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L-Theanine and Stress-Induced Anxiety

L-Theanine and Stress-Induced Anxiety

Carolyn Mercer, B.Sc., N.D.

19 Aug 2021

L-Theanine and Stress-Induced Anxiety

L-Theanine is an amino acid first found in green tea leaves back in the mid 1950's. It works by preventing the binding of L-glutamic acid to glutamate receptors, which inhibits the neural excitation response in the brain.

This action was found to have anti-stress effects and to have beneficial effects on cognition and mood.1

L-Theanine has also been found to boost levels of GABA, Serotonin, and Dopamine.  These neurotransmitters work to regulate emotions, mood, concentration, alertness, energy, and cognitive skills.  L-Theanine further lowers excitatory brain chemicals (epinephrine/norepinephrine) and stimulates alpha brain waves. Together, all this enhances relaxation, focus, and creativity. 

Research has shown, it can be beneficial in many disorders such as anxiety, depression, insomnia, and inattentiveness.2

L-Theanine passes the blood brain barrier, and the effects, such as reductions in stress and increased focus and memory, can be “potent”.
L-Theanine is a beneficial supplement to consider for learning, especially in a classroom setting.3


One other study tested individuals with cognitive impairments. Those who took L-Theanine, improved upon verbal fluency.4

A single dose of L-Theanine reduced the reaction time to attention tasks.  Those who took L-Theanine had an increased number of correct answers on working memory tasks, providing evidence that it can improve attention and enhance working memory and executive functions.5

Yet another study tested individuals while doing arithmetic tasks. Those taking L-Theanine had lower heart rates and reduced amounts of stress or anxiety, making it a potential therapy for reducing test anxiety and improving overall exam performance.6

Typically, dosages of 200-400 mg of L-Theanine have been shown to reduce stress and anxiety in stressful situations.7 Even in elementary students, dosages of ~ 50 mg of L-Theanine (half a chewable tablet) is a good starting dose. 
Dosages of 100-200 mg have been used and found to be beneficial in high school students.2

With all the benefits listed above, consider adding L-Theanine to your child’s back to school supplement regime to enhance learning and performance.  But also to make school more enjoyable.



  1. Yoto, Ai, et al. 2012. “Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses,” Journal of Physiological Anthropology 31, 28 (October), (accessed July 22, 2021).
  2. Boise Natural Health Clinic. Mental Health: L-theanine: A Supplement for Children (and Adults) with Anxiety and Trouble Focusing. (access July 22, 2021).
  3. Nootropics Club. L-Theanine Improves Memory and Learning. (accessed July 23, 2021).
  4. Hidese, Shinshuke et al. 2019. “Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Control,” Nutrients 11(10) (October), (accessed July 22, 2021). 
  5. Yoshitake, Baba et al. 2021. “Effects of L-Theanine on Cognitive Function in Middle-Aged and Older Subjects: A Randomized Placebo-Controlled Study,” Journal of Medicinal Food 24(4) (April), (accessed July 23, 2021).
  6. Gong, Henry. 2014. “Improving College Exam Performance with L-Theanine and Caffeine,” PIT Journal, (accessed July 23, 2021).
  7. Williams, Jackson, 2020. “The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels: a Systematic Review,” Plant Foods for Human Nutrition 75, (November), (accessed July 24, 2021).

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