1F-LSD

1F-LSD, also known as 1--LSD, 1--LSD, or SYN-L-005, is a psychedelic drug of the lysergamide family related to lysergic acid diethylamide. It is thought to act as a prodrug of LSD. The drug interacts with serotonin receptors, including the serotonin 5-HT_2A receptor, and produces the head-twitch response in rodents, with about 3-fold lower potency than LSD. It hydrolyzes into LSD in rodents. 1F-LSD was patented in 2024 and was first described in the scientific literature in 2025. It has been encountered as a novel designer drug in Germany and Japan.

Use and effects

Interactions

Chemistry

Analogues

s of 1F-LSD include 1P-LSD, 1cP-LSD, 1B-LSD, 1S-LSD, and 1T-LSD, among others.

Society and culture

Legal status

Canada

1F-LSD is not an explicitly nor implicitly controlled substance in Canada as of 2025.

United States

1F-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.