L-Theanine is a dietary supplement in tablet form containing L-theanine , a non-protein amino acid naturally found in green tea leaves. This formula is suitable as a dietary supplement for adults. Key Features of SFD L-Theanine 200 mg of L-theanine in one tablet. Additionally 100 mg of inulin. 180 servings per package. Simple composition, convenient portioning. L-theanine is a biologically active non-protein amino acid that occurs naturally in tea leaves. It constitutes approximately 1–2.5% of the dry weight of the leaves and, due to its chemical structure, is similar to .