Please suggest a brand product name of supplement which contains l theanine.

Suntheanine from...: "suntheanine" is a high-quality patented l-theanine extract that is sold by several different companies including doctor's best, now, natural factors and iti. Any of these will be very high quality. I also often recommend it as part of a combination of relaxing herbs & nutrients, theanine serene with relora from source naturals.