What it is
A non-proteinogenic amino acid found primarily in tea leaves (Camellia sinensis). Available as oral capsules and tablets.
How it works
Crosses the blood-brain barrier and is proposed to modulate glutamate and GABA neurotransmission and increase alpha-wave activity on EEG in clinical studies.
Where it's used
Used as a dietary supplement marketed for relaxation and as a complement to caffeine for focused calm.
FDA-approved use
Regulated as a dietary supplement; recognized as GRAS for food use.
Tracking it
L-Theanine is oral, which makes consistency the whole game — a simple daily check-off with a reminder beats memory every time. with a half-life of about 1.2 hours, a dose log also lets a tracker model the relative amount still in your system between doses.
Source
Public reference
Not medical advice. This page is an educational summary compiled from public
sources for people who log what they take. It is not a recommendation to use
L-Theanine, a dosing guide, or a substitute for a clinician.
How we source →
Last reviewed 2026-06-11