Why does weed smell skunky?

By Emma Stone

Weed has a giveaway odor. It clings to car interiors, lingers in rooms long after the joint has been smoked, and hangs around people who smoke it regularly. Most plants emit a unique smell, but cannabis carries a particularly potent odor, an unmistakable calling card. If there’s one adjective to describe it, it’s skunky.

Many of us remember the day we got our first whiff of weed: For me, it was crossing the university quad late one night during orientation week. That pungent, heady, musky scent assaulted my nostrils like few smells ever have, permanently etching itself into my olfactory memory.

Let’s look at the compounds responsible for weed’s skunky smell, discuss the science of whether they hold unique benefits, and explore some tips for getting rid of weed’s characteristic scent (or at least subduing it).

The source of weed’s skunky scent

Cannabis contains more than 200 cannabinoids, terpenes, and other compounds that contribute to its idiosyncratic scent. However, the chemical basis of weed’s skunk-like smell has long eluded scientists.

“Previously, researchers associated the terpenes known as myrcene, which is present in hops and mangoes, and caryophyllene, found in black pepper, cloves, and cinnamon, as being partly responsible for the skunky smell in cannabis,” said Roger Brown, founder and president of ACS Laboratory.

However, recent landmark research has found that weed’s musky, skunky scent isn’t due to terpenes, but another set of compounds entirely. In 2021, a research team based in California led by Dr. Iain Oswald, PhD, ran a study to find out whether cannabis contained volatile sulfur compounds (VSCs). VSCs are infamous as the compounds that skunks release in their defensive spray.

However, VSCs also play a role in plants with pungent aromas and flavors, including garlic, hops, and durian, which smells so strong it’s actually banned on public transportation in some Southeast Asian countries. Suffice to say, VSCs are powerful odor bombs that can deliver heady aromas and flavors in small amounts.

“[Volatile sulfur compounds] can possess extremely pungent aromas even in very small concentrations—orders of magnitude more pungent than many terpenes,” said Oswald. “A small amount goes a long way when it comes to VSC odors.”

To determine if cannabis contains VSCs, Oswald and his team measured cannabis flower and concentrates using state-of-the-art gas chromatography technologies. Their research uncovered a revelation: Not only does cannabis contain VSCs, but it also contains some that have never been seen in nature. As it turns out, VSCs are largely responsible for weed’s signature stench.

“Even a skunk’s aerosol spray, which can have a similar aroma to cannabis, does not have identical compounds,” explained Oswald. “They are, however, very similar in their chemical structures, hence why they do smell somewhat the same.” The researchers also found that the family of VSCs identified in cannabis are structurally similar to those found in garlic.

One particular VSC—3-methyl-2-butene-1-thiol, or VSC3, as it has come to be known—appears to be influential in shaping the smell of cannabis. It produces an “intense, sulfuric, skunky aroma even in extremely dilute concentrations,” that was also linked with skunky beer, the research team stated in the study.

Oswald and team confirmed that VSC3 is the primary source of the characteristic scent of cannabis, while other VSC compounds further intensify or modulate the aroma.

Moreover, the intense smell isn’t limited to cannabis flower. The team found that cannabis concentrates can retain VSCs through the extraction process and maintain a strong skunky aroma in the final product too.


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