Δ3-Tetrahydrocannabinol

Δ³-Tetrahydrocannabinol is a synthetic isomer of tetrahydrocannabinol developed during the original research in the 1940s to develop synthetic routes to the natural products Δ⁸-THC and Δ⁹-THC found in the cannabis. While the normal trans configuration of THC is in this case flattened by the double bond, it still has two enantiomers as the 9-methyl group can exist in an or conformation. The enantiomer has similar effects to Δ⁹-THC though with several times lower potency, while the enantiomer is many times less active or inactive, depending on the assay used. It has been identified as a component of vaping liquid products.

Legality

Delta-3-Tetrahydrocannabinol is federally uncontrolled, but due to its similarities with Delta-9-THC it could be prosecuted under the Federal Analogue Act

As of June 25, 2025, the U.S. 8th Circuit Court of Appeals overturned a lower court's injunction, allowing Arkansas to enforce its ban on hemp-derived THC products, including Delta-3 THC. This ruling means that Act 629, which classifies Delta-8, Delta-9, and Delta-10 THC as Schedule VI controlled substances in the state, is now enforceable. Previously, sales of these products had been temporarily permitted due to the injunction.