Ingredient

L-tryptophan

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Source
Unknown
Not yet classified by editors
Allergen
No
Role in food
L-tryptophan is added to foods as a nutritional supplement to boost protein content. It …

What it is

L-tryptophan is an essential amino acid, meaning the body cannot make it and it must be obtained from food. It is found naturally in many protein-rich foods like poultry, eggs, dairy, and nuts. It can also be produced industrially through fermentation processes using microorganisms.

Why it's used

L-tryptophan is added to foods as a nutritional supplement to boost protein content. It is also used in some medical foods and dietary supplements. You may find it in protein drinks, meal replacements, and energy bars.

Health notes

L-tryptophan is generally recognized as safe (GRAS) by the FDA when used as a nutrient. It is a precursor to serotonin and melatonin, neurotransmitters involved in mood and sleep. JECFA has evaluated L-tryptophan and established an acceptable daily intake. In the past, a contaminated batch of L-tryptophan supplements led to a serious illness (eosinophilia-myalgia syndrome), but purified L-tryptophan is considered safe.

Allergen info

L-tryptophan itself is not one of the 9 major allergens and does not contain gluten. However, it is often derived from protein sources, so cross-contamination with allergens like soy or dairy is possible depending on the manufacturing process.

Products containing L-tryptophan

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NeoPro Nutritional Sciences, LLC Protein Drink, Orange Other Drinks 24kcal 2.0Protein 0Fat 4.1Carbs Bristol-Myers Squibb/Mead Johnson Nutritionals Vanilla Amino Acid-Based Nutrition Medical Food Powder, Vanilla Energy, Protein & Muscle Recovery Drinks 490kcal 13.7Protein 22Fat 59Carbs Peach Mango Energy Drink, Peach Mango Vital Pharmaceuticals, Inc. Peach Mango Energy Drink, Peach Mango Soda 0kcal 0Protein 0Fat 0Carbs Bratwurst Sausage Made From Plants, Bratwurst Impossible Foods Inc. Bratwurst Sausage Made From Plants, Bratwurst Other Meats High in sodium — 27% DV per serving High in saturated fat — 35% DV per serving 242kcal 13.7Protein 16.8Fat 9.5Carbs Potent Brain And Body Fuel Vital Pharmaceuticals, Inc. Potent Brain And Body Fuel Soda 0kcal 0Protein 0Fat 0Carbs Cheese & Impossible Egg Bites, Cheese Valley Fine Foods Company Cheese & Impossible Egg Bites, Cheese Eggs & Egg Substitutes High in sodium — 23% DV per serving High in saturated fat — 55% DV per serving High in cholesterol — 68% DV per serving 208kcal 13.1Protein 16.1Fat 4.6Carbs Blue Raspberry Energy Drink, Blue Raspberry A SHOC BEVERAGE, LLC Blue Raspberry Energy Drink, Blue Raspberry Soda 2kcal 0Protein 0Fat 0.2Carbs Rainbow Unicorn Potent Mind & Muscle Fuel, Rainbow Unicorn Vital Pharmaceuticals, Inc. Rainbow Unicorn Potent Mind & Muscle Fuel, Rainbow Unicorn Soda 1kcal 0Protein 0Fat 0Carbs Frose Rose Energy Drink, Frose Rose Vital Pharmaceuticals, Inc. Frose Rose Energy Drink, Frose Rose Soda 0kcal 0Protein 0Fat 0Carbs Frose Rose Potent Mind & Muscle Fuel Energy Drink, Frose Rose Vital Pharmaceuticals, Inc. Frose Rose Potent Mind & Muscle Fuel Energy Drink, Frose Rose Soda 1kcal 0Protein 0Fat 0Carbs Mango Bango Natural Energy Drink, Mango Bango Vital Pharmaceuticals, Inc. Mango Bango Natural Energy Drink, Mango Bango Other Drinks 0kcal 0Protein 0Fat 0Carbs Vital Pharmaceuticals, Inc. Radical Skadattle Potent Mind & Muscle Fuel! Energy Blend!, Radical Skadattle Soda 1kcal 0Protein 0Fat 0Carbs
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Last updated: September 28, 2026

Note: This site presents label data from USDA FoodData Central for general information. It is not medical advice. Check the package label; formulations change.