amino acid · for stress
L-Theanine
Shifts your brain into a relaxed-but-alert state and takes the edge off cortisol.
Say that in clinical terms
L-theanine increases alpha brain wave production (8-14 Hz), creating a relaxed-but-alert mental state. It reduces cortisol and enhances GABA activity, counteracting the physiological effects of acute and chronic stress.
How strong is the research?
Solid evidence
Only one studyIndustry funded
1 paper read, 1 supporting.
Who was studied: Healthy Japanese adults, who tend to drink a lot of green tea already.
How much to take
daily or as needed
200–400 mg
Works within 30-40 minutes for acute stress. Can be combined with ashwagandha for comprehensive stress support.
Before you take it
- No NIH/IOM Tolerable Upper Intake Level (UL) has been established for L-theanine; it is a non-essential amino acid with no Dietary Reference Intake framework.
- May potentiate the blood-pressure-lowering effect of antihypertensive medications through additive hypotensive effects; clinically relevant for users on antihypertensive drugs.
- Insufficient safety data exist for use during pregnancy and lactation; the NIH advises against supplemental L-theanine use when pregnant or nursing a preterm or newborn infant.
- FDA has granted GRAS status to L-theanine for use in specific food/beverage categories at specific commercial doses; this does not constitute a safety ceiling for all supplemental doses or populations.