Delta-8 THC

Δ⁸-THC is a positional isomer of Δ⁹-THC in which the double bond sits between C8 and C9 rather than C9 and C10, conferring greater thermodynamic stability and slower oxidative degradation. Pharmacologically it is a CB1 partial agonist with roughly two-thirds the affinity and potency of Δ⁹-THC in most assays (Razdan, 1986, Pharmacological Reviews 38:75; Hollister & Gillespie, 1973). Δ⁸-THC occurs only in trace amounts in fresh cannabis; nearly all Δ⁸-THC in US consumer products is semi-synthetic, produced by acid-catalyzed isomerization of hemp-derived CBD — a reaction that generates poorly characterized byproducts, including olivetol derivatives, Δ⁹ and iso-THC isomers, and chlorinated impurities when HCl is used (Kiselak et al., 2020, Forensic Science International 308:110173). The FDA has issued consumer warnings; several states restrict it. ⚠️ Regulatory status and safety profile remain contested. → See also: Delta-9 THC, CBD, Synthetic cannabinoid.