[3][4] It is a non-hallucinogenic serotonin 5-HT2A receptor partial agonist, as well as acting at other targets, with psychoplastogenic and antidepressant-like effects in animals.

[3] 2-Bromo-LSD was found to be inactive as a psychedelic and so was comparatively little researched for many years, although its similar behaviour in the body made it useful for radiolabelling studies.

[3][9] Unlike LSD, 2-bromo-LSD fails to produce the head-twitch response, a behavioural proxy of psychedelic effects, in animals.

It had been thought that this specific therapeutic action against cluster headaches was limited to hallucinogenic drugs of this type, and would always present a major barrier to their clinical use.

Some isolated incidents of hallucinogenic responses with 2-bromo-LSD have been reported, but as with other non-hallucinogenic LSD analogs such as lisuride, this appears to be a rare side effect occurring only in individuals with an as yet unexplained susceptibility to this reaction.