1cP-LSD, or 1-CPA-LSD, also known as 1-cyclopropanoyl-LSD, is a psychedelic drug of the lysergamide family and an acylated derivative of lysergic acid diethylamide (LSD) which has been sold as a designer drug. It is a prodrug of LSD.

1cP-LSD has been used in the form of blotter tabs containing 100 μg 1cP-LSD free base and pellets containing 150 μg 1cP-LSD hemitartrate.

1cP-LSD is a prodrug of LSD. It has been found to produce psychedelic-like effects, specifically the head-twitch response, in rodents with similar potency as 1P-LSD.

Related compounds include 1B-LSD, 1DD-LSD, 1P-LSD, 1V-LSD, ALD-52 (1A-LSD), 1cP-AL-LAD, AL-LAD, ETH-LAD, 1P-ETH-LAD, PRO-LAD, LSM-775, and LSZ, among others.

1cP-LSD was first synthesized as a legal LSD alternative by Lizard Labs, a Netherlands based research chemical laboratory.^{[citation needed]}

Sweden's public health agency suggested classifying 1cP-LSD as a dangerous substance on 18 December 2019 and later classified it as such on 22 April 2021.

1cP-LSD has been investigated as a potential treatment for anxiety in dogs.