Theanine

What is theanine?

Theanine or 5-N-ethylglutamine is a nonessential amino acid found in green tea; it gives it an umami (savory) taste.

Theanine Functions in the Human Body

Theanine may affect the release of certain neurotransmitters, such as dopamine, in the brain ^[1].

Theanine Supplements

L-theanine oral supplements are available without prescription (over-the-counter).

Theanine Health Benefits

There is INSUFFICIENT EVIDENCE about theanine effectiveness in the prevention or treatment of anxiety, dementia including Alzheimer’s disease and high blood pressure, or in increasing the effects of cancer drugs ^[2].

Some small studies have suggested L-thiamine could reduce anxiety and improve sleep in attention deficit hyperactivity disorder (ADHD) but more research is warranted ^[29].

Theanine Safety: Side Effects, Toxicity

Theanine supplements are POSSIBLY SAFE when used short-term ^[2].

Side effects of theanine may include headache and gastrointestinal problems ^[2].

Not enough is known about the safety of theanine supplements during pregnancy and breastfeeding, so women in these periods should avoid them ^[2].