L-Theanine: Amino Acid Stress Manager

Posted at 11:00 - June 25th, 2019 - Megan & Jae - Education Guides

L-Theanine (also referred to as “Theanine”) is a unique free form amino acid found in green tea and various mushrooms. It has been shown to have a calming effect on anxiety without inducing drowsiness or other side effects. Theanine also assists in controlling the hormone cortisol which is produced during the stress response.

As an amino acid, Theanine is one of the building blocks of protein which is derived from various food sources. As with all amino acids, it is vital for overall wellness and healthy biochemical function. Specifically, research has shown that Theanine has a unique ability to calm the Alpha waves of the brain without causing drowsiness. The Alpha waves are sometimes referred to as “brain chatter” because this is the brain wave level where repetitious thoughts contribute to stress and anxiety.

Since Theanine is a protein derived nutrient, it is a normal component of cellular repair and healthy cell function. Unfortunately, the body’s supply of this beneficial amino acid can be depleted by various lifestyle factors such as stress, over work, lack of sleep and poor food choices.

Specifically, caffeine tends to work against Theanine because it’s a stimulant to the central nervous system. Research has shown these effects in the EEGs of rodents as well as the change when Theanine was administered after the caffeine. This includes caffeine in all forms: Coffee, tea, soda, chocolate, etc. In order to achieve maximum benefit from Theanine, caffeine consumption should be minimized or eliminated.

One of the actions of Theanine is its positive impact on brain chemistry. It increases two brain chemicals, GABA and dopamine. Both are known for their ability to calm anxiety and enhance mood. While Theanine increases GABA, caffeine decreases it. As a result, caffeine is a contributor to “brain chatter” and may exacerbate stress.

Clinical studies have shown it to be effective in single dosages as low as 100 to 200 milligrams (daily) which can be increased, as needed, depending on stress and anxiety level. A 100 to 200 milligram dose can be taken four times throughout the day with a total of no more than 600 milligrams during a six-hour period. The effect is generally felt within thirty minutes and may last up to eight hours.

L-Theanine is not affected by food and may be taken any time, as needed. Because it has a mild taste, capsules may be opened and dissolved in water.

The FDA recommends a maximum of 1,200 mgs per day, although the reason for this limit is not clear. There are no known adverse reactions to L-Theanine and no drug interactions have been reported.

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Megan is our product curator and store visionary. Personally vetting every product that comes through the door, she evaluates thousands of items each month with a focus on quality ingredients and value. Well-schooled in the supplements department and the editor of our in-store newsletters, she still insists her main job is raising three daughters! (Wichita, Kansas)


2019 marks Jae’s 20th year working as a Holistic Nutritionist and Supplement Specialist in the Health Food industry. This environment has afforded the opportunity to discuss health issues and solutions with thousands of customers and clients. Along the way, she has acquired multiple certifications including biogenealogy, environmental biology, holistic nutrition and various healing modalities. She is currently studying to complete a Ph.D in Holistic Nutrition.

All Eureka Market Education Guides are intended for educational purposes only. The guides are NOT intended to substitute for professional medical consultation and as such, do not diagnose, prescribe or offer personal medical advice. Always consult with your health care professional before taking supplements with prescription medications.

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