Cepentil, or Tsepentil, also known as N-cyclopentyllysergamide (NCPe-LA) or as lysergic acid cyclopentylamide (LCyP), is an analogue of LSD developed in the former Soviet Union which acts as an antagonist at serotonin receptors. It does not produce hallucinogen-like effects in animal studies, instead being described as an "energizer" by contemporary sources, suggesting an action similar to the antidementia drug hydergine, however the pharmacology of cepentil has not been studied with modern techniques.