(αR)-3-Hydroxy-α-[[methyl-d3-(phenylmethyl)amino]methyl]-benzenemethanol is labelled (αR)-3-Hydroxy-α-[[methyl(phenylmethyl)amino]methyl]-benzenemethanol (H947740), a derivative of (R)-Phenylephrine (P320640, HCl salt) which is an α-Adrenergic agonist.