2-(Cyclohex-1-en-1-yl-d9)-2-(4-methoxyphenyl)acetonitrile is an impurity of Venlafaxine-d10 Hydrochloride, the labeled analogue of D,L-Venlafaxine, Hydrochloride (V120000), a selective serotonin noradrenaline reuptake inhibitor. Used as an antidepressant.