophan clearly plays a role in balancing mood and sleep patterns.

Possible Side Effects of L-Tryptophan

  • Many side effects can occur with L-tryptophan, some of which are quite dangerous. For example, L-tryptophan can cause serious conditions called eosinophilia-myalgia syndrome or serotonin syndrome. Contact your healthcare provider immediately if you notice symptoms of these conditions, such as nerve pain, difficulty walking, or very severe muscle pain. Other side effects are not as serious and may include headaches, nausea, and diarrhea.

GRAS Affirmation: Yes

Generally recognized as safe (GRAS) is an American Food and Drug Administration (FDA) designation that a chemical or substance added to food is considered safe by experts, and so is exempted from the usual Federal Food, Drug, and Cosmetic Act (FFDCA) food additive tolerance requirements. L-Tryptophan is considered safe.

Suggested Dosage


Special Populations Precaution

There is a lot of concern about diet and nutrition for these population, like Newborns, children, pregnant, sensitive to L-Tryptophan populations. Better consult to your doctor if you would like to intake L-Tryptophan.


Related Research

1. Calmatives for the excitable horse: a review of L-tryptophan. [Vet J. 2005 Jul] Author: Grimmett A, Sillence MN.

2. Safety of L-tryptophan for pigs. [J Anim Sci. 1991 Jul] Author: Chung TK, Gelberg HB, Dorner JL, Baker DH.

3. Is L-tryptophan safe? [Aust N Z J Psychiatry. 1988 Dec] Author: During MJ, Freese A.

4. Enhancement of the antidepressant response to L-tryptophan by a liver pyrrolase inhibitor: a rational treatment approach. [Neuropsychobiology. 1978] Author: Shopsin B.

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