In the 1940s, chemist Roger Adams discovered HHC by adding hydrogen to the THC molecule through a process called hydrogenation. This altered its physical properties and was first documented in a 1947 patent.
Hydrogenation transforms the structure of delta 9 THC, replacing a double bond with two hydrogen atoms, making the molecule more stable and resistant to thermo-oxidative breakdown. This results in a longer shelf life and increased resistance to damage from UV light and heat, as noted by chemist Mark Scialdone.
Various methods exist for HHC production. Older approaches involved synthetic gastric juices converting THC to HHC. Modern methods use a terpene called citronellal or a hydrogenation process with catalysts like palladium. An intriguing alternative involves converting CBD (cannabidiol) to HHC using synthetic gastric juices, producing two HHC isomers (9α-OH-HHC and 8-OH-iso-HHC) and delta 9 THC (which must be separated and eliminated from the final product).