Sanesco Blog

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



N-ethyl-L-glutamine, or L-theanine, is the amino acid that draws the spotlight to green tea1. 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 and L.2 We are particularly interested in the L-form as the D-form is not biologically available. Therefore, it does not have the same effects and can even block the absorption of its L-form counterpart3.

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 calming 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 attention issues found that when administered twice daily, L-theanine improved quality of sleep without disrupting their normal bed- and waking times.*6


Green tea is an excellent source of the illustrious L-theanine. However, the amino acid only comprises about 1-2% of green teas leaves’ dry weight.7 That 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, the product of a Japanese manufacturer, is standardized to 99% L-theanine. In a study comparing five other theanine supplements, Suntheanine™ was found to be the only one that was nearly pure.8 Suntheanine™ is so potent and effective it is the predominant source of L-theanine used in research studies exploring its effectiveness for a myriad of health concerns.*

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 exclaimed 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 anxiousness, nervousness, and low mood.*


  1. Juneja, L. R., Chu, D. C., Okubo, T., Nagato, Y., & Yokogoshi, H. (1999). Trends in Food Science & Technology10(6), 199-204; Wakabayashi, C., Numakawa, T., Ninomiya, M., Chiba, S., & Kunugi, H. (2012). 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).  Alternative & Complementary Therapies7(2), 91-95.
  6. Lyon, M. R., Kapoor, M. P., & Juneja, L. R. (2011). 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).

*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.

Miranda Satterfield

Miranda Satterfield

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.

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.

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