1-Methyl-2-iodo-LSD (MIL) is a serotonin receptor modulator of the lysergamide family related to lysergic acid diethylamide (LSD). It is the 1-methyl derivative of 2-iodo-LSD (IOL). Extensive metabolism of other 1-methylated lysergamides to their secondary amine derivatives, for instance methysergide (1-methylmethylergometrine) conversion into methylergometrine, has been observed. The properties and effects of MIL in humans are unknown. However, a radiolabeled form of MIL, 1-methyl-2-[<sup>125</sup>I]iodo-LSD ([<sup>125</sup>I]-MIL), as well as the analogue 1-ethyl-2-[<sup>125</sup>I]iodo-LSD ([<sup>125</sup>I]-EIL), have been developed for use as presumably non-hallucinogenic agents in imaging of serotonin receptors. [<sup>125</sup>I]-MIL has much greater selectivity for serotonin 5-HT<sub>2</sub> receptors over dopamine receptors compared to LSD. MIL and [<sup>125</sup>I]-MIL were first described in the scientific literature by Beth J. Hoffman and colleagues by 1985.