Lophophine (MMDPEA or 3-methoxy-4,5-methylenedioxyphenethylamine) is a putative psychedelic and entactogen drug of the methylenedioxyphenethylamine class.

Alexander Shulgin originally suggested that lophophine may be a natural constituent of peyote (Lophophora williamsii) due to it being the only logical chemical intermediate for the biosynthesis of several tetrahydroisoquinolines known to be present in this cactus species.

[1] Subsequently, lophophine was indeed shown to be a minor component of both peyote and San Pedro cactus.

[2] Shulgin reports that lophophine is active in the dosage range of 150–250 mg.

He states that at these doses, lophophine has some similarity to mescaline in action, in producing a peaceful elevation of mood, euphoria, and mild enhancement of visual perception, but without the generation of closed-eye mental imagery.