Benztropine-d 3 (mesylate) is the deuterium labeled Benztropine mesylate. Benztropine mesylate (Benzatropine mesylate) is an orally active centrally acting anticholinergic agent that can be used for Parkinson's disease research. Benztropine mesylate is an anti-histamine agent and a dopamine re-uptake inhibitor. Benztropine mesylate is also a human D2 dopamine receptor allosteric antagonist. Benztropine mesylate also has anti-CSCs ( cancer stem cells ) effects.