Clinical studies have continued to confirm the numerous benefits of Suntheanine®. Below please find some brief summaries and links to more in-depth research and abstracts. If you have any questions regarding the research behind HandyCaps, please contact us with your questions.

You can also find more research on Suntheanine® on our research listing page.

Effects of Suntheanine on the release of alpha waves in human volunteers.

L-theanine, an amino acid has applications in immune enhancement, stress management, and physical and mental relaxation. For these reasons, it may also be applicable to performance nutrition. One study demonstrated the effects of L-theanine (as Suntheanine®, manufactured by Taiyo Kagaku in Yokkaichi, Japan, and distributed by NutriScience Innovations, Fairfield, Conn., and Cyvex Nutrition in Irvine, Calif.) on alpha-brain waves in humans, which illuminate states of relaxation. Researchers from Taiyo Kagaku discovered that L-theanine encouraged relaxation in subjects without inducing drowsiness

Kobayashi A, et al. Nippon Nogeikagaku Kaishi. 1998 v72, 153-157.
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L-theanine is an amino acid and has been known to decrease serotonin and increase norepinephrine in rat brains, and also reported to produce mental relaxation, lower blood pressure and improve learning ability in human beings. But, few studies on these effects for human beings have been conducted so far. This study was conducted to evaluate the effect of L-theanine on the release of brain alpha waves known to be related with mental relaxation and concentration. Twenty healthy male volunteers aged 18 to 30 years without any physical and psychological diseases were recruited through written advertisement. Alpha power values of EEG as a surrogate marker of mental relaxation and concentration were measured in frontal and occipital regions for 400 minutes after administration of four placebo or test tablets and 20 minute resting period. The results of this study suggest that L-theanine containing tablets promote the release of alpha waves related to mental relaxation and concentration in young adult males.

Song, Chan Hee; Jung, Ju Hae, Oh, Je Sung; Kim, Kyug Soo
Biol Pharm Bull 2002 Dec;25(12):1513-8

Possible neuroprotective effect of Suntheanine.

We investigated the molecular mechanism underlying the neuroprotective effect of theanine, using primary cultured rat cortical neurons, focusing on group I metabotropic glutamate receptors (mGluRs). Theanine and a group I mGluR agonist, DHPG, inhibited the delayed death of neurons caused by brief exposure to glutamate, and this effect of theanine was abolished by group I mGluR antagonists. Although the administration of glutamate alone decreased the neuronal expression of phospholipase C (PLC)-beta1 and -gamma1, which are linked to group I mGluRs, their expression was equal to the control levels on cotreatment with theanine. Treatment with theanine or DHPG alone for 5-7 days resulted in increased expression of PLC-beta1 and -gamma1, and the action of theanine was completely abolished by group I mGluR antagonists. These findings indicate that group I mGluRs might be involved in neuroprotective effect of theanine by increasing the expression levels of PLC-beta1 and -gamma1.

Nagasawa, K. Biochem. And Biophys. Research Communications 320 (2004) 116-122.
www.ncbi.nlm.nih.gov