Alpha-methyl-L-tyrosine is an L-tyrosine derivative that consists of L-tyrosine bearing an additional methyl substituent at position 2. An inhibitor of the enzyme tyrosine 3-monooxygenase, and consequently of the synthesis of catecholamines. It is used to control the symptoms of excessive sympathetic stimulation in patients with pheochromocytoma. It has a role as an antihypertensive agent and an EC 1.14.16.2 (tyrosine 3-monooxygenase) inhibitor. It is a L-tyrosine derivative and a non-proteinogenic L-alpha-amino acid.