Here’s the chemistry behind marijuana’s skunky scent

Cannabis is an herb that has been used for thousands of years, mostly for recreational purposes. But recently its benefits have also become more widely recognized due to the discovery of cannabinoid receptors in various parts of the brain and body.

Here’s the chemistry behind marijuana’s skunky scent



Sulfur chemicals found in cannabis flowers have recently been discovered as the source of the plant’s distinctive stinky stench.

Scientists have now identified the chemicals responsible for marijuana’s pungent odor.

The intoxicating aroma of fresh marijuana is really a concoction of hundreds of aromatic chemicals. According to analytical scientist Iain Oswald of Abstrax Tech, a private firm in Tustin, Calif., that creates terpenes for cannabis products, the most noticeable floral, lemony, and piney overtones originate from a common family of chemicals called terpenes. However, tracing the origins of that distinctive ganja sound has been difficult.

Researchers publish in ACS Omega on November 12 that they are the first to uncover a set of sulfur compounds in cannabis that account for the skunklike odour.

Sulfur, a pungent ingredient present in hops and skunk spray, was suspected by Oswald and his colleagues as the perpetrator. So the researchers began by assessing the skunk factor of flowers taken from over a dozen different Cannabis sativa cultivars on a scale of zero to ten, with ten being the most pungent. Using gas chromatography, mass spectroscopy, and a sulfur chemiluminescence detector, the researchers generated a “chemical fingerprint” of the airborne components that contributed to each cultivar’s distinct aroma.  

The researchers discovered modest levels of various aromatic sulfur compounds hidden in the olfactory profiles of the stinkiest cultivars, as they had predicted. The most prominent was a molecule called prenylthiol, or 3-methyl-2-butene-1-thiol, which is responsible for the infamous taste of “skunked beer.”

According to Amber Wise, an analytical chemist at Medicine Creek Analytics in Fife, Wash., who was not involved in the research, the sulfur compounds have been detected in nature previously, but never in cannabis.

Prenylthiol and several of the other sulfurous suspects in cannabis had structural similarities to molecules found in garlic, which startled Oswald. A little goes a long way, just like these alliaceous analogs.

According to Oswald, these chemicals “may be found in extremely low quantities on the flower yet nevertheless have a significant influence on the scent.” When cannabis flowers attain maturity and throughout the curing process, sulfur compounds are most plentiful.

Smell psychologist Avery Gilbert of Headspace Sensory, a Fort Collins, Colo.-based firm that specializes in measuring the numerous aromas of cannabis, is pleased to see the compounds added to marijuana’s chemical palette. “The range of cannabis odor is incredible,” he adds. “I believe it is superior than wine.”

The finding of prenylthiol in marijuana, according to Gilbert, is the first step toward hiding — or increasing — the plant’s perversely delightful odor.

According to Oswald, prenylthiol has a “polarizing fragrance.” Despite the fact that many people believe it stinks, some cannabis users will pay top price for skunky grass, which some see as a quality sign.

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Frequently Asked Questions

Is there a chemical that smells like skunk?

A: No, there are no chemicals that smell like skunk.

Which terpene is skunky?

A: Citrus terpineol

Does myrcene smell like skunk?

A: The skunk-like odor of myrcene is largely due to the chemical being released when the plant decomposes. Myrcene is a major component in many essential oils, and it can also be found as a terpene in cannabis plants.