3-Iodotyrosine is an inhibitor of tyrosine hydroxylase (Ki = 0.39 µM) and an intermediate in the synthesis of thyroid hormones.{51108,51109} It has been incorporated into proteins as a non-natural amino acid for use as a label to detect protein-protein interactions.{51110} 3-Iodotyrosine induces the formation of a-synuclein aggregates and tyrosine hydroxylase-positive inclusions in primary substantia nigra neurons when used at concentrations of 5 and 10 nM.{51111} It induces parkinsonism in mice, reducing locomotor activity and inducing bradykinesia in the open field test when administered at an intrastriatal dose of 10 µM.