Theanine

Theanine or L-theanine, also known as boletus badius, camellia sinensis, gamma-ethylamino-L-glutamic acid or suntheanine, is an amino acid found in green tea that is sometimes taken as a herbal or alternative medicine.

Uses
Theanine is has suggested for:
 * Anxiety
 * Brain fog symptoms (cognitive impairment), e.g. to improve concentration mental alertness, and memory, particularly in combination with green tea extract or caffeine
 * Improving response to conventional cancer treatment or reducing cancer treatment side effects
 * Depression
 * Immune system support
 * Insomnia

Dosage
Doses used in short term clinical trials include:
 * Anxiolytic / anxiety - 200 - 250mg in a single dose
 * Cognitive performance and mental alertness - 97 - 100mg, taken with caffeine
 * Psychiatric symptoms - 240 to 400mg daily, in divided doses

Risks and side effects
Headache, dizziness and gastrointestinal symptoms have been reported.

Availability
Theanine is inexpensive and available over the counter.

Evidence
Evidence is limited for most suggested uses and some trials have reported no benefits or mixed results.

Learn more

 * L-theanine - Memorial Sloan Kettering Cancer Center
 * L-theanine - drugs.com