Very high affinity and selective melatonin agonist (Ki values are 14 and 112 pM for human MT1 and MT2, respectively). Selective for human MT1 and MT2 over hamster MT3 and a range of other targets including benzodiazepine, opiate and dopamine receptors, ion channels and transporters. Accelerates return to normal circadian rhythm in rats after phase shift, without affecting learning and memory. Also reduces infarct size in rat heart in vitro post ischemia-reperfusion. Purity 98%. MW (observed): 259.34