L-Theanine Benefits and Uses
L-Theanine is an amino acid primarily found in tea leaves, especially green tea, and is also available as a supplement. It is known for its calming and stress-relieving properties without causing drowsiness. Here are the key benefits of L-Theanine:
1. Stress and Anxiety Reduction
Promotes relaxation by increasing alpha brain waves, which are associated with a relaxed yet alert mental state.
Reduces symptoms of anxiety without sedative effects.
2. Improved Focus and Attention
Enhances focus, attention, and mental clarity, especially when combined with caffeine.
Helps prevent the jitteriness often caused by caffeine.
3. Better Sleep Quality
Improves sleep quality by promoting relaxation.
Can help reduce the time it takes to fall asleep and enhance sleep depth.
4. Cognitive Function and Memory
Supports cognitive performance under stress.
May improve short-term memory and overall mental clarity.
5. Mood Enhancement
Positively influences mood by increasing dopamine and serotonin levels.
6. Antioxidant and Neuroprotective Properties
Has antioxidant effects, which help protect brain cells from damage caused by oxidative stress.
May have protective effects against cognitive decline.
Best Ways to Take L-Theanine
Found naturally in green, black, and white teas.
Often taken as a supplement in doses ranging from 100–400 mg per day.
Commonly combined with caffeine (e.g., in a 2:1 ratio of L-Theanine to caffeine) for enhanced focus and alertness.
L-Theanine is generally considered safe, with minimal side effects, but it’s always good to consult with a healthcare professional before starting supplementation, especially if you're on medication.
What is L-Theanine?
Chemically, L-Theanine is an analog of the amino acid glutamine and structurally similar to both glutamate and gamma-aminobutyric acid (GABA)—two neurotransmitters that play important roles in brain function.
Once consumed, it crosses the blood-brain barrier and:
Increases alpha brain wave activity, associated with a calm and alert mental state
Modulates levels of dopamine, serotonin, and GABA
Helps counteract the overstimulation from caffeine, providing balanced focus
How was L-Theanine Discovered?
L-Theanine was first isolated in 1949 by Japanese scientists from gyokuro leaves, a type of high-quality green tea known for its rich umami flavor. Researchers were initially studying what gave green tea its unique taste and calming effects.
Key points from its discovery:
Isolation Year: 1949
Country: Japan
Source: Green tea (Gyokuro)
Research Focus: Understanding tea’s "umami" (savory) flavor and mental clarity properties
Over time, scientific interest grew as researchers uncovered how L-Theanine interacts with the central nervous system, leading to its widespread use in:
Nootropic stacks
Stress-relief supplements
Focus-enhancing drinks and teas
What foods contain L-Theanine?
​L-Theanine is a unique amino acid predominantly found in tea plants (Camellia sinensis). Several scientific studies have explored its presence in various foods:​
1. Tea Leaves
Green Tea: The richest natural source of L-Theanine.
Black Tea: Contains L-Theanine, though slightly less than green tea due to oxidation during processing.
White Tea: Also contains L-Theanine, though in smaller amounts compared to green tea.
Oolong Tea: Contains moderate levels of L-Theanine.
2. Certain Mushrooms
Bay Bolete (Imleria badia): A type of edible mushroom that contains small amounts of L-Theanine.
3. Supplements
Synthetic or naturally extracted L-Theanine is widely available in capsules, powders, and drinks.
4. Functional Beverages
Some energy drinks and relaxation beverages are formulated with added L-Theanine to promote focus and relaxation.
5. Herbal Infusions (Minimal Levels)
Some herbal blends may include trace amounts of L-Theanine if they contain tea extracts or are mixed with tea leaves.
6. Foods with Tea Extracts
Certain chocolates, candies, or functional foods may include green tea or L-Theanine extracts for their calming effects.
If you're looking to increase your L-Theanine intake, green tea and supplements are the most effective and reliable sources. It's important to note that while tea leaves are the primary dietary source of L-Theanine, certain mushrooms also contribute to its intake. The concentration of L-Theanine in these foods can vary based on factors such as the specific variety, cultivation methods, and processing techniques.
References
Sakato, Y. (1950). Studies on the chemical constituents of tea. IV. On a new amino acid in tea. Nippon Nōgeikagaku Kaishi (Journal of the Agricultural Chemical Society of Japan), 24(5), 262–267.
Nobre, A. C., Rao, A., & Owen, G. N. (2008). L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pacific Journal of Clinical Nutrition, 17(S1), 167–168.
Nathan, P. J., Lu, K., Gray, M., & Oliver, C. (2006). The neuropharmacology of L-theanine (N-ethyl-L-glutamine): A possible neuroprotective and cognitive enhancing agent. Biological Psychology, 74(1), 39–45.
Examine.com. (n.d.). L-Theanine.
U.S. National Library of Medicine. (n.d.). L-Theanine - Compound Summary (PubChem).
