Xylometazoline-d 4 hydrochloride is deuterated labeled Xylometazoline hydrochloride. Xylometazoline hydrochloride is an α-adrenergic receptor agonist ( K i =0.05-1.7 μM). Xylometazoline hydrochloride can constrict nasal blood vessels and increase nasal airflow. Xylometazoline hydrochloride can be used in nose stuffiness and runny nose research.