1T-LSD, also known as 1-(thiophene-2-carbonyl)-LSD or as SYN-L-021, is an acylated derivative of lysergic acid diethylamide (LSD), which has been sold as a designer drug. It was first identified in Japan in 2023 on blotter paper misrepresented as containing 1D-LSD, but which on analysis was determined to contain 1T-LSD instead. It was also detected in Germany around the same time.
A 150üg dose of 1T-LSD is said to be equivalent to 100üg LSD. Doses of 87 to 100üg 1T-LSD have been encountered in blotter tabs.
Analogues of 1T-LSD include ALD-52 (1A-LSD), 1P-LSD, 1B-LSD, 1V-LSD, 1DD-LSD, and 1T-AL-LAD, among others.
1T-LSD is not a controlled substance in Canada as of 2025.
1T-LSD is not an explicitly controlled substance in the United States. However, it could be considered a controlled substance under the Federal Analogue Act if intended for human consumption.