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L-THEANINE 200, 60 capsules

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L-Theanine is a naturally occurring amino acid found in green tea leaves. It has been found to promote relaxation without drowsiness, easing nervousness due to overwork and fatigue, and support calmness.


Serving Size: 1 Capsule
Servings per container: 60
Pill Size:  #1 Veggie Cap


Ingredient Amount Daily Value
L-Theanine 200 mg **

Other Ingredients: Hypromellose, microcrystalline cellulose, vegetable magnesium stearate, silica.

Gluten Free | Dairy Free | Non-GMO | Vegetarian | Vegan

All NutriKey brand supplements are Pharmaceutical Grade and produced in Certified GMP (cGMP) facilities. All NutriKey brand supplements meet or exceed cGMP standards and are third party tested.


Recommendations: Take 1 to 2 capsules twice daily, or as directed by your healthcare practitioner.

Caution: If you are pregnant, nursing, or taking medication, consult your healthcare practitioner before using.



Thanks to its high bioavailability and simple uptake into the brain, supplementation with L-theanine has been shown to be effective for inducing a variety of psychologically beneficial properties, including stress support (relaxation) and promotion of cognitive function.

Research also suggests that L-theanine administration significantly increases alpha waves in the brain, without decreasing beta waves, thereby inducing relaxation without sedation. Alpha waves are one of the two most frequent types of waves produced in the brain when we are awake, with the other being beta waves.

People who are in a resting state or coming down from a busy set of activities are often in the alpha brain wave space. People who practice light meditation will also be functioning in the alpha brain level.

When we are highly involved, active, or engaged in difficult mental activities your brain waves are functioning at the beta level. Thus, when L-theanine is ingested, users tend to feel more calm but yet attentive.


These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.


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. 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.
4. 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.
5. 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.

Customer Reviews

Based on 7 reviews
Debbie W.
Relaxes Me!

Started taking L-Theanine (200 mg/night) before bed, along with 50 mg of Trazadone & I fall asleep pretty well now & can sleep a bit longer than I did in the past. This is what was said about it: "L-theanine also increases alpha brain waves, which are associated with a state of relaxation. As a result, taking L-theanine supplements can lead to reduced stress and anxiety, improved sleep, and an overall sense of calm and well-being." Sure has made a difference for me. I had some slight stomach upset at first, with green bowel movements, but that has subsided, luckily within a short amount of time. Going more natural is the way to go. I hope to reduce the Trazadone over time as well, when the time is right.

Sue D.
This Works!

I tried the L-Theanine after trying multiple other products to help me sleep through the night. Once I woke up during the night, it was hard to get back to sleep, but the L-Theanine seems to allow me to get back to sleep quickly.

katie s.

If I am stressed or have a lot to do I pop one in and it all seems more manageable. I also take one with my magnesium before better for a good night sleep

Jean S.
Great products!

I take this at night with my Magnesium (for my leg cramps) the two products help my anxiety stay at bay and help me sleep well feeling refreshed in the morning!

Julie R.
It pays to buy quality

I take this for sleeping along with magnesium and it really helps me have a deeper sleep. Lately, I have been buying different brands and i noticed I wasn't sleeping as well and I was waking up much more during the night. I just switched back to this brand and after just one night I have noticed a big difference. I had the best night of sleep in a long time. It pays to buy quality.