L-Theanine and Stress

By Janet Settle MD

In this post, I review the recent article, Anti-Stress, Behavioural and Magnetoencephalography Effects of an l-Theanine-Based Nutrient Drink: A Randomised, Double-Blind, Placebo-Controlled, Crossover Trial written by David White et al and published in Nutrients in January 19, 2016. White, D. J., et al. (2016). Nutrients, 8(1), 53.

L-theanine is an amino acid found in green tea. In this double blind, placebo controlled, crossover study, 34 healthy adults completed a cognitive stressor at baseline and again at 1 and 3 hours after taking 200 mg of L-theanine or placebo.

Compared with placebo, in the L-theanine group:

• Subjective stress levels were significantly reduced at 1 hour but not 3 hours.

• Saliva cortisol levels were significantly reduced at 3 hours but not 1 hour.

• Cognitive performance was non-significantly improved at both 1 and 3 hours.
• Subjects with moderate to high trait anxiety were found to have increased alpha wave brain activity.

Comments: Safe and well tolerated, L-theanine is clinically unique. Name another compound that increases focus and mental clarity while simultaneously reducing stress and anxiety! L-theanine has broad applicability for acute and chronic use for stress, anxiety, and attentional issues. Among the PMC faculty, typical dosing is 200-400 mg BID-TID. PRN doses may be taken up to every 1 hour as needed not to exceed 2000 mg per 24 hours. The serum level peaks at 50 (30-120) minutes following an oral dose. Side effects are rare: no tolerance/ withdrawal, no medication interactions, and no toxicity. The occasional sensitive patient may experience activation. Green tea contains about 25 mg per cup. I endorse green tea as a staple beverage for patients who consume coffee or tea.

Finally, emerging evidence supports L-theanine’s anti-inflammatory and neuroprotective effects in the brain. Based on new data, treatment indications may expand to include use in those with neuroinflammation, traumatic brain injury, neurodegenerative disease and the many patients with cognitive concerns and complaints. I expect more good news to come on this compound!

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Jamwal S. L-theanine, a Component of Green Tea Prevents 3-Nitropropionic Acid (3-NP)-Induced Striatal Toxicity by Modulating Nitric Oxide Pathway. Molecular Neurobiology. 2016 Mar 9. [Epub ahead of print]

Nobre, A. C., Rao, A., and Owen, G. N. L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pac J Clin Nutr 2008;17 Suppl 1:167-168.

Sumathi T. L-Theanine alleviates the neuropathological changes induced by PCB via inhibiting upregulation of inflammatory cytokines and oxidative stress in rat brain. Environ Toxicol Pharmacol. 2016 Mar;42:99-117.