25B-NBOMe

25B-NBOMe (2-(4-bromo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine, also known as NBOMe-2C-B) is a synthetic psychedelic phenethylamine and structural analog of 2C-B, characterized by the addition of an N-(2-methoxybenzyl) group to the terminal amine. It is among the most potent serotonergic psychedelics ever identified, producing full psychedelic effects at doses as low as 250–750 μg. Like all NBOMe compounds, it is only active via sublingual or buccal routes.

25B-NBOMe is associated with multiple confirmed human fatalities, primarily resulting from acute vasoconstriction, hyperthermia, and seizures at high doses. The compound has an unusually narrow therapeutic window — the dose range between perceptible effect and dangerous toxicity is small. This danger is compounded by the fact that blotter potency varies significantly between batches and producers, making accurate dosing without quantitative chemical analysis impossible from a consumer perspective. Multiple death reports describe victims who ingested multiple blotters believing they were LSD.

The compound gained widespread forensic attention in the early 2010s when it appeared on blotter paper sold as LSD, prompting public health warnings from multiple national agencies. It does not produce the characteristic purple-violet color change with Ehrlich reagent (which detects indoles), making reagent testing an effective tool for distinguishing it from genuine LSD. Despite its dangers, it has been used recreationally for its intense visual and cognitive effects at sub-toxic doses by experienced users who carefully control dosing.