molecular structure of L-theanine superimposed on a background of green tea leaves

Suntheanine™ vs. Generic L-Theanine: What’s in a Name?

Posted Connie Shoemaker, ND Blog


N-ethyl-L-glutamine, or L-theanine, is the amino acid that draws the spotlight to green tea[1]. L-theanine provides the calming effects and that characteristic savory, umami flavor of the iconic herbal tea. Like all amino acids, theanine exists in two forms: D-theanine and L-theanine[2]. We are particularly interested in the L-form as they D-form is not biologically available. Therefore, it does not have same effects as L-theanine and can even block absorption of its L-form counterpart[3]. L-theanine is distinguished for many reasons, including alpha-brain wave stimulation and sharpening of focus and attentiveness. Alpha-brain wave transmission induces a sense of calm and relaxation, which is why green tea is praised as a de-stress remedy. [4] Importantly and unlike most other anxiolytic herbs, the L-theanine in green tea welcomes relaxation without bringing on a tide of drowsiness. Alpha-brain wave stimulation also heightens a sense of alertness and awareness that isn’t dampened by feelings of lethargy or grogginess.[5] One study exploring the effects of L-theanine in boys with ADHD, found that when administered twice daily, L-theanine improved quality of sleep without disrupting their normal bed- and waking times.[6]


Although green tea is an excellent source of the illustrious L-theanine, the amino acid only comprises about 1-2% of green teas leaves’ dry weight,[7] which is why many supplement companies have sought extraction and fermentation processes to put adequate doses of L-theanine in a neat little capsule. However, these processes do not always yield 100% or even high concentrations of L-theanine, meaning that they may be equal parts L- and D-theanine. This is a problem that Suntheanine™ brand of L-theanine solved. Suntheanine is the product of a Japanese manufacturer and is standardized to 99% L-theanine. In a study comparing five other L-theanine supplements, Suntheanine™ was found to be the only one that was nearly pure L-theanine.[8] Suntheanine™ is so potent and effective, it is the predominant source of L-theanine used in research studies exploring the effectiveness of L-theanine in treating a myriad of concerns from PTSD to manic depression.

L-theanine in Supplements

When selecting a green tea to sip on, L-theanine content usually corresponds to quality. Teas such as matcha and sencha often have the most L-theanine, while black teas have much less.[9] If green isn’t your cup of tea, Suntheanine has been incorporated into several different food products, such as sodas, chocolate, juices, and other herbal teas.[10] When interviewed about the ingredients in the relaxation drink Just Chill®, the creator exclaims that he and his developers chose Suntheanine™ specifically because of its superiority and efficacy for promoting calm.[11] When choosing an L-theanine supplement, it is important to make sure the product contains Suntheanine™ as its source to safeguard effectiveness and satisfaction. Research suggests that between 50-200 mg of Suntheanine™ is an adequate dose to notice relaxation.[12] In regard to pediatrics, one study administered 400 mg of Suntheanine™ without any notable side effects or adverse reactions.[13] Ready to feel relaxed? Look no further than Sanesco’s Prolent™, Lentra™, and Contegra™ formulas which each contain 75 mg of Suntheanine™ and can be used to alleviate anxiety, nervousness, and depression.


[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 & Technology10(6), 199-204; Wakabayashi, C., Numakawa, T., Ninomiya, M., Chiba, S., & Kunugi, H. (2012). Behavioral and molecular evidence for psychotropic effects in l-theanine. Psychopharmacology, 219(4), 1099-109.

[2] Op cit. Jenega et al. 1999; Vlasov, T. D. (2014). Mechanisms of protection of the brain from ischemic injury by components of tea. Neuroscience and Behavioral Physiology, 44(4), 376-383.

[3] Desai, M. J. and Armstrong, D. W. (2004). Analysis of derivatized and underivatized theanine enantiomers by high-performance liquid chromatography/atmospheric pressure ionization-mass spectrometry. Rapid Commun. Mass Spectrom., 18: 251–256.

[4] Nantz, M. P., Rowe, C. A., Bukowski, J. F., & Percival, S. S. (2009). Standardized capsule of Camellia sinensislowers cardiovascular risk factors in a randomized, double-blind, placebo-controlled study. Nutrition, 25(2), 147-154; Ogasawara, Y., Okubo, T., Ueda, T., & Ozeki, M. (2005). Biological Activities of L—Theanine (Suntheaninetm), an Amino Acid of Green Tea, in Humans.

[5] Mason, R. (2001). 200 mg of Zen: L-theanine boosts alpha waves, promotes alert relaxation. Alternative & Complementary Therapies7(2), 91-95.

[6] Lyon, M. R., Kapoor, M. P., & Juneja, L. R. (2011). The effects of L-theanine (Suntheanine) on objective sleep quality in boys with attention deficit hyperactivity disorder (ADHD): a randomized, double-blind, placebo-controlled clinical trial. Altern Med Rev16(4), 348-354.

[7] Op. cit. Desai 2004; Op cit. Jenega et al. 1999; Op. cit. Mason 2001.

[8] What is Suntheanine? (n.d.). Retrieved June 09, 2017, from

[9] Op. cit. Mason 2001; Op. cit. Vlasov 2014; Ekborg-Ott KH, Taylor A, Armstrong DW (1997) Varietal differences in the total and enantiomeric composition of theanine in tea. J Agric Food Chem 45:353–363.

[10] Op. cit. Mason 2001.

[11] L-theanine: Natural Stress Relief for Calm & Focus. (n.d.). Retrieved June 09, 2017, from

[12] Op. cit. Mason 2001; Op. cit. Ogasawara et al. 2005; Op cit. Jenega et al. 1999.

[13] Op. cit. Lyon (2011).

Clinical Contributor

Miranda Satterfield

Miranda Satterfield

Clinical Support Intern at Sanesco Health
Miranda recently obtained her degree in Cellular Molecular Biology from UNCA in Asheville. Hobbies include running, reading, and exploring the artistic world of drawing and painting.
Miranda Satterfield

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    Disclaimer: The information provided is only intended to be general educational information to the public. It does not constitute medical advice. If you have specific questions about any medical matter or if you are suffering from any medical condition, you should consult your doctor or other professional healthcare provider.