Studies on human volunteers: L-theanine creates a sense of alert relaxation about 30-40 minutes after ingestion via at least two different mechanisms: directly stimulates the production of alpha brain waves, creating a state of deep relaxation and mental alertness similar to what is achieved through meditation; is involved in the formation of the inhibitory neurotransmitter GABA, which influences the levels of dopamine and serotonin. (Perrini,Carolyn, CLS, CNC. L-Theanine: How a Unique Anxiety Reducer and Mood Enhancer Increases Alpha Waves and Alertness.

L-theanine is the most predominant free amino acid found in green tea. Reported benefits include:

  • capable of blocking cell death from an excess of glutamate
  • can stimulate the release of nerve growth factor (NGF)
  • can calm both PMS and menopausal symptoms
  • can increase focused attention and improve learning
  • helps to relieve nicotine addiction
  • reduces stress and anxiety
  • triggers release of dopamine, norepinephrine, and serotonin
  • promotes sleep

(Sharpe, Ed. L-Theanine. The Delano Report.

L-theanine, a nonessential amino acid, has been found to reduces stress and anxiety without the tranquilizing effects found in many other calming supplements. The brain absorbs it within 30 minutes of ingesting and its effects can last for hours. (Thankachen, Jasmin. Destress with L-Theanine. Natural Health,Oct-Nov, 2002.

L-theanine, a non-protein amino acid mainly found naturally in tea leaves, is involved in the formation of the inhibitory neurotransmitter GABA (gamma amino butyric acid). GABA influences the levels of two other neurotransmitters, dopamine and serotonin. In addition it stimulates the production of alpha brain waves that can help to control anxiety, increase mental focus, improve concentration, improve memory and learning ability, and promote creativity. It exerts protective effects on the brain by antagonizing glutamate toxicity. (L-Theanine. Vitamins and Health Supplements Guide.

L-theanine, an amino acid found in the leaves of green tea, it has been reported to benefit both the brain and the immune system. It can cross the blood-brain barrier. Benefits include: promotes alpha wave production, and increases the levels of dopamine, serotonin, and GABA in the brain. (Multiple studies cited and references listed. ( ( (

Perhaps one of the most extensively researched and documented nutritional ingredients, L-theanine has demonstrated safety and efficacy in many applications. For example: promoting relaxation with drowsiness; improving learning and concentration; heightening mental acuity; supporting the immune system; lowering cholesterol; and reducing stress and anxiety. (L-Theanine. NutriScience Innovations, LLC.) (

MSG does enhance flavors by plugging into taste receptors on the tongue but it is potentially neurotoxic. L-Theanine functions in the same way but has none of the reported side effects of MSG. (Sharpe, Ed. L-Theanine. The Delano Report.