Derivation of a Health-Based Guidance Value for Δ8-tetrahydrocannabinol (Δ8-THC) and Its Occurrence in Food.

Abstract 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.