January 22, 2019

L-Theanine is an isomer (specifically an enantiomer, or non-superimposable mirror image) of the amino acids L-glutamate and L-glutamine; it was discovered centuries ago as one of the primary amino acids in green tea leaves.

The cognitive effects of L-theanine are generally summarized as "alert relaxation" (i.e. L-theanine helps relax you without sedating you). 

This makes L-theanine (and green tea) great choices for both stress/anxiety relief and cognitive enhancement. Moreover, L-theanine can also help promote more restful sleep, especially in conjunction with melatonin and 5-HTP.

If you’re a coffee junkie and love the kick of caffeine, L-theanine is the ideal nootropic for attenuating the "high" that stimulants can induce.

In fact, research shows that combining L-theanine with caffeine creates a nootropic synergy that supports cognitive function and alertness more effectively than taking each nootropic on their own.^[2]

Benefits of Using an L-Theanine Supplement

L-theanine is highly bioavailable when taken orally, and it actively crosses your blood-brain barrier; as such, supplementation with L-theanine is an effective measure for promoting anxiety relief, cognitive function, and several other nootropic properties.^[3]

Research also suggests that consuming L-theanine significantly increases alpha waves in the brain but has no effect on beta waves; the result of this is a better sense of relaxation without feeling sleepy or drowsy.^[4]

Alpha and beta waves are two of the most frequent brainwaves, working to regulate our mood. attentiveness, and much more.

When you are in a resting state or coming down from a set of busy activities, you are typically operating in the alpha brainwave space.  Meditation is a prime example of an activity that induces alpha brainwaves.

When you are highly involved, active, or engaged in difficult mental activities, such as studying or taking an exam, your brainwaves are functioning at the beta level. 

Thus, when you consume L-theanine you'll feel more calm but yet attentive.

How L-Theanine Works

After consuming green tea, L-theanine actively crosses your blood-brain barrier and elicits a variety of therapeutic cognitive effects.^[1]

While many nootropics help manage anxiety by increasing serotonin production, L-theanine doesn’t appear to follow that path.

Interestingly, large doses of L-theanine can actually reduce serotonin levels (despite increasing levels of tryptophan in the brain).

In some regards, it’s beneficial that L-theanine doesn’t increase serotonin levels as that could induce drowsiness and disrupt your productivity during the day.

Another benefit of this is that L-theanine pairs well with supplements and prescription medication that fight anxiety by increasing serotonin (and other neurotransmitters) since they don’t compete for the same receptors.

In fact, recent research suggests that pairing antipsychotic medication with 400 mg of L-theanine per day may reduce anxiety symptoms in patients with chronic schizophrenia.^[5]

By the same token, other research shows that even a modest 250 mg of L-theanine per day is safe and effective for reducing the symptoms of chronic depression, insomnia, and cognitive dysfunction.^[6]

Take-Home Points

In summary, research thus far demonstrates that supplementing with roughly 100 - 200 mg of L-theanine per day can provide a variety of benefits, such as:

• Promoting stress management and relaxation without sedation
• Enhancing cognitive function
• Supporting the cardiovascular system and healthy blood pressure^[7]
• Attenuating side effects of stimulants
• Helping with the management of depression and anxiety

Caffeine + L-Theanine is the perfect combination for supporting lasting energy and motivation without jitters and crashing.

References

^[1] Juneja, L. R., Chu, D. C., Okubo, T., Nagato, Y., & Yokogoshi, H. (1999). L-theanine—a unique amino acid of green tea and its relaxation effect in humans. Trends in Food Science & Technology, 10(6), 199-204.

^[2] Haskell, C. F., Kennedy, D. O., Milne, A. L., Wesnes, K. A., & Scholey, A. B. (2008). The effects of L-theanine, caffeine and their combination on cognition and mood. Biological psychology, 77(2), 113-122.

^[3] Kim, T. I., Lee, Y. K., Park, S. G., Choi, I. S., Ban, J. O., Park, H. K., ... & Hong, J. T. (2009). l-Theanine, an amino acid in green tea, attenuates β-amyloid-induced cognitive dysfunction and neurotoxicity: reduction in oxidative damage and inactivation of ERK/p38 kinase and NF-κB pathways. Free Radical Biology and Medicine, 47(11), 1601-1610.

^[4] Song, C. H., Jung, J. H., Oh, J. S., & Kim, K. S. (2003). Effects of theanine on the release of brain alpha wave in adult males. Korean Journal of Nutrition, 36(9), 918-923.

^[5] Miodownik, C., Maayan, R., Ratner, Y., Lerner, V., Pintov, L., Mar, M., ... & Ritsner, M. S. (2011). Serum levels of brain-derived neurotrophic factor and cortisol to sulfate of dehydroepiandrosterone molar ratio associated with clinical response to L-theanine as augmentation of antipsychotic therapy in schizophrenia and schizoaffective disorder patients. Clinical neuropharmacology, 34(4), 155-160.

^[6] Bryan, J. (2008). Psychological effects of dietary components of tea: caffeine and L-theanine. Nutrition reviews, 66(2), 82-90.

^[7] Yokogoshi, H., Kato, Y., Sagesaka, Y. M., Takihara-Matsuura, T., Kakuda, T., & Takeuchi, N. (1995). Reduction effect of theanine on blood pressure and brain 5-hydroxyindoles in spontaneously hypertensive rats. Bioscience, biotechnology, and biochemistry, 59(4), 615-618.

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