L-Theanine (γ-glutamylethylamide), is a unique free amino acid, non-protein based, water-soluble bioactive component of tea. It is an analog of glutamate with neuroprotective and antidepressant properties. The intake of l-theanine affects brain functions by relieving stress disorders, improving mood, and maintaining normal sleep. l-theanine can potentially reduce cognitive impairment as it suppresses delayed neuronal cell death in the hippocampal Cornu Ammonis 1 area after transient ischemia, reduces excitotoxicity by suppressing the extracellular release of glutamate through inhibition of the glutamine transporter, and promotes neurogenesis.  

 It has several other health benefits, such as antioxidant scavenging reactive oxygen species (ROS), anti-inflammatory, anti-cancer, metabolic regulatory, cardiovascular protective, liver and kidney protective, and immune regulatory effects.