Sources of Theanine

Theanine is an amino acid and psychoactive chemical that, according to WebMD, may promote heightened mental awareness much like caffeine, as well as weight loss. Those seeking the benefits of this naturally occurring chemical can find it in several sources, including teas, tea extracts and synthesized food additives.

Brewed Teas

• As with caffeine, you can get your theanine fix with an ordinary cup of tea. According to WebMD, theanine occurs naturally in several types of tea. Green, black, white and oolong teas all contain potentially beneficial amounts of the substance.

Green Tea Extract Supplements

• Those who want the weight-loss properties of theanine but prefer not to drink a hot brewed beverage can take a green tea extract supplement. According to WebMD, such extracts contain catechins and caffeine as well as other substances that help promote weight loss.

Synthesized Food Additives

• According to the Institute for Traditional Medicine, scientists have synthesized theanine from both green tea leaves and the mushroom Xerocomus badius -- the only two common natural sources for the chemical. The U.S. Food and Drug Administration has explored, and determined safe, the addition of theanine to various food products. The FDA cites the opinion of food production company Taiyo International claiming the safe production of theanine "for use as an ingredient in fruit juices and drinks, non-herbal teas, sports beverages, specialty bottled waters, chocolate bars and chews, hard candies and breath mints, and chewing gum at a level up to 250 mg ... per serving."