Synthetic cannabinoids are chemicals made in a laboratory setting. Unlike phytocannabinoids and endocannabinoids, they are manmade and do not occur in nature. These substances are engineered to target the receptors of the endocannabinoid system to produce specific effects.
Some synthetic cannabinoids exert proven therapeutic actions and work in a similar way to cannabinoids found in the cannabis plant and the human body. For example, researchers developed dronabinol—the active component of Marinol—to target the CB1 receptor much like the phytocannabinoid THC.
Nabilone—another synthetic cannabinoid—also mimics the action of THC inside the body. The chemical binds to the CB1 receptor and has been used in therapeutic settings to ease an upset stomach, among other applications.
Although the synthetic cannabinoids above display some therapeutic potential, others are much more dangerous. Hundreds of different synthetic cannabinoids exist, and many of them produce distinct effects. These chemicals are often made into makeshift concoctions and distributed on the black market under names such as “K2” and “spice”.
Unlike THC, which only partially activates cannabinoid receptors, some synthetic cannabinoids fully activate them, and are known to be up to 200 times more potent than THC at these sites.
This mechanism may cause dangerous side effects in some instances. Synthetic cannabinoids are associated with higher rates of toxicity, hospital admissions, irritation, confusion, acute kidney injury, etc.
In comparison, phytocannabinoids feature a much more impressive and consistent safety profile. Even when synthetic cannabinoids are administered in therapeutic settings, they are much more unpredictable than their natural counterparts.
Scientists carefully create FDA-approved synthetic cannabinoids such as dronabinol in a laboratory setting. The compound contains the THC molecule and is suspended in sesame seed oil, then placed into capsules.
However, other synthetic cannabinoids are often crafted in underground laboratories and distributed illegally to willing customers. The synthesis of these chemicals all started with organic chemistry professor John William Huffman. Starting in 1984, he and his team synthesised over 400 synthetic cannabinoids during their work at Clemson University, South Carolina.
Their original intention was to develop chemical tools to study the endocannabinoid system. However, two of these molecules appeared on the German black market in the late 2000s.
These molecules are produced in a lab and diluted into a base of acetone, then sprayed onto various forms of dried plant matter to replicate the format of herbal cannabis.
This careless manufacturing process can lead to various errors, including exceptionally potent and dangerous batches of the drug.
Hundreds of synthetic cannabinoids exist. Some of them—such as dronabinol—serve legitimate therapeutic or research purposes, while others are abused and come with dangerous side effects. Not only are naturally occurring cannabinoids much safer, but emerging research also suggests that full-spectrum cannabis extracts may be more effective than single isolated molecules.
 Castaneto, M. S., Gorelick, D. A., Desrosiers, N. A., Hartman, R. L., Pirard, S., & Huestis, M. A. (2014). Synthetic cannabinoids: Epidemiology, pharmacodynamics, and clinical implications. Drug and Alcohol Dependence, 144, 12–41. https://doi.org/10.1016/j.drugalcdep.2014.08.005 [Source]
 Mills, B., Yepes, A., & Nugent, K. (2015). Synthetic Cannabinoids. The American Journal of the Medical Sciences, 350(1), 59–62. https://doi.org/10.1097/maj.0000000000000466 [Source]