L-Theanine
ColorantsCAS: 3081-61-6
This is what the ingredient is.
L-Theanine is an amino acid found primarily in tea leaves. Promotes relaxation without drowsiness.
Here is why it shows up on the label.
It works as a functional ingredient for relaxation. Used in beverages, supplements, and functional foods.
Here is what food agencies say.
The FDA lists L-Theanine as Generally Recognized as Safe. Sold as supplement and food ingredient.
Here is what research has found.
May promote relaxation and focus without sedation. Often combined with caffeine. Crosses blood-brain barrier.
Here are a few things worth knowing.
Generally well-tolerated. May interact with blood pressure medications. Limited long-term data.
Sources
- FDA GRAS
- Clinical Studies
How to read this page
We publish plain facts about this ingredient so a label is easier to read. This is not medical advice, and it is not a recommendation to buy, avoid, or use anything. For a personal health question, talk with a clinician who knows your history.
v1.0Updated 9/12/2026