Benefits of Theanine

By: the editors of PureHealthMD

A calming extract of green tea, theanine, is gaining a significant reputation among nutritional practitioners for its positive effects on anxiety. Other benefits, which are attributed to green tea’s antioxidant epigallocatechin gallate (EGCG), include assistance in the fight against cancer and heart disease.

Theanine has had significant clinical results for naturally calming and focusing the brain. The nutrient seems to help center a mind that is often running in several different directions. Research is still limited in humans, but small studies have pointed to some antianxiety effect as well [Source: Kimura, Lu]. Patients typically describe effects as mild, but helpful. The soothing quality may also benefit those who aren’t necessarily anxious, but can’t relax the mind at night before sleep, and those with muscle tension in the neck.


Studies in animals indicate that theanine may also have protective effects for the brain [Source: Kakuda, Nathan]. It seems to protect the body from excess glutamate, a natural neurotransmitter that allows signaling between nerves. This chemical can be toxic to nerve tissue if levels are not regulated. Theanine shows some protective effects on nerve cells when there is decreased blood flow (caused by a stroke, etc.). Protection of brain cells could play an important role in illnesses that concurrently cause anxiety, such as Alzheimer’s disease.

Cholesterol damaged by inflammation becomes much more toxic to the body. Theanine can help prevent this damage [Source: Yokozawa]. It has also been shown to enhance the effectiveness of various types of chemotherapy drugs in animal studies. This is extremely important, as anxiety is often a consequence of a cancer diagnosis. Theanine, as a supplement, can relieve anxiety brought on by treatment and actually complement some types of chemotherapy [Source: Sugiyama, Sadzuka].

This green tea offspring is well tolerated in supplement form. Hopefully, its antianxiety benefits will be confirmed through more clinical research. Theanine can aid those who have used heavier anxiety medications in the past. Though, an abrupt substitution is not advised. Products like Xanax, Valium or Klonopin should be gradually reduced, under the guidance of a healthcare provider.

Theanine is typically listed as L-theanine, with the “L” being a scientific notation of its structure. Typically dosing is 100-200 mg once to twice a day. Theanine should not affect driving abilities, but as with any anti-anxiety medication or supplement, one should use caution until all potential side effects have been exposed in a controlled environment.

Can you gain the same effects by simply drinking green tea? If so, how much should you consume per day?

Some patients experience a calming, relaxing effect just from sipping on a nice glass throughout the day. That said, the content of theanine in a glass of green tea is substantially less than the concentrated extract in a capsule. Even with several servings, one could not get the same effect as 1-2 capsules of theanine a day. Green tea does offer many other beneficial ingredients, so this should not discourage readers from enjoying a refreshing cup.

Is it safe to take theanine along with prescribed antianxiety medications?

Little, if any, study has been done on the effect of combining theanine with other antianxiety medications. Many patients have tolerated prescribed anxiety medications with additional theanine. Patients on antianxiety medications should not stop any anxiety medicine without the help of the prescribing physician, and let their physician know if they would like to consider adding theanine before implementing this supplement.


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Related Articles

  • Kimura, K. (2007). L-Theanine reduces psychological and physiological stress responses. Biol Psychol, 74(1):39-45.
  • Lu, K. (2004). The acute effects of L-theanine in comparison with alprazolam on anticipatory anxiety in humans. Hum Psychopharmacol.
  • Kakuda, T. (2002). Neuroprotective effects of the green tea components theanine and catechins. Biol Pharm Bull, 25(12):1513-819(7):457-65.
  • Nathan, P.J. (2006). The neuropharmacology of L-theanine (N-ethyl-L-glutamine): A possible neuroprotective and cognitive enhancing agent. J Herb Pharmacother, 6(2):21-30.
  • Yokozawa, T., Dong, E. (1997). Influence of green tea and its three major components upon low-density lipoprotein oxidation. Exp Toxicol Pathol, 1997 49(5):329-35.
  • Sugiyama, T. (2003). Theanine and glutamate transporter inhibitors enhance the antitumor efficacy of chemotherapeutic agents. Biochim Biophys Acta, 1653(2):47-59.
  • Sadzuka, Y. (2000). Improvement of idarubicin induced antitumor activity and bone marrow suppression by theanine, a component of tea. Cancer Lett, 158(2):119-24.
  • Sadzuka, Y. (1996). The effects of theanine, as a novel biochemical modulator, on the antitumor activity of adriamycin. Cancer Lett, 105(2):203-9.