Derivation of a health‐based guidance value for Δ‐tetrahydrocannabinol (Δ‐THC) and its occurrence in food

The European Food Safety Authority (EFSA) was asked to deliver a scientific opinion on the derivation of a health‐based guidance value (HBGV) for Δ⁸‐tetrahydrocannabinol (Δ⁸‐THC) in food with an assessment of the occurrence of Δ⁸‐THC and the co‐occurrence with Δ⁹‐THC in hemp and hemp‐derived products. Data from a clinical study were used to inform on the relative potency between Δ⁹‐THC and Δ⁸‐THC. The point estimate of the relative potency (ratio Δ⁹‐THC/Δ⁸‐THC) was in the range between 1 and 1.4, with 95% confidence between 0.97 and 1.63. Based on this range, the CONTAM Panel, using a conservative approach, set a relative potency factor of one for Δ⁸‐THC. The CONTAM Panel had previously set an acute reference dose (ARfD) of 1 μg/kg body weight for Δ⁹‐THC derived from adverse effects on human central nervous system (CNS). Given the similarity in the effects and the mode of action between Δ⁸‐THC and Δ⁹‐THC, the Panel considered that the established ARfD can be considered as a group ARfD for the sum of Δ⁸‐ and Δ⁹ THC. Regarding the occurrence of Δ⁸‐THC, the majority of samples were left censored, in particular for hemp infusion leaves, hemp seed oil and hemp seeds (96%-99%). Highest detection rates and levels were found in the categories 'Sugar and similar, confectionery and water‐based sweet desserts' and 'Products for non‐standard diets, food imitates and food supplements'. Of 1145 samples, both substances were detected together in only 96 samples. If the two substances are produced naturally, a Δ⁸‐THC to Δ⁹‐THC ratio below 1 is expected; however, many of the samples, positive for Δ⁸‐THC, were above this ratio indicating either addition of semi‐synthetic Δ⁸‐THC, formation during processing or enrichment of the natural Δ⁸‐THC.