PlainVitamins

L-Theanine

by XYMOGEN · capsule · 60 vegetarian capsules

  • On the market (NIH)
  • UPC 8 71149 00168 1
  • DSLD label 303741
  • Serving 1 to 2 capsules; amounts per 2 capsules
  • 30 servings

L-Theanine by XYMOGEN lists one ingredient: 400 mg of suntheanine per serving of 2 capsules. Its current label entered the NIH Dietary Supplement Label Database on January 24, 2024.

What is in L-Theanine?

Each row as the label prints it, per serving of 2 capsules. 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-Theanine: Supplement Facts rows against the market (DSLD label 303741, January 2026 release)
IngredientAmount% DVAmong products listing it
Suntheanineas L-Theanine400 mgTheanine in L-Theanine against 1,602 products400 mg per serving; the middle half of products list 90 mg to 200 mg, the median 100 mg.400 mg

Higher than 97% of 1,602 products listing theanine (median 100 mg). Per day at the most servings: 800 mg.

Source: NIH ODS Dietary Supplement Label Database, label 303741 (entered January 24, 2024), 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 400 mg of suntheanine (filed by NIH under theanine) is higher than 97% of the 1,602 theanine products that print an amount; 18 list more.

The NIH database records 2 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
DIRECTIONS: Take one to two capsules twice daily, or as directed by your healthcare professional.
Warnings
Consult your healthcare professional prior to use.
Individuals taking medication should discuss potential interactions with their healthcare professional.
Do not use if tamper seal is damaged.
STORAGE: Keep closed in a cool, dry place out of reach of children.
Allergens and what it does not contain
FORMULATED TO EXCLUDE: Wheat, gluten, corn, yeast, soy, animal and dairy products, fish, shellfish, peanuts, tree nuts, egg, sesame, ingredients derived from genetically modified organisms (GMOs), artificial colors, and artificial sweeteners.

Source: label statements in DSLD label 303741.

What else is on the label?

Other ingredients: Hypromellose, Water, Microcrystalline Cellulose.

Seals and symbols as the label prints them (the maker's; a certifier's own list confirms a seal): ePV (ePedigree Verification); GMP compliant third-party verified.

How many labels does L-Theanine have?

11 labels are on file under this name since March 23, 2012: other sizes, label designs and reformulations. The current one leads this page.

  1. Label 303741 (current) Entered January 24, 2024 · on the market · 60 vegetarian capsules · UPC 8 71149 00168 1
  2. Label 303742 Entered December 14, 2023 · on the market · 120 vegetarian capsules · UPC 8 71149 00239 8
  3. Label 81330 Entered December 22, 2017 · on the market · 120 vegetarian capsules · UPC 8 71149 00239 8
  4. Label 81327 Entered December 22, 2017 · on the market · 60 vegetarian capsules · UPC 8 71149 00168 1
  5. Label 66188 Entered October 22, 2016 · off the market September 29, 2017 · 120 vegetarian capsules · UPC 8 71149 00239 8
  6. Label 66175 Entered October 22, 2016 · off the market September 29, 2017 · 60 vegetarian capsules · UPC 8 71149 00168 1
  7. Label 49911 Entered August 25, 2015 · off the market October 5, 2016 · 120 vegetable capsules · UPC 8 71149 00239 8
  8. Label 49907 Entered August 25, 2015 · off the market October 5, 2016 · 60 vegetable capsules · UPC 8 71149 00168 1
  9. Label 32163 Entered April 25, 2014 · off the market April 28, 2014 · 120 vegetable capsules · UPC 8 71149 00239 8
  10. Label 6138 Entered March 23, 2012 · on the market · 60 vegetable capsules
  11. Label 6137 Entered March 23, 2012 · on the market · 120 vegetable capsules

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

Who makes it?

The label names XYMOGEN Exclusive Professional Formulas (manufacturer), Orlando, FL. All XYMOGEN products.

Where next?