60 CAPS | 500 MG Product No. 00149

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L-Tryptophan is the essential amino acid that acts as a precursor to 5-HTP, serotonin, melatonin, and niacin. Tryptophan assists with normal sleep patterns, mood, and appetite. Use with care when combining with SSRI’s, or other substances that increase serotonin levels. *

  • Promotes healthy sleep onset, duration, and quality*
  • Supports healthy immune function*
  • Supports balanced mood*
  • Aids in appetite regulation


* These statements have not been evaluated by the Food & Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.



Product Code: 00149                              Capsules per Bottle: 60


Each size 00 vegetarian cellulose capsule contains:


Vitamin B-6 (as Pyridoxine HCl)

10 mg

L-Tryptophan (TryptoPure ™ )

500 mg

  TryptoPure™ is a registered trademark of Ajinomoto Aminoscience, LLC.


What is L-Tryptophan?

L-Tryptophan is an amino acid precursor for the production of both melatonin and serotonin [1]. It is considered an “essential amino acid” as it is not made by the body, and must be ingested as part of the diet or through supplementation. Once absorbed, L-tryptophan is converted into 5-HTP (5-hydroxytryptophan), and then to serotonin [1]. Melatonin, a hormone that regulates diurnal rhythms and influences the reproductive and immune systems, as well as digestive processes and gastrointestinal motility, is also produced in the process of serotonin synthesis [1].


How does L-Tryptophan Work?

The way in which poor sleep can negatively affect performance during the day may be due, in part, to an imbalance of brain serotonin and/or melatonin [2]. Tryptophan supplementation has been shown to improve sleep quality (reduced wakefulness in the night), reduce sleep latency (time until falling asleep), and enhance sustained alertness early in the morning after an overnight sleep [2].

As the sole precursor of serotonin, research has shown that L-tryptophan’s role in brain serotonin synthesis is involved in the regulation of mood, behavior, and cognition [3]. Although serotonin synthesis can be affected by numerous factors, changes to the availability of L-tryptophan has been shown to have the greatest influence on the rate of serotonin synthesis [3]. 

Tryptophan depletion is known to have mood-lowering effects in both men and women, although women and those with a family history of mood disorders tend to be more vulnerable to these particular effects [4]. Tryptophan depletion has also been shown to impair learning, memory retrieval, and cognitive flexibility in otherwise healthy adults as well as increase aggressive and impulsive behaviors in patients with ADHD [4]. 

Amino acids, such as tryptophan, play a significant role in immune response by regulating lymphocyte and macrophage proliferation and function and the production of antibodies. Catabolism of tryptophan also increases the scavenging of free radicals and inhibits the production of some inflammatory cytokines [5].


What are the Suggested Uses for L-Tryptophan?

  • Restful sleep - tryptophan promotes a quicker sleep onset, longer duration, and better quality sleep for improved morning alertness.
  • Healthy immune function
  • Balanced mood/ serotonin support
  • Appetite regulation - tryptophan is a precursor for 5-HTP, which has been shown to regulate and normalize appetite to aid in weight loss or undernourishment.


Source Materials: L-tryptophan is made by fermentation. Pyridoxine HCl is synthetic. Cellulose for capsules is derived from softwood tree pulp. All ingredients are vegan and non-GMO.


Allergens:  According to information provided by our suppliers, these capsules are free of the eight major allergens as identified by the Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA): Wheat (gluten), eggs, milk, soybeans, shellfish, fish, peanuts, tree nuts.


Recommendations: Use as directed by a healthcare professional.


Precautions: Pregnant or lactating women and individuals taking prescription medications should consult with a healthcare professional before taking any supplement.



  1. U. S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Nutritional Products, Labeling, and Dietary Supplements. Information Paper on L-Tryptophan and 5-hydroxy-L-tryptophan, February 2001.
  1. Marcus CR, Jonkman LM, Lammers J, et al. Evening intake of α-lactalbumin increases plasma tryptophan availability and improves morning alertness and brain measures of attention, Am J Clin Nutr May 2005, vol. 81 no. 5 1026-1033
  1. Murphy FC, Smith KA, Cowen PJ, et al. The effects of tryptophan depletion on cognitive and affective processing in healthy volunteers. Psychopharmacology (Berl) 2002;163:42-53.
  1. Richard  DM, Dawes MA, Matthias CW, et al. L-Tryptophan: Basic Metabolic Functions, Behavioral Research and Therapeutic Indications. International Journal of Tryptophan Research 2009; 2: 45–60.
  1. Li P, Yu-Long D, Li D, et al. Amino acids and immune function, British Journal of Nutrition,Volume 98, Issue 2, August 2007 , pp. 237-252



* These statements have not been evaluated by the Food & Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

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