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L-Theanine is a non-protein amino acid exclusively found in tea plants. It is the major amino acid found in green tea leaves and the one responsible for the signature umami taste of the world’s most consumed beverage. Despite containing caffeine, tea is known to give calming and relaxing effect which is also attributed to having high levels of natural l-theanine. Approximately, 1-2% of the weight of tea leaves is purely this neurologically-active amino acid.

The medicinal and nutritional value of L-theanine is due to its ability to regulate the levels of three important neurotransmitters (brain chemicals) namely: GABA (gamma-aminobutyric acid), Serotonin, and Norephinephrine. L-theanine increases the production of GABA, a major inhibitory neurotransmitter that naturally generates a feeling of calmness and relaxation. L-theanine affects serotonin just like GABA. Serotonin is responsible for controlling emotions like happiness and anger. When there is more serotonin made and distributed in the bloodstream, the better you will be at controlling your emotions. Opposite to the first two neurotransmitters, l-theanine decreases norepinephrine levels in the body. When released, norephinephrine occurs a “fight-or-flight” status in which the body becomes extremely alert. Decreased norepinephrine reduces anxiety, hypertension, and stress which are results of the “fight-or-flight” state.

L-Theanine Benefits

  • L-theanine creates a feeling of relaxation. According to a research on human volunteers, this effect is achieved 30-40 minutes after taking L-theanine supplements.
  • By increasing the levels of dopamine, l-theanine may relieve symptoms of depression. Depression is a response to low levels of neurotransmitters like dopamine.
  • As it regulates serotonin levels, L-theanine improves cognitive abilities like learning and memory. It also enhances attentiveness and focus.
  • The effect of l-theanine on serotonin levels also helps alleviate anxiety and stress. It will greatly help you to perform all your daily tasks without being so stressed out. Taking 50-200 g of l-theanine everyday is a great help in stress management.
  • L-theanine is also suggested to boost the immune system, just like other multivitamins. Stress is a major factor contributing to an immune-compromised status. Taking l-theanine capsules will strengthen the body’s defense against common infections.
  • By lowering norephineprine levels, l-theanine is a potential anti-hypertensive agent. Norephinephrine regulates the body’s blood pressure and when it increases, there is also a corresponding increase in the systolic and diastolic pressure in the arteries.
  • L-theanine supplements are also safer alternatives for sleeping pills. It doesn’t make you sleep, but it gives you the feeling of tranquility and calmness so you can naturally go to sleep.

L-Theanine Side Effects

According to l-theanine reviews, there are only few possible known l-theanine side effects including headache, upset stomach, and dizziness.