Why Does BO Sometimes Smell Like Weed?
The first time I noticed my BO smelled like weed, I’d just had sex with my girlfriend at the time. She nudged her nose affectionately into my chest. “Hey, you smell like skunk,” she said. I sniffed my underarms—she was right, I did.
Turns out I’m not the only one to have experienced skunky sweat. A Google search revealed several discussions and a Reddit thread where others talked about the phenomenon. Like me, most were baffled. “I smelt my armpit after working out,” Reddit user RIP_MAC_DRE told me. “I had been smoking for maybe two or three years at this point and noticed it smelled like weed; I thought it was pretty funny.”
I stayed up all night trawling the internet for answers. But my search brought up little more than the “top answer” on Yahoo Answers, which was just a description of how to wash. Undeterred, and with nothing better to do, I sought out some of the world’s most eminent biologists and cannabis experts and distracted them from far worthier business in order to discover, once and for all, why my BO sometimes smells like weed.
In an original piece of research for VICE, Dr. Matan Shelomi, a researcher at Germany’s Max Planck Institute for Chemical Ecology, compared studies that broke down cannabis and human sweat into individual chemicals to see if there were any shared compounds. Out of 233 elements and compounds found in marijuana and nearly 100 in human sweat, 11 matched.
“It looks like several of the compounds most strongly associated with the distinct aroma of Mary Jane are also found in gym socks,” Shelomi told me. “Now all we need are a statistically significant number of sensimilla-scented volunteers and an olfactometry lab that’s totally down for whatever.”
Scientific breakthroughs started coming thick and fast. It wasn’t long before Dr. Shelomi realized the cannabis smell probably comes from apocrine sweat as opposed to eccrine sweat. Eccrine sweat is clear and watery, and used to cool the body down, while apocrine sweat glands, clumped mainly around the armpits and genitals, activate during sex and times of stress.
“I remember walking into a [high school] class before giving a presentation and noticing it,” Trent, from Kansas, told me. “Eventually, I figured out that my armpit sweat only smells like weed during or before a stressful situation.”
Dr. Shelomi used this as the basis for a potential hypothesis. “If [this] experience holds true for others, then we can narrow down the source of the pot odor to apocrine secretions.”
Another hypothesis, suggested by Dr. Justin Fischedick, a researcher at the Institute of Biological Chemistry at Washington State University, is that aromatic plant chemicals known as terpenoids and terpenes (“terps,” for short) are present in the sweat. Plants release terps from their leaves and flowers in order to attract pollinators and repel munching insects. “It seems like people who work out are noticing it quite a bit,” Dr. Fischedick told me. “Since [terps] are fat soluble compounds like THC they might be stored in fat cells and get excreted during exercise.”
That covers people who still consume cannabis, but I haven’t smoked any weed in years. Perhaps it’s because, when I was young, I got through enough of it on a daily basis to permanently alter my body odor. “It wouldn’t surprise me if heavy weed intake could alter your smell,” Dr. Shelomi told me. “Others online also report having stopped smoking but still reeking of it.”
I didn’t want to second-guess an expert, but this just seemed impossible to me. The smell, I figured, is more likely caused by dietary plants that share the same terps as cannabis—an idea mooted in the Reddit discussion. “There can be some similarities between the smells,” wrote user LarsHoneytoast. “I think weed, BO, and the lettuce at Subway are all in the same realm of scents.”
I needed to confirm this hypothesis, ideally with the help of someone who isn’t named after a breakfast dish. “The smell of cannabis is produced by its terpenes,” Dr. Franjo Grotenhermen, the executive director of the International Association for Cannabinoid Medicines, told me. “The consumption of other plants with the same terpenes may result in a similar smell.”
Thanks to weed enthusiasts constantly breeding new strains, there are now a host of cannabis varieties that share terps with many other plants; famous strains like Blueberry Cheesecake and Orange Bud are two notable examples. So there are plenty of plants out there that could make sweat smell like skunk.
But if cannabis-smelling terps are so common, why don’t more people smell like London’s Hyde Park on 4/20? Well, BO is not just caused by terps, but also by skin-dwelling bacteria that break down sweat molecules into smaller, volatile compounds that evaporate into smells. Apocrine sweat is also a cocktail of minerals, pheromones, and urea. It seems the skunky smell is down to a particular combination of these composites, making it unusual but not outlandish.
There could be many more people out there who have the right combination of factors to produce the chronic whiff, even if they don’t smoke weed. Naturally, they wouldn’t notice because they’ve never smoked marijuana and so wouldn’t know what to sniff for. Or maybe they know what it smells like but just don’t care enough to spend all night on Google, before bothering multiple scientists about it.
All that can be done for now is to trot out the old scientific banality that “more research needs to be done.” But at least Dr. Fischedick is up for it. “The only way to find out for sure would be to ask volunteers to smoke a bunch of dank, work out, collect some sweat, and measure it in machines,” he told me.
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Body odor that smells like pot is a real phenomenon, according to some of the world's most eminent biologists and cannabis experts.
I’m Paranoid That My Sweat Smells Like Weed
Although science says I’m more right than crazy
With the advent of legal marijuana in California, I’ve rediscovered my love for smoking it — especially before going to the movies. Or when I need to deep clean my apartment. Or if I worked out four times in a week, and therefore, deem myself worthy of a cheat day. Or just to unwind some days when I get home from work.
Or anytime, really.
But with my newfound love for smoking my weed has come another discovery: Smoking weed makes my body odor smell like ganja.
Now, admittedly, I normally smell like a damp sock filled with bleu cheese after going to the gym. But several weeks ago, I noticed a stench that was neither damp sock nor bleu cheese. Nope, it was unmistakably the distinct nodes of weed.
Upon further review, science (almost entirely) proves my nose right: Smoking weed, much like drinking alcohol, does affect one’s body odor.
It’s not the sweat itself, though, that’s causing the stench. Generally speaking, that’s a major misperception — i.e., sweat is odorless; it’s the bajillions of microorganisms on your skin that produces your specific smellprint. Those microorganisms, collectively known as your skin microbiome, literally feed on your sweat, and the byproduct is odor. And since your skin microbiome is affected by the foods, liquids and substances you ingest, it only stands that weed would have a similar effect on your skin, and in turn, your BO.
“We know the things you eat and ingest certainly affect the way your sweat smells,” says Julie Horvath, a professor at North Carolina Central University and an expert in evolutionary genomics. “So if you smoke weed, or ingest it in some other way, it exudes from your body in many different ways, [including through your pores]. I’d presume then [marijuana] would impact your microbes, and therefore, the way you smell.”
Past studies have shown that walking through a smoke-filled room has an observable effect on a person’s microbiome and body odor, Horvath adds. And a 2014 study by researchers in Germany finds that cannabis consumption is detectable through body odor. Some have even posited that the weed BO effect is particularly strong among people who exercise often. The theory, according to Justin Fischedick, a biochemistry researcher at Washington State University, is that THC and other active compounds in marijuana are fat soluble, and stored in your fat cells. Those compounds then get excreted when you’re exercising.
All of which adds up to one simple truth: Weed makes your BO dank.
With the advent of legal marijuana in California, I’ve rediscovered my love for smoking it — especially before going to the movies. Or when I need to deep clean my apartment. Or if I worked out four…