L-theanine
Gamma-glutamylethylamide · 茶氨酸
Supplements. Modern nutrition and Chinese Medicine.
Also called Theanine, Tea amino acid
Pinyin: chá ān suān
Spanish: L-teanina
An amino acid found mainly in tea leaves, sold as a supplement for calm focus and relaxation.
Did you know? L-theanine is mostly found in tea plants, and it adds to the savory taste of green tea.
What it may help, and how strong the proof is
- Stress & anxiety. Small trials show mild calm and lower stress in some people. Results vary, and the effect is modest.Early proof
- Memory & focus. Small trials show better attention when L-theanine is combined with caffeine. Evidence for L-theanine alone is limited.Early proof
Parts of the body
Traditional use
People in China and Japan have long drunk green tea for alertness and calm. The isolated compound is a modern supplement.
How it is classified
- Herbal actions
- Nervine, Brain tonic. Energy: neutral.
How people take it
Studies often used 100 to 400 mg a day. Most people take it in capsules, though green tea also provides a smaller amount.
Capsule, powder and tea.
Where to get it
L-theanine is found mainly in green tea, black tea and matcha, and it is also in some mushrooms. Supplements come as capsules and powders in stores and online.
Be careful
L-theanine is generally well tolerated, with rare headache or upset stomach. Long-term safety in pregnancy and children is not well studied, so check with a doctor first.
Avoid if: pregnancy.
Mixing with other things
- Works well together
Green tea is the main natural source of L-theanine.
The honest take
The calm and focus claims come from small, short trials, and those trials are mixed. It may suit some people, but it is not a proven treatment for anxiety or insomnia. Drinking green tea gives you L-theanine along with other compounds.