The effects of L-theanine consumption on sleep outcomes
L-theanine significantly improved sleep quality, shortened the time it took to fall asleep, and reduced daytime fatigue. The study confirms its potential for improving sleep disorders, although more research is needed.
Faculty of Health, University of Canberra, Bruce, Canberra, Australia
Link to the study
Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults
Daily supplementation with 200 mg of L-theanine for 4 weeks reduced stress and anxiety and improved sleep quality. Cognitive function also improved, especially verbal and executive performance. The results suggest a positive effect of L-theanine on mental health and focus.
Department of Mental Disorder Research, National Institute of Neuroscience, Tokyo, Japan.
Link to the study
Comparison Between Efficacy of Oral Melatonin and Oral L-theanine in Improving Sleep in Cancer Patients Suffering From Insomnia
In cancer patients suffering from insomnia, 14 days of supplementation with 200 mg of L-theanine improved sleep scores compared to placebo.
Department of Anaesthesiology, Karnataka Institute of Medical Sciences, Karnataka, India
Link to the study
The Effects of Green Tea Amino Acid L-Theanine Consumption on the Ability to Manage Stress and Anxiety Levels
Supplementation with 200–400 mg of L-theanine daily helps reduce stress and anxiety in people exposed to demanding conditions. Studies confirm its calming effect on the nervous system. However, larger and longer-term research is needed for precise clinical recommendations.
Faculty of Health, University of Canberra, Canberra, Australia
Link to the study
Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses
L-theanine significantly reduced the rise in blood pressure caused by psychological stress and decreased tension and anxiety compared to placebo. This confirms its ability to blunt the body’s stress response.
Laboratory of Nutritional Biochemistry, School of Food and Nutritional Sciences, University of Shizuoka, Japan
Link to the study
Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together
L-theanine improved reaction time in a socially stressful situation and had a calming effect without increasing blood pressure. Caffeine, on the other hand, raised blood pressure, even though it improved alertness. The combination of both substances may support focus without excessive stimulation.
Department of Experimental Psychology, University of Bristol, UK
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The acute effects of L-theanine in comparison with alprazolam on anticipatory anxiety in humans
A single 200 mg dose of L-theanine reduced anxiety more than placebo and the anxiolytic alprazolam. The effect was seen mainly in subjective mood ratings. This suggests L-theanine may ease stress responses without sedative effects.
Neuropsychopharmacology Laboratory, Brain Sciences Institute, University of Technology, Victoria, Australia
Link to the study
Anti-Stress, Behavioural and Magnetoencephalography Effects of an L-Theanine-Based Nutrient Drink
A single 200 mg dose of L-theanine reduced subjective stress and increased alpha brain activity associated with relaxation. The effect was more pronounced in individuals with higher anxiety. The results confirm its fast-acting calming effect.
Centre for Human Psychopharmacology, Swinburne University of Technology, Australia
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Anti-stress effect of theanine on students during pharmacy practice
Long-term use of 100 mg of L-theanine daily reduced stress, anxiety, and cortisol levels in students during a demanding period. Lower activity of the stress-related enzyme sAA was also observed. This suggests L-theanine helps regulate the body’s response to prolonged stress.
Laboratory of Bioorganic Chemistry, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
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L-Theanine reduces psychological and physiological stress responses
A single 200 mg dose of L-theanine reduced heart rate and levels of stress markers during a stressful task. L-theanine likely exerts its anti-stress effects by calming brain activity.
Nagoya University Department of Psychology, Nagoya, Japan
Link to the study
