Overview
A non-protein amino acid found almost exclusively in the leaves of the tea plant, Camellia sinensis — the source of green, black, white, and oolong tea alike. In randomized trials in healthy adults, a single 200 mg dose taken 30–60 minutes beforehand modestly improved choice reaction time on attention tasks, without sedation; results on other cognitive measures, including simple reaction time, are mixed. Effects on stress and anxiety are smaller and less consistent, and one trial using a simulated active-shooter drill found no change in stress markers. Some EEG studies report changes in alpha brain-wave activity, but the direction is mixed and those changes have not been shown to track any calming effect. No serious adverse events have been reported in trials. Not a treatment for any condition.
Proposed mechanism
An amino acid from tea, structurally related to glutamate, that is well absorbed and crosses the blood-brain barrier. It changes alpha-band EEG activity in humans, but not in one consistent direction: studies at rest have reported increases, while studies during demanding attention tasks have reported decreases. Its proposed effects on GABA, serotonin, and glutamate signaling come from animal and cell studies and have not been confirmed in human trials; it does bind glutamate receptors, but far more weakly than glutamate itself. The one trial designed to test whether it offsets caffeine-induced jitteriness found that it did not.
Mechanisms describe how researchers think a compound may act, often from laboratory work — a proposed mechanism is not proof of a clinical effect in people.
Traditional & studied uses
Related pathways
Pathway tags are a research aid for browsing the glossary — they are not a claim that this ingredient treats any condition.