In these divided times, one truth seldom disputed is that animal secretions are gross. No matter how lovely the pup, dog slobber is plainly nasty. The yellow fluid that seeps from scared ladybug legs has befouled too many picnics to count. Bird shit is a windshield’s scourge. As a general statement of fact, people do not usually relish or seek out the presence of animal goop on or in their bodies.

There are exceptions, of course. Squid ink is a culinary delicacy. Elite perfumeries covet the ambergris secreted by sperm whales, which is treasured for its irreproducible musk. Everyone loves honey, which is basically bee vomit. Over the past decade, another special case has risen from a cult cosmetic treatment to a standard component of skin care routines, first gaining popularity in South Korea in the 2000s and then moving into the rest of the world. Snail slime, the mucus oozing from a gland on a snail’s foot, is now a commonplace ingredient for facial ointments, masks, and treatments. “Cover Your Face In Snail Slime,” cosmetics website Into the Gloss implored readers in 2014. Both CNN and Bloomberg called it a “craze” in 2017. Drew Barrymore and Katie Holmes are reportedly fans.

I am another willing slime devotee. Every morning, two dabs of an inexpensive Korean snail “essence” go on my cheeks and forehead. Once a week, I sit on my couch looking like a serial killer with a slimy snail extract mask draped on my face. As with all of my vanity-soothing rituals, I’ve never been sure how well these products work, only that they make me feel like I’m taking a proactive step toward better skin. The companies that sell these products often make sweeping claims about their efficacy — snail slime helps regenerate cells! It’s anti-acne and anti-aging! — but marketing claims and actual research-backed evidence are frequently two very different things.

Dr. Joshua Zeichner, the director of cosmetic and clinical research for Mount Sinai Hospital’s Department of Dermatology, says that mollusk goo is more than empty hype. “Snail slime has been shown to have antioxidant properties, as well as the ability to stimulate collagen production and enhance wound healing. It is also rich in hyaluronic acid, which is a humectant ingredient that pulls in hydration to the outer skin layer,” Zeichner told me by email. “In fact, there is data showing that creams containing snail slime actually help improve the appearance of fine lines and wrinkles and the sun damage.”

But Zeichner cautioned against throwing lots of money at anything with the word “snail” on it. “Many snail slime products or snail slime facials may be very pricey,” Zeichner said. “While there is little downside [to applying snail slime], we need more data to prove whether it is any more effective than traditional moisturizing or anti-aging products.”

Cosmetic scientist Colin Sanders expressed similar ambivalence. “It works okay,” he told me over email. “I wouldn’t particularly recommend it, as I think there are better options out there.” Sanders has colorfully described the limits of snail slime on his cosmetic science blog, Colin’s Beauty Pages, where he explains that the slime is composed of proteins and polysaccharides, which dissolve in water. “If you then dry them, they shrink back again,” he wrote, explaining that the ingredients tighten the skin as they dry, and may occasionally help reduce fine lines caused by dryness. “If there were some reason to believe that snail slime was more effective than other polymers at giving the kind of tightening of the skin that people want, it might make a lot of sense. But to be honest, there isn’t really. You could make just as good a case for wallpaper paste.” (He then issued a warning that wallpaper paste is unsafe to apply to skin.)

The cosmetics world is underregulated, and snail slime, like many “miracle” ingredients, does not have a sizable trail of peer-reviewed evidence. A small 2013 study in the Journal of Drugs in Dermatology did find that a serum containing 40 percent snail mucin did improve fine lines and wrinkles on a test group of 25 people over a 12-week period, but it was funded by pharmaceutical company Biopelle, which just so happens to sell snail serum. There are few larger-scale studies. Even its origin story is difficult to pin down. Bruno Bonnemain, who works as a scientific adviser for the French pharmaceutical company Guerbet, wrote a history of the substance in 2005, citing ancient figures like Hippocrates and Pliny as advocates of the healing properties of land snails. According to Bonnemain, the 18th-century French medical reference book Universal Pharmacopoeia featured a passage on crushing up snails into a concoction used for “skin redness,” and that another French medical reference book, Dorvault, discussed therapeutic snail-based ointments as recently as 1945. (It should be noted that Bonnemain published this work in Evidence Based Complementary and Alternative Medicine, an academic journal that has been disavowed by one of its cofounders as “useless rubbish.”) Chilean snail slime purveyors, meanwhile, claim that the ointment was discovered 30 years ago, on a mountain farm, an accidental eureka after workers noticed their hands growing smoother as they handled the mollusks.

While its exact backstory is still unknown, the surge in interest in snail slime, and accompanying surge in the industry surrounding it, is apparent. As Korean cosmetics companies like Skin Food and Missha have expanded into Western markets, snail slime products have been some of the most popular exports. (The BBC called snail slime one of the South Korean skin care industry’s “key ingredients” in 2016.) A spa in Tokyo debuted a treatment in which living snails were strategically placed on customers’ faces in 2013. In Thailand, Chiang Mai’s Snail Spa opened in 2015. In Italy, the boom in demand for snail products has resulted in a 325 percent increase in snail farming over the past two decades. A plastic surgeon in Manhattan, Dr. Matthew Schulman, now offers an “EscarGlow” facial, charging $375 to apply snail slime after creating tiny abrasions in the face with microneedles. “Our snail extract is gathered from a specialized snail farm in Spain. No snails are harmed during this process. In fact, the snails are meticulously cared for and receive daily ‘showers’ with fresh water and a feast of fresh fruits and vegetables,” Schulman told me by email.

People in the snail slime business are quick to point out that modern slime collecting does not require the killing or injuring of snails. While snail farmers originally extracted the goo by stimulating the creatures with vinegar or salt, which killed them, new methods of raising the mollusks are far less cruel. Italy’s International Heliciculture Association patented a slime-extracting device designed to cause snails minimal discomfort, known as the Muller One. “It is essentially a spa for snails,” Simone Sampo, the organization’s president, told The Telegraph in 2017. “We raise them naturally, feed them only vegetable matter and then extract the slime with water that contains ozone, which kills all the bacteria. The snails are not harmed.” (PETA still disapproves of snail slime products.)

While snail slime products are often marketed to display their active ingredients, packaged slickly as luxury items, there’s a charm to repurposing a natural byproduct, an unexpected hippie appeal, a whiff of a thrifty and intuitive approach to beauty. Using the debris from snail trails as a fancy moisturizer seems like the Goop version of eating the whole animal. As wellness trends continue to tilt toward an idealized version of “clean” living, it is no surprise that dabbing a tincture collected from what is left behind by small creatures has secured a vogue.

So far, though, there are no organic farm-to-vanity snail outfits driving home the product’s earthy allure for Americans. Snail farming remains a fringe activity in the United States. Long Island–based Peconic Escargot is the first USDA-certified snail farm in the country, but it focuses on raising snails for eating, not beautifying. “We don’t gather the slime for cosmetics. There’s a very expensive machine that’s required to extract the snails slime without killing them — we don’t have it,” head snail wrangler Taylor Knapp told me, noting that the farmers at Peconic do not put snails on their faces. As for the Chilean lore about workers noticing their hands looking nicer, it hasn’t repeated itself stateside. “We handle the snails with our bare hands daily, and haven’t noticed any difference.”

“It seems like a passing fad, to be honest. If it didn’t, we would totally invest in that really expensive machine,” Knapp said. “I’m guessing the world will be moving on to another strange ingredient in a couple of years, if not sooner.”