L-Tryptophan 500 mg®

Other Combinations

Brand: Source Naturals

Tablet or PillOther CombinationsOff Market

Product label for L-Tryptophan 500 mg — Click to view full label

Net Contents

120 Tablet(s)

Serving Size

1 Tablet(s)

Servings Per Container

Supplement Form

Tablet or Pill

Bar Code (UPC/SKU)

0 21078 01980 0

Product Version

SN1980 REV J201 FG-113977

Label Analysis

Objective insights generated automatically from the official DSLD label — a quick, factual read of how this product is formulated and disclosed.

3Active Ingredients

3 distinct active ingredients are disclosed in Supplement Facts.

100%Amount Transparency

Every active ingredient discloses a specific amount per serving.

2% Daily Value Coverage

2 ingredients report an established %DV per serving.

3Dietary Attributes

Label states: Vegetarian, Non-GMO, Gluten-Free.

This analysis is generated algorithmically from label data for educational reference only. It is not a product endorsement, ranking, or medical advice.

Allergen Guide

Contains

Milk
Egg
Wheat
Soy
Gluten

Allergen flags are parsed automatically from the official label's claims and statements. Always verify against the physical product label before use, especially if you have a severe allergy.

Supplement Facts

Serving Size: 1 Tablet(s) · 3 per day

Ingredient	Amount Per Serving	% Daily Value
Calcium(Dibasic Calcium Phosphate)	48 mg	4%
Iron	0.6 mg	3%
L-Tryptophan	1.5 Gram(s)	—
Niacin	25 mg	—

Not Present

Other Ingredients

Dibasic Calcium PhosphateStearic Acidmodified Cellulose GumSilica

Target Groups

VegetarianAdult (18 - 50 Years)Gluten FreeDairy Free

Label Claims

NutrientAll OtherStructure/Function

Directions & Suggested Use

Suggested/Recommended/Usage/Directions

Suggested Use: 1 tablet three times daily, between meals and preferably with fruit juice. To support restful sleep, take 3 tablets before bed.

Warnings & Precautions

Precautions re: Pregnant or Nursing or Prescription Medications

Caution: If you are pregnant, may become pregnant, breastfeeding, or are taking medications such as SSRIs or MAOIs consult your health care professional before using this product.

Precautions re: All Other

Do not use if either tamper-evident seal is broken or missing.

Precautions re: Children

Keep out of the reach of children.

Precautions re: Children

Warning: Accidental overdose of iron-containing products is a leading cause of fatal poisoning in children under 6. Keep this product out of the reach of children. In case of accidental overdose, call a doctor or poison control center immediately.

Storage

Store in a cool, dry place.

Formulation

Formulation re: Other

Mood, relaxation, sleep

Formula re: Contains

The essential amino acid L-tryptophan helps support relaxation, restful sleep, and feeling better. It plays a part in the synthesis of both melatonin and serotonin, hormones involved with mood and stress response. L-Tryptophan also supports immune functions because it is the body's precursor to the kynurenines that regulate immunity. If needed, L-Tryptophan converts to niacin in the body, which supports circulation, a healthy nervous system, the metabolism of food, and the production of hydrochloric acid for the digestive system. Source Naturals L-Tryptophan is extremely pure and is regularly tested to ensure the highest standards of quality.

Formulation re: Vegetarian/Vegan

Suitable for Vegetarians.

Formulation re: Does NOT Contain

Contains no yeast, dairy, egg, gluten, soy or wheat. Contains no preservatives, or artificial color, flavor or fragrance.

Formulation re: Does NOT Contain

Non GMO Validated

FDA Statements

FDA Statement of Identity

Dietary Supplement

FDA Disclaimer Statement

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

Other Label Statements

Seals/Symbols

Non GMO Validated

Brand IP Statement(s) re: (c), (TM), (SM)

Manufacturer & Distributor

Distributor

Source Naturals, Inc.

P. O. Box 2118, Santa Cruz, CA, 95062

Market Reference

$9.99 – $124.50· 40 listings

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Where to Buy Locally

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Showing representative supplement & health retailers — search above for stores in your area.

GNC
4.1 (134)
Vitamin & supplements store
494 Gateway Dr, Brooklyn, NY 11239
Directions (718) 277-0979
The Vitamin Shoppe
4.4 (122)
Vitamin & supplements store
8929 Avenue D C1, Brooklyn, NY 11236
Directions (718) 629-2076
GNC
4.5 (53)
Vitamin & supplements store
2155 A Ralph Ave, Brooklyn, NY 11234
Directions (347) 875-4578
The Vitamin Shoppe
4.3 (183)
Vitamin & supplements store
12 4th Ave, Brooklyn, NY 11217
Directions (718) 858-8314
GNC
4.0 (92)
Vitamin & supplements store
133-40 79th St, Queens, NY 11414
Directions (718) 296-4107
The Vitamin Shoppe
4.3 (142)
Vitamin & supplements store
1326 Kings Hwy, Brooklyn, NY 11229
Directions (718) 382-2535
GNC
4.2 (118)
Vitamin & supplements store
56-18 Myrtle Ave, Ridgewood, NY 11385
Directions (718) 417-7316
The Vitamin Shoppe
4.3 (205)
Vitamin & supplements store
107-60 Queens Blvd, Forest Hills, NY 11375
Directions (718) 520-8147

Research & Studies

Tryptophan As A Nutraceutical–Clinical And A Critical
MR Suchitra, P Krubaa, S Parthasarathy - European Journal of Molecular & … - academia.edu
… L Tryptophan is available in the commercial product as 125 mg/ capsule or 500 mg/ capsule … was lowered in preeclamptic compared with the healthy placental arteries, consistent with …
5-Hydroxytryptophan (5-HTP): Natural occurrence, analysis, biosynthesis, biotechnology, physiology and toxicology
ME Maffei - International journal of molecular sciences, 2020 - mdpi.com
… L-tryptophan [68], TPH was un-competitively inhibited by tetrahydropapaverine with the substrate L-tryptophan… to be competitive with the substrate L-tryptophan and non-competitive with …
2020320 citations
L-Tryptophan: Sources and Benefits
L Does, TMY Sleepy - qualialife.com
… that L-tryptophan has niacin equivalent activity in the body (ie, we can make NAD + molecules from it). L-tryptophan … not be considered medical advice. Please speak with an appropriate …
Tryptophan: biochemical and health implications
H Sidransky - 2001 - api.taylorfrancis.com
… L-tryptophan, an important indispensable amino acid, may act. Overall, it becomes apparent that L-tryptophan … The role of L-tryptophan in health and disease has become apparent from …
200146 citations
Regulatory Disparities and Consumer Misperception in Cross-Border Dietary Supplements
SI Park, HJ Park - Food Supplements and Biomaterials for Health, 2026 - e-fsbh.org
2026
Oral tryptophan activates duodenal aryl hydrocarbon receptor in healthy subjects: a crossover randomized controlled trial
GH Rueda, N Causada-Calo… - American Journal …, 2024 - journals.physiology.org
… with l-tryptophan supplementation, which is not surprising as this study was performed in healthy … l-Tryptophan supplementation did not affect cytokine production by PBMC with placebo, …
202428 citations

Data sourced from the U.S. National Institutes of Health, Office of Dietary Supplements Dietary Supplement Label Database (DSLD) · Label entered 2023-03-22. DSLD Label ID: 273570. This information is provided for educational reference only and is not medical advice. Always follow the product label and consult a doctor or pharmacist before use.