... High Specific Rotation, Top Quality√ First domestic L-Theanine manufacturer through USP auditAbout Us:Zhejiang Tianrui Chemical CO., Ltd., ... D, production, sales and technical services of L-Theanine, L-Pyroglutamic acid, L-Glutamic acid etc. Our plant is designed, ... company are ISO22000 and ISO14001 certified. Our products obtained USP, HACCP, KOSHER, HALAL and other international certificates. We ...