L-theanine is mostly found in teas, such as white, green, oolong, and black teas, although it can also be found in small amounts in Bay bolete mushrooms. Out of more than 1,300 chemical compounds found in tea, l-theanine is the most outstanding for its benefits for cognitive and mental well-being.
Take a look at the effects of l-theanine on brain and mental health:
L-theanine increases essential brain chemicals – L-theanine increases the levels of neurotransmitters, which are biochemicals that brain cells use to communicate with each other.L-theanine particularly increases the levels of the neurotransmitters serotonin, dopamine, and gamma-aminobutyric acid (GABA), therefore enhancing recall, learning, and positive mood. L-theanine also boosts two other essential brain chemicals known as brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), which promote the growth of new brain cells and nerve cells.
L-theanine relieves stress and anxiety – L-theanine decreases both psychological and physiological stress responses, enhancing mental resilience. It also lowers heart rate and helps regulate blood pressure under stress. Since it increases GABA, a neurotransmitter that plays an essential role in relaxation, it can improve the symptoms of anxiety. Research also suggested that l-theanine can be an alternative treatment for anxiety, as it has been found to works as well as commonly prescribed anti-anxiety drugs.
L-theanine puts the brain in a calm state – L-theanine can put a state of calm by changing brain waves. It causes an increase in alpha activity, which is the brainwave state linked to relaxation and attention. Its relaxing effect is noticeable after 30 to 45 minutes.
L-theanine boosts cognitive performance – Tea contains both l-theanine and caffeine. Together, these two compounds help improve cognitive performance without leaving you to feel wired. A combination of l-theanine and caffeine is well-known for enhancing alertness, concentration, and mood. It is a safe and effective way to optimize mental performance without using brain-enhancing drugs.
L-theanine protects the brain from deterioration – This compound is also beneficial for older adults because it can protect their brains and keep them mentally sharp. One way it helps prevent mental decline is through improving blood flow to the brain.
Research in traditional tea-drinking countries, such as China and Japan, revealed that older adults who regularly drank tea had higher scores on attention, memory, and information processing compared to those who did not. In other studies, it has been shown to boost cognition and memory even in people diagnosed with mild cognitive impairment. It also protects against stroke and Alzheimer’s, and prevent brain cell death after a stroke. Furthermore, it can protect the brain from environmental toxins believed to contribute to Parkinson's disease.
L-theanine improves sleep quality – Getting high-quality sleep is important for the brain because it is during sleep that brain repair, brain cell growth, and memory consolidation occur – and l-theanine can help improve your sleep quality. It works by helping you sleep better without making you feel tired the following day. (Related: Getting the most out of sleep supplements such as L-theanine.)
There is no known safe L-theanine dosage recommendation because there has been no conclusive research yet. So far, there have been no reports on overdose or side effects of l-theanine supplementation. While drinking tea is generally safe for most people, it is still important to follow the general caffeine consumption guidelines if drinking tea. The recommended maximum consumption of tea is five cups a day.