Theanine, also known as L-γ-glutamylethylamide and N⁵-ethyl-L-glutamine, is an amino acid analogue of the proteinogenic amino acids L-L-glutamate and L-glutamine. It is found in particular plant and fungal species and should not be confused with another amino acid called threonine. Theanine is thought to produces calming effects in the brain and nervous system by increasing levels of serotonin and dopamine.
Theanine is related to glutamine and can cross the blood-brain barrier. Because of this, theanine has psychoactive properties. It has been shown to reduce mental and physical stress and may produce feelings of relaxation and improve cognition and mood. It also helps to keep the body alert and attentive reducing stress levels and may help to prevent cancer and cardiovascular problems.
Natural sources of theanine in alphabetical order
- Basidiomycete mushrooms
- Tea leaves from the Camellia sinensis plant, including green, black, white, and oolong teas
NOTE: Green tea is the highest natural source of theanine.
Related subjects