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Ingredient guide

Foods high in L-tryptophan, and how much you need

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

Tryptophan comes from protein foods: turkey, chicken, fish, milk, cheese, egg whites, soybeans, peanuts, and pumpkin, sunflower and sesame seeds. US adults take in about 826 mg a day from food, around three times the average need of 4 mg per kg of body weight.1,2

Key facts

  • Fewer than 1 percent of US adults fall short of the average requirement for any essential amino acid.3
  • A protein-rich breakfast lowered tryptophan's share of the blood's competing amino acids compared with a carbohydrate-rich one.4
  • The liver can turn tryptophan into niacin when there is enough iron, riboflavin and vitamin B6.1
  • In US survey data, most liver and kidney tests were not linked to how much tryptophan people ate.2

Foods that contain tryptophan

Tryptophan is found in cheese, milk, egg whites, chicken, turkey, fish, soybeans, peanuts, and pumpkin, sunflower and sesame seeds.1

  • Meat, poultry and fish: turkey, chicken and fish1
  • Dairy and eggs: milk, cheese and egg whites1
  • Plant foods: soybeans, peanuts, and pumpkin, sunflower and sesame seeds1

The MedlinePlus encyclopedia lists these foods without amounts per serving, so the list is not a ranking. What they have in common is protein. Tryptophan is one of the building blocks of protein, so it arrives with it.1

Do you get enough from food?

US adults typically take in about 826 mg of tryptophan a day from food.2

Fewer than 1 percent of US adults fall below the average requirement for any essential amino acid, tryptophan included.3

Need depends on body weight, at about 4 mg per kg a day on average, so roughly 280 mg for someone weighing 70 kg. Intakes relative to body weight were lowest in the oldest age groups, but across all adults fewer than 1 percent fell below the requirement.2,3

Does turkey make you sleepy?

In 8 adults who ate both, a carbohydrate-rich breakfast and a protein-rich one changed the blood's ratio of tryptophan to its competing amino acids by a median of 54 percent, with the lower ratio after the protein-rich meal.4

Turkey is on the list, but so are chicken, fish and cheese, and none of them is a tryptophan supplement. Protein brings other large amino acids that compete with tryptophan to enter the brain, which is why the protein-rich breakfast lowered tryptophan's share in the blood. The carbohydrate-rich breakfast raised it.1,4

So a big turkey dinner is unlikely to be special because of its tryptophan. The breakfast study measured blood, not sleepiness, and none of the sources here tested turkey itself.4

Tryptophan and niacin

About 60 mg of tryptophan is generally counted as equal to 1 mg of niacin; a study of young women on a controlled diet estimated about 67 mg.5

The conversion takes place in the liver and depends on having enough iron, riboflavin and vitamin B6. It is one reason niacin and tryptophan are linked in nutrition: some of the niacin your body uses can come from the tryptophan in your food.1,5

Food or a supplement?

A supplement delivers tryptophan without the competing amino acids that come with protein, which is how it raises tryptophan in the brain and the serotonin made from it. Food has a different record: in US survey data, even the highest food intakes stayed within normal ranges on most liver and kidney tests.2,6

If you take a serotonin medicine

Drug labels list tryptophan as a serotonergic drug, and MedlinePlus lists it as a nonprescription product, so their warnings about serotonin syndrome concern tryptophan taken as a supplement. Ask your pharmacist if you are unsure how they apply to you.7,8

Questions people ask

Which foods have the most tryptophan?

Protein foods are the sources: poultry, fish, milk, cheese, egg whites, soybeans, peanuts and seeds. The sources we use do not give amounts per serving, so we do not rank them.1

Can I get enough tryptophan on a plant-based diet?

Soybeans, peanuts and pumpkin, sunflower and sesame seeds all contain it. The survey data cover all US adults rather than people who eat no animal foods, so they do not answer this directly.1,3

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Sources

  1. MedlinePlus Medical Encyclopedia. Tryptophan. U.S. National Library of Medicine. Review date April 30, 2026. Opened 2026-10-07.
  2. Lieberman HR, Agarwal S, Fulgoni VL 3rd. Tryptophan Intake in the US Adult Population Is Not Related to Liver or Kidney Function but Is Associated with Depression and Sleep Outcomes. J Nutr. 2016;146(12):2609S-2615S. Opened 2026-10-07.
  3. Berryman CE, Cheung SN, Collette EM, Pasiakos SM, Lieberman HR, Fulgoni VL 3rd. Amino Acid Intake and Conformance With the Dietary Reference Intakes in the United States: Analysis of the National Health and Nutrition Examination Survey, 2001-2018. J Nutr. 2023;153(3):749-759. Opened 2026-10-07.
  4. Wurtman RJ, Wurtman JJ, Regan MM, McDermott JM, Tsay RH, Breu JJ. Effects of normal meals rich in carbohydrates or proteins on plasma tryptophan and tyrosine ratios. Am J Clin Nutr. 2003;77(1):128-132. Opened 2026-10-07.
  5. Fukuwatari T, Ohta M, Kimura N, Sasaki R, Shibata K. Conversion ratio of tryptophan to niacin in Japanese women fed a purified diet conforming to the Japanese Dietary Reference Intakes. J Nutr Sci Vitaminol (Tokyo). 2004;50(6):385-391. Opened 2026-10-07.
  6. Fernstrom JD. Effects and side effects associated with the non-nutritional use of tryptophan by humans. J Nutr. 2012;142(12):2236S-2244S. Opened 2026-10-07.
  7. Sertraline hydrochloride tablets: prescribing information (Cipla USA Inc.). DailyMed, U.S. National Library of Medicine. Published June 23, 2026. Opened 2026-10-07.
  8. MedlinePlus Drug Information. Sertraline. U.S. National Library of Medicine. Last revised October 15, 2025. Opened 2026-10-07.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.