Why Does Marijuana Smell Like a Skunk?

It wasn’t long ago that a distinct, sulfury skunk-like odor seeping through your car’s air vents likely meant one thing: a skunk. The mammal is known for its protective, foul-smelling anal spray—was nearby, possibly hit by a car on the highway. 

But over the past 10 years, 18 U.S. states have legalized the sale and use of recreational cannabis (and nearly 40 have some form of medical marijuana). So, it’s just as likely that the “skunky” odor you smell driving through certain areas is coming from a new kind of source: a legal marijuana grow.

Do People Like Their Marijuana to Smell Like a Skunk?

Yes, the cannabis plant is known—and even celebrated—for its distinctive skunky odor. You can find references to the pungent smell in marijuana strain names like Skunkberry, White Super Skunk, and Thelonious Skunk. 

And you can find references to it in lyrics by famous cannabis enthusiasts like the rap trio Cypress Hill.

“Skunk” strains are celebrated for their relaxation-inducing mellow and heavy highs, which many people believe help with mood disorders and anxiety.

But what exactly causes your weed to smell like a skunk? Well, thanks to nearly a century of federal cannabis prohibition making most studies of the plant illegal, we don’t know for sure. But experts do have some ideas—and some of those theories involve one of beer’s most essential ingredients: hops.

Photo: skodonnell via gettyimages.com

The Theories

Terpenes: Terpenes are a relatively new area of focus for most cannabis companies and producers. Terpenes are natural compounds found mostly in plants. They, among other things, produce smells and affect pigment and coloration. And you could say they’re universal: The same terpenes that make a lemon smell like lemon are likely the same terpenes that make your Super Lemon Haze strain smell like a lemon.

There’s a growing understanding within the world of cannabis that the old indica-sativa way of thinking about the effects of the cannabis plant is flawed at best and inaccurate at worst. Instead, “The Entourage Effect” concept is picking up steam. The concept posits that a combination of cannabinoids (CBD, CBG, CBN, THC, etc.) and terpenes are really what cause the unique smell, look, and effect of each cannabis strain.

Another intoxicant that Americans love to consume and sometimes refer to as “skunky” (though usually not in a good way) is beer. And beer is full of hops, which are genetically related to the cannabis plant, falling in the same plant family, called Cannabaceae. 

Experts frequently point to one terpene, myrcene, as having a particularly skunky smell—and it’s found in certain cannabis strains in addition to hops.

“While not all strains with myrcene smell like skunks, it’s a common trait—and one that stoners have grown to love,” explained Herbert Fuego, the columnist for “Ask a Stoner,” a feature in Denver’s Westword alt-weekly.

But a growing body of scientific evidence is pointing to a different culprit.

Thiols: Thiols are alcohol-like chemical compounds, except with a sulfur atom in place of the oxygen atom. They’re also the primary cause of a skunk’s defensive stench, according to 1980s research referenced by Discover Magazine.

A 2001 study by the University of Northern Carolina and Belgium’s University of Gent found that 3-MBT, a thiol similar to one emitted by skunks, causes beer to get that skunky persona. That particular thiol was found in the hops used to make the beer.

Thomas H. Shellhammer, a professor of fermentation science at Oregon State University, told Discover that the minute a beer is exposed to ultraviolet light—like sunlight—a chemical reaction occurs that quickly creates the sulfury thiol.

“If you walk outside with a nice yellow beer like a pilsner on a summer day, the change is happening almost immediately,” Shellhammer told Discover.

And the thiol theory got some serious backing in a recent peer-reviewed study by California-based terpene research and production company Abstrax Tech.

Using a technology called 2-Dimensional gas chromatography (or 2DGC) the researchers found “key volatile sulfur compounds (VSCs)—organic compounds containing sulfur” and thiols as the primary cause of the skunky smell in cannabis, according to a press release announcing the findings. The study says these compounds are actually similar to VSCs found in garlic.

“I have suspected for years now that we were missing something in our understanding of this plant,” study co-author and cannabis industry veteran Josh Del Rosso said in the release. “Although terpenes have been hailed as the major source of the pungent scent of cannabis, we now know that it is this new class of VSCs.”

So whether it’s terpenes, thiols, key volatile sulfur compounds or something else yet to be discovered, the age-old question of, “Why does my weed smell like a skunk?” has a growing body of science to be explored.