Glossary
HHC (hexahydrocannabinol)
Updated:
Hexahydrocannabinol, or HHC, is a hydrogenated form of THC. It is intoxicating. Commercial HHC is made from hemp CBD in 2 steps: conversion to THC, then hydrogenation. It reached the market in 2021 and is not a cannabinoid the plant produces in meaningful amounts.
HHC was first synthesized and described about 80 years ago, but it only appeared in consumer products in 2021 (Ujvary 2024). It is THC with hydrogen added across the ring double bond, which makes it more stable to heat and oxidation.
Current production starts with hemp-derived CBD. The CBD is cyclized into a mixture of delta-8 and delta-9 THC, then hydrogenated over a metal catalyst. The result is a mix of two epimers, (9R)-HHC and (9S)-HHC, and the 9R form carries most of the THC-like activity (Ujvary 2024). A 2024 review found that human pharmacology and metabolism of HHC had not yet been studied in controlled trials.
Because HHC is manufactured rather than extracted, it falls within the exclusion for cannabinoids synthesized or manufactured outside the plant in the amended federal hemp definition (7 U.S.C. 1639o). The exclusion for cannabinoids the plant cannot naturally produce applies from November 12, 2026, and the rest from December 11, 2026.
UPS prohibits shipment of any synthetic or lab-made cannabinoid compound (UPS). A certificate of analysis for HHC should list both epimers separately.
Sources
- Hexahydrocannabinol and closely related semi-synthetic cannabinoids: A comprehensive review (Drug Test Anal, 2024) PubMed (accessed 2026-10-13)
- 7 U.S.C. 1639o, Definitions (hemp) Cornell Legal Information Institute (accessed 2026-10-13)
- Shipping Hemp and Hemp-Derivatives UPS (accessed 2026-10-13)