Butylone (also known as β-keto-N-methylbenzodioxolylbutanamine, βk-MBDB, or B1) is a synthetic entactogen and stimulant belonging to the phenethylamine and cathinone classes. Butylone is the β-keto analogue of MBDB and the substituted methylenedioxy analogue of buphedrone.
As a designer drug, it is frequently sold on the street, often alongside ethylone, as a substitute or counterfeit for MDMA and methylone (collectively referred to as "Molly"), due to the decreasing availability of methylone on the research chemical market.
Despite behavioral and pharmacological similarities between butylone and MDMA, the observed subjective effects of the two substances are not entirely identical.
Butylone has only recently been used in humans and is reported to be less potent than its relatives methylone and ethylone, exhibiting more classic stimulant than entactogenic effects.