Do HHC Metabolites Always Prove HHC Consumption? A THC Metabolism Study
Some HHC-related metabolites may arise from THC metabolism, so their detection does not invariably establish separate HHC consumption. Research combining forensic whole-blood samples with human liver experiments provides a specific reason to examine the pathway.
Two complementary forms of evidence
Falck Jørgensen and colleagues tested whole blood from 308 forensic traffic cases, including 222 positive for delta-9 THC. HHC-COOH and 11-hydroxy-HHC were detected in subsets of those THC-positive cases.
The researchers also incubated THC and selected metabolites with pooled human liver microsomes. Those experiments supplied controlled biochemical evidence that the HHC-related products could form from the THC pathway.
Parent HHC was not demonstrated as the intermediate
HHC-COOH formed in incubations starting with THC or 11-hydroxy-THC. The hydroxylated HHC metabolite appeared in the 11-hydroxy-THC incubation. Parent HHC was not detected in the incubations.
That pattern argues against casually describing the experiment as proof that THC is simply converted into measurable parent HHC. The authors proposed reduction at a later metabolic stage, followed by further oxidation.
What remains uncertain in a case?
The forensic samples were not a controlled administration cohort with independently verified exposure histories. Their co-occurrence pattern alone cannot exclude separate HHC use in every individual. Laboratory formation establishes a possible source, rather than uniquely identifying the source of any particular sample.
Source attribution should consider parent compounds, the complete metabolite pattern, analytical identification criteria, and independently documented exposure. Neither an HHC-related metabolite nor parent THC establishes functional impairment. The study changes the specificity of a consumption inference; it does not provide a new behavioral threshold.
Related reading: why urine and blood results are not interchangeable.
Primary research
Christian Falck Jørgensen; Brian Schou Rasmussen; Kristian Linnet; Ragnar Thomsen. Evidence of 11-Hydroxy-hexahydrocannabinol and 11-Nor-9-carboxy-hexahydrocannabinol as Novel Human Metabolites of Δ9-Tetrahydrocannabinol. Metabolites (2023). DOI: 10.3390/metabo13121169.
