L-Theanine For Sleep And Better Mood

Green tea is well known for its high amounts of antioxidants, particularly one known as epigallocatechin gallate or EGCG. However, green tea also contains a high amount of an amino acid known as L-theanine.

L-theanine is widely used and studied in Japan, a culture particularly known for their tea consumption.

L-theanine has been observed to promote relaxation and reduce stress by a variety of possible mechanisms, with clinical evidence also showing these benefits.

Studies have shown that L-theanine increases alpha-wave activity in the brain,19 as well as the levels of serotonin, dopamine and GABA.

L-theanine has been shown to be neuroprotective, in part by having an antagonistic effect on glutamate subtype AMPA receptors, also increasing glutathione as well as its related antioxidant enzymes (superoxide dismutase and catalase) under stressful settings. It also supports nerve growth and new pathways via increasing levels of brain-derived neurotrophic factor (BDNF).

Clinically, supplementation with L-theanine has been shown to have a relaxing effect, reducing anxiety as well as heart rate and blood pressure in acute stressful events and during mentally challenging tasks.

 L-theanine has been shown to reduce subjective experiences of stress and salivary α-amylase activity, a marker of sympathetic nervous system activity and the “fight or flight” response, during academic challenges. 

At a dosage of 200 mg daily, L-theanine has been shown to significantly reduce emotional symptoms of premenstrual syndrome, including irritability, anger, mood swings, and crying. 

In children with ADHD, L-theanine has also been shown to improve aspects of sleep quality and has been studied and found safe to be used for this purpose at doses of 200 mg twice daily. 

L-theanine continues to be studied for the impacts it may have on learning and memory, attention, mood, and even other mental health conditions such as schizophrenia.

Orally, L-theanine has been shown to be well tolerated.