Amino acid
L-Theanine
L-theanine is an amino acid found in tea leaves that is not used to build proteins. Black and green tea contain it alongside caffeine.
Also listed as Theanine
How much is in a cup of tea?
In one laboratory analysis, a 200 mL cup of black tea averaged 24.2 mg of theanine, compared with 7.9 mg for green tea. These were averages for the teas and preparation method tested, not fixed values for every cup. Brewing time changed extraction. 1