UPDATED 05/20/2016

L-Tryptophan Review
L-Tryptophan Review

PUBLISHED: 05/24/2012 by BR Publishing
Editor's Review: 3.6/5.0
Product Star Rating 10yrs or More
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L-Tryptophan is an amino-acid based formula which promotes relaxation, restful sleep, and positive mood. It acts by supporting the synthesis of the hormones melatonin and serotonin responsible for mood and stress response and for regulating the sleep-wake cycles. Other beneficial effects refer to the immune system, circulation, digestive and nervous systems and the metabolism of foods.

Even though the product has not been evaluated by the FDA, it is advertised as a natural and tested product which meets the highest quality standards. It is commercialized as 500mg Capsules, 500g Tablets and as Powder.

The manufacturer, Source Naturals, is an American Company established in 1982. The company activates in the nutritional supplements industry and is the winner of some prestigious awards due to innovative formulations such as Life Force Multiple, Mega-Kid Multiple or Inflama-Rest.

L-Tryptophan Ingredients

L-Tryptophan includes the following ingredients: L-Tryptophan, Calcium (only the Tablets), Iron (only the Tablets and Capsules), gelatin (capsule), dibasic calcium phosphate, microcrystalline cellulose, silica, and magnesium stearate, stearic acid, modified cellulose gum, and colloidal silicon dioxide.

Product Features

The main ingredient, L-Tryptophan is an amino-acid commonly used in alternative medicine for the ailments like insomnia, anxiety, depression, ADD, and premenstrual syndrome.

Supplements containing L- Tryptophan are not the subject of regulated manufacturing standards, making them potentially dangerous. It is advised to pay special attention to the supplier of the supplement and also to consult a healthcare professional before using such a product. Impure, contaminated L- Tryptophan based supplements (commercialized by a Japanese company) is believed to be the cause of a life threatening disease occurred in the late 1980’s. Furthermore, not all uses for l-tryptophan have been approved by the FDA.

Source Naturals recommends a dose of 1 tablet three times daily, between meals and preferably with fruit juice. For a restful sleep they recommend 3 capsules before bedtime. In the case of the powder, the recommended dose is of ¾ teaspoons. Pregnant or breastfeeding women and women planning to become pregnant, people taking SSRI or MAOI medication are advised to consult a healthcare professional before using this product.

Sale Price: $38.50

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  • Reputable and experienced manufacturer
  • Three different alternatives of the product (tablets, powder or capsules).


  • The supplement is not FDA approved
  • Controversial main ingredient
  • No conclusive evidence of clinical trials conducted upon the product
  • No money back guarantee
  • Mixed reviews from consumers.


L-Tryptophan is a multi targeted amino-acid based, natural formula. It is designed to help induce relaxation and a positive mood and may ensure a restful sleep.

Due to its capacity to convert to niacin, it also supports circulation and health of the nervous system and the production of hydrochloric acid for the digestive system. However the formula’s efficiency is neither clinically proven, nor approved by the FDA. Our readers should be extremely cautious when purchasing a product based on L- Tryptophan. Impure ingredients may lead to severe, potential lethal health conditions.

The manufacturer recommends its use at the advice of the healthcare professional in case of pregnant and nursing women or people under certain kind of medication.

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L-Tryptophan ReviewBR Publishing3.52016-05-20 12:09:31
L-Tryptophan Review
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