Doctor?s Best L-Theanine with Suntheanineis an amino acid that promotes a relaxed state without drowsiness, eases stress and everyday tension, and promotes a positive mood and alertness.*The formula uses L-Theanine with Suntheanine, a patented form of the amino acid L-theanine.L-theanine is an amino acid found in green tea that is responsible for the relaxation-inducing effect of tea consumption. * 77525SKU 753950001978