L-theanine is an amino acid derivative found in tea from the Camellia sinensis plant. Concentration in various teas depends on the processing of the tea. L-theanine is often included in energy or weight loss supplements for its ability to behave much like caffeine in the body, improving alertness and energy; however, unlike caffeine, L-theanine also has a calming effect on the body. For this reason, it is sometimes included in stress relief or calming supplements.
Studies: One study on gophers indicated that L-theanine can improve cognitive function and memory skills shown by an increase of theta wave activity in the brain (National Academy of Sciences)
There are no studies on L-theanine for weight loss, though it may have some thermogenic (increases metabolism) properties just like caffeine.
Quantity needed: If you are a gopher, 25 mg, twice per day, may improve your memory, but I don’t know about weight loss.
