... Top Quality√ First domestic L-Theanine manufacturer through USP auditAbout Us:Zhejiang Tianrui Chemical CO., Ltd., situated in south ... D, production, sales and technical services of L-Theanine, L-Pyroglutamic acid, L-Glutamic acid etc. Our plant is designed, ... establishing brand advantage.Leading TechnologyWe specialized in production of L-Theanine for many years, with competitive advantages in ...