1SB-LSD, or 1BS-LSD, also known as 1-TMSBz-LSD or as 1-(4-(trimethylsilyl)benzoyl)-LSD, is a psychedelic drug of the lysergamide family related to lysergic acid diethylamide (LSD). It is thought to be a prodrug of LSD. The drug was encountered online as a novel designer drug in September 2025. 1SB-LSD has been sold in the form of blotter, for instance containing 165μg per tab. It is the derivative of 1Bz-LSD (SYN-L-018) in which there is a 4-trimethylsilyl group on the benzyl ring. 1SB-LSD was first described in the scientific literature by 2026. It is not an explicitly controlled substance in the United States or in Canada.
See also Substituted lysergamide
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