25I-NBMD (NBMD-2C-I, Cimbi-29) is a derivative of the phenethylamine hallucinogen 2C-I, discovered in 2006 by a team at Purdue University led by David Nichols. It acts as a potent partial agonist for the 5HT_2A receptor with a Ki of 0.049nM at the human 5HT_2A receptor. The corresponding 4-bromo analogue 25B-NBMD has been used for molecular dynamics studies on the shape of the 5-HT_2A receptor. Common doses are reported to be between 500 Mcg and 1.5 mg. Although the low end of the dose response curve is similar to LSD, being active at 500 Mcg, some reports show 1.5–2.0 mg being a low dose, making it up to four times less active than its nbome counterpart 25I-NBOMe. Because it is a research chemical and has not been on the open market for long, there are very few reports about its use.