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Tryptophan is an amino acid needed for normal growth in infants and for nitrogen balance in adults. It is an essential amino acid. This means your body cannot produce it, so you must get it from your diet.


The body uses tryptophan to help make niacin and serotonin. Serotonin is thought to produce healthy sleep and a stable mood.

In order for tryptophan in the diet to be changed into niacin, the body needs to have enough:

  • Iron
  • Riboflavin
  • Vitamin B6

Food Sources

Tryptophan can be found in:

  • Cheese
  • Chicken
  • Chocolate
  • Eggs
  • Fish
  • Milk
  • Peanut butter
  • Peanuts
  • Pumpkin seeds
  • Sesame seeds
  • Soy
  • Tofu
  • Turkey


Murray MT. 5-Hydroxytryptophan. In: Pizzorno JE, Murray MT, eds. Textbook of Natural Medicine. 4th ed. St. Louis, MO: Elsevier Churchill Livingstone; 2013:chap 98.

United States Department of Health and Human Services; United States Department of Agriculture. 2015-2020 Dietary Guidelines for Americans. 8th ed. Updated December 2015. health.gov/dietaryguidelines/2015/guidelines/. Accessed January 15, 2016.

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Review Date 1/31/2016

Updated by: Emily Wax, RD, The Brooklyn Hospital Center, Brooklyn, NY. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.