Theanine, also known as L-theanine, is an amino acid found in green tea, an edible mushroom called Boletus badius, and two species related to the tea plant. It has potential use as a relaxant and as a treatment for schizophrenia. It does not typically produce depression or other significant side effects. However, consumption of large amounts of theanine-containing green tea can produce adverse effects other than depression.
Basics
Green tea is derived from the plant Camellia sinensis. Theanine was discovered in green tea leaves in 1949, according to Drugs.com. It accounts for roughly 1 to 2 percent of the dry weight of any given green tea leaf. While amino acids commonly function as building blocks for proteins, theanine only occurs in separate form and does not play a role in protein production. In addition to material extracted from tea leaves, you can purchase a synthetic form of the amino acid called Suntheanine.
Potential Therapeutic Effects
While real-world study of theanine is lacking, it can potentially produce anti-stress or anti-anxiety effects by making you feel relaxed without making you feel drowsy, Drugs.com reports. These effects seem to appear in people who receive single doses of the amino acid that fall in a range between 200 and 250 mg. In a study published in 2010 in the "Journal of Clinical Psychiatry," patients with schizophrenia or schizoaffective disorder received 400 mg of theanine each day for a period of eight weeks. Compared to study participants who received a placebo, participants who took theanine experienced significant reductions in their anxiety levels as well as their main symptoms.
Side Effects
Theanine supplements are regarded as generally safe by the U.S. Food and Drug Administration. Side effects associated with theanine obtained from tea extracts include dizziness, gastrointestinal distress, headaches and irritability. However, Memorial Sloan-Kettering Cancer Center links these effects to the consumption of large amounts of the caffeine in green tea rather than its theanine content. Studies performed on rats indicate that theanine gets absorbed into your bloodstream and tissues. Byproducts from the amino acid pass to your kidneys and are eliminated from your body within roughly one day.
Considerations
Doctors don't have much information on the potential harmful effects of pure theanine, as opposed to the theanine contained in tea extract, Drugs.com explains. In particular, they don't know if theanine is safe for pregnant or lactating women, or if it can alter the effects of various medications. Memorial Sloan-Kettering notes that unwanted interactions with theanine are theoretically possible if you take sedatives, lipid-lowering medications or chemotherapy drugs. If you have sensitivities to green tea, you can avoid potential side effects by staying away from theanine obtained from tea extracts. Consult your doctor before you take a theanine or L-theanine product.
References
- Memorial Sloan-Kettering Cancer Center: L-Theanine
- Drugs.com: L-Theanine
- Psychiatrist.com: L-Theanine Relieves Positive, Activation, and Anxiety Symptoms in Patients With Schizophrenia...; Ritsner, Miodownik, et al.; November 30, 2010
- PubMed.gov: L-Theanine Relieves Positive, Activation, and Anxiety Symptoms in Patients With Schizophrenia...; Ritsner, Miodownik, et al.; "Journal of Clinical Psychiatry"; January 2011
