1B-LSD

1B-LSD (1-butyryl-LSD, also known as 1-butanoyl-LSD) is a synthetic psychedelic of the lysergamide family and an acylated derivative of LSD in which a butyryl (4-carbon) group is attached to the nitrogen at position 1 of the lysergamide core. It is strongly believed to function as a prodrug for LSD itself, with the butyryl group being cleaved by plasma esterases following administration to release pharmacologically active LSD. The subjective effects are therefore expected to be identical or near-identical to LSD, with the primary differences being a slightly delayed onset attributable to the prodrug conversion step.

Community reports consistently describe 1B-LSD as producing an experience indistinguishable from LSD once fully active, with onset typically in the 60–90 minute range and total duration of 8–12 hours. The prodrug conversion ensures that the full LSD pharmacological profile — 5-HT2A partial agonism, dopaminergic modulation, and the broad receptor promiscuity characteristic of LSD — is expressed. Users with extensive LSD experience report that they cannot meaningfully distinguish 1B-LSD's peak effects from conventional LSD at equivalent doses.

1B-LSD appeared in the research chemical market following the example set by 1P-LSD, as vendors and users sought compounds that would produce LSD-like effects while potentially remaining outside the scope of existing drug analog legislation. Like 1P-LSD, 1B-LSD has been used both as a full psychedelic experience compound and in microdosing protocols. The Ehrlich reagent remains essential for confirming the presence of an indole compound and ruling out far more toxic adulterants such as NBOMe compounds.

The risk profile of 1B-LSD is assumed to be essentially identical to LSD, given the prodrug mechanism. However, the exact conversion efficiency and kinetics in humans have not been formally studied for 1B-LSD specifically, introducing a degree of dose uncertainty.