L-theanine is an amino acid commonly found in tea, but otherwise is not readily available through diet. It has become known to promote relaxation without drowsiness (1),(2),(3),(4) within 30 minutes of ingestion of a dose of 200mg.
Another notable effect is a reduced response to acute stress. (1) (2)
While L-theanine can be taken by itself as a relaxant to calm the nerves, promote relaxation and prepare for a good night's sleep, it is most commonly enjoyed paired with caffeine. As mentioned above, l-theanine is naturally present in tea, which also contains a small amount of caffeine.
Caffeine is a stimulant. A cup of tea contains about 26mg of caffeine (but per the table below, this varies based on the tea) while a cup of coffee contains no less than 95mg. So there's about 4 times more caffeine in coffee than a typical cup of tea, suggesting we would need to supplement with up to 4 times the amount of L-theanine.
Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4787341/
In matcha green tea, you will probably find twice as much caffeine than L-theanine. The two most abundant amino acids in matcha green tea are L-theanine and the less talked about, Arginine. These have a significant stress-reducing effect. This study found that to suppress adrenal hypertrophy in mice, L-theanine is needed above a certain amount. While the level of caffeine in each sample was consistent, the level of L-theanine varied and did not always meet the stress reducing threshold (1). Like all consumer products, it's always good to dig a little deeper and not buy things on face value. Transparent companies will openly publish test results for each batch of their product.
Studies have looked at the the combined effect of 2:1 L-theanine: Caffeine supplementation (1) and results indicate improved accuracy with reduced susceptibility to distraction. This was a low dose study with only 50mg of caffeine - A typical cup of coffee will deliver double that amount, which is why you typically see 200mg of L-theanine in combination supplements.
Try the Kimera Koffee Focus Blend. 300mg of all mighty L-theanine to synergise with the 150mg of caffeine per cup. Kimera Focus provides a perfect two to one ratio of L-theanine to Caffeine.
Stimulating Alpha brain waves for calm free flow thinking that is essential for learning. L-theanine can increase dopamine, GABA and glycine levels in the brain making it ideal for balancing out the unwanted side effects of caffeine like jitters and coffee crash.