PlainVitamins

L-Tryptophan 500 mg

by Source Naturals · liquid · 100 grams

  • On the market (NIH)
  • UPC 0 21078 01999 2
  • DSLD label 295957
  • Serving 0.5 g (1/4 teaspoon); amounts per 1.5 g
  • 66 servings

L-Tryptophan 500 mg by Source Naturals lists one ingredient: 1.5 g of L-tryptophan per serving of 1.5 g. Its current label entered the NIH Dietary Supplement Label Database on September 25, 2023.

What is in L-Tryptophan 500 mg?

Each row as the label prints it, per serving of 1.5 g. The capsule beside an amount places it among every product in the NIH database that lists the same ingredient: the bar is the middle half of their amounts, the line in it the median, the whiskers the 10th and 90th percentiles; the green tick is the FDA Daily Value and the red dashed tick the adult upper limit (IOM).

L-Tryptophan 500 mg: Supplement Facts rows against the market (DSLD label 295957, January 2026 release)
IngredientAmount% DVAmong products listing it
L-Tryptophan1.5 gTryptophan in L-Tryptophan 500 mg against 605 products1,500 mg per serving; the middle half of products list 55 mg to 471 mg, the median 123 mg.1,500 mg

Higher than 98% of 605 products listing tryptophan (median 123 mg). Per day at the most servings: 4,500 mg.

Source: NIH ODS Dietary Supplement Label Database, label 295957 (entered September 25, 2023), version 9.4.0. See the label on DSLD or its label image (PDF). Amounts are what the maker printed; DSLD does not test products. Daily Values: the FDA's Daily Value page.

Is that a lot?

The rows in the top or bottom tenth of the products that list the same ingredient, and any above the adult upper limit at the most servings a day the directions give:

  • Its 1,500 mg of L-tryptophan (filed by NIH under tryptophan) is higher than 98% of the 605 tryptophan products that print an amount; 8 list more.

The NIH database records 3 servings a day from the label's directions; its % Daily Values are for adults and children 4 or more years of age. The directions as printed are further down this page.

The Tolerable Upper Intake Level is the most of a nutrient per day, from food, water and supplements together, that is likely to pose no risk for almost all adults (Institute of Medicine, 2011). It does not apply under medical supervision. This page compares labels; it is not medical advice.

Sources: amounts from the DSLD label; Daily Values from 21 CFR 101.9(c)(8)(iv); adult upper limits from the Institute of Medicine's DRI summary tables (2011). How positions are computed.

Which products have the closest formulas?

6 products list the very same ingredients; the nearest amounts come first.

Source: ingredient lists of every product's current label in DSLD (version 9.4.0); similarity weights each shared ingredient by how rare it is.

What does the label say about taking it?

Quoted from the label as DSLD transcribed it: the maker's words, including any claim about what the product does, which the FDA has not evaluated and PlainVitamins does not endorse.

Directions
Suggested use: 1/4 teaspoon three times daily, between meals and preferably with fruit juice. To support restful sleep, take 3/4 teaspoon before bed.
Warnings
Caution: If you are pregnant, may become pregnant, breastfeeding, or are taking medications such as SSRI's or MAOI's consult your healthcare professional before using this product.
Do not use if tamper-evident seal is broken or missing.
Keep out of the reach of children.
Allergens and what it does not contain
Suitable for vegetarians and hypoallergenic: contains no yeast, dairy, egg, gluten, corn, soy or wheat. Contains no sugar, starch, salt, preservatives, or artificial color, flavor or fragrance.

Source: label statements in DSLD label 295957.

How many labels does L-Tryptophan 500 mg have?

11 labels are on file under this name since January 25, 2013: other sizes, label designs and reformulations. The current one leads this page.

  1. Label 295957 (current) Entered September 25, 2023 · on the market · 100 grams · UPC 0 21078 01999 2
  2. Label 295956 Entered August 23, 2023 · on the market · 120 tablets · UPC 0 21078 01980 0
  3. Label 295955 Entered August 23, 2023 · off the market July 6, 2022 · 120 capsules · UPC 0 21078 01985 5
  4. Label 295954 Entered August 23, 2023 · off the market July 6, 2022 · 60 capsules · UPC 0 21078 01984 8
  5. Label 273573 Entered March 22, 2023 · on the market · 60 capsules · UPC 0 21078 01984 8
  6. Label 273570 Entered March 22, 2023 · off the market July 6, 2022 · 120 tablets · UPC 0 21078 01980 0
  7. Label 274813 Entered November 22, 2022 · on the market · 60 tablets · UPC 0 21078 01979 4
  8. Label 274809 Entered November 22, 2022 · on the market · 60 tablets · UPC 0 21078 01987 9
  9. Label 72977 Entered April 25, 2017 · off the market December 22, 2021 · 60 capsules · UPC 0 21078 01984 8
  10. Label 72579 Entered April 25, 2017 · on the market · 120 capsules · UPC 0 21078 01985 5
  11. Label 17921 Entered January 25, 2013 · off the market March 24, 2017 · 60 capsules · UPC 0 21078 01984 8

Source: DSLD label entry and market events, version 9.4.0 (labels entered through September 25, 2025).

Who makes it?

The label names Source Naturals, Inc. (manufacturer), Santa Cruz, CA. All Source Naturals products.

Where next?