Like all cult beauty products worthy of throwing $20 (or more) at, I heard about spraying French water on my face via word-of-mouth and researched it further by perusing beauty blogs. On a vacation in Paris a couple years ago, friends had urged me to go to “that famous pharmacy in Saint Germain” to pick up “all the best stuff.” City Pharma, as I remember it, was indeed a crazy place. People rave about it on Yelp; your local friend will politely pass on going in with you. As New York magazine put it, “Every day of the year at this establishment is like Black Friday, from the moment the doors open until the moment they close.”

Since then, I’ve found myself continuing to purchase the one product I came out of City Pharma clutching that day: a can of thermal-spring-water spray. The water inside these cans come from thermal springs in various parts of France; the brands themselves are often named after the city where these mythical healing pools are located—Avene, La Roche Posay, and Vichy.

Spraying water on my face became somewhat addictive. At first it was just the desire for softer skin, but as winter came and a particularly bad case of rosacea hit my cheeks, I kept the spray in my bathroom, at my desk at work, even a small bottle in my purse. After all, I need hydration, and water is supposed to hydrate. I survived friends laughing at me, and others shrugging me off with “you do you” empowerment. Sometimes, I felt like Zoolander asking Tyrese to spray Evian on him during the walk-off, which is to say pretty silly. I’d spray the mist onto my face, leave it for three minutes as directed, and pat it dry. The bottle also said to “use as often as necessary,” which when my skin was irritated and red that winter, meant all the time.

That winter I also tried several prescription creams for my rosacea, and while they helped in the short run, they caused flare-ups over time. At that point, I’d somehow bought into the idea that spraying French water on my face would help. After all, I’d installed a water filter in my shower and started using a humidifier. The more moisture in the air surrounding my skin, the better, right?

But just like the idea that drinking water is good for your skin, this just might not be true. The practice of spraying thermal water on one’s skin likely comes from an ancient Greek tradition called balneotherapy, or bathing in mineral water baths as a dermatologic treatment. These days, the practice blurs the lines between a spa experience and an alternative medical treatment. The science behind spraying thermal water is mostly backed by studies done by the French companies that sell the products. One 2015 study by a group of German researchers at Goethe University in Frankfurt found that spa waters can help in the treatment of chronic inflammatory skin diseases, but it called for further study. “A general problem of studies dealing with spa waters is that most of these studies are initiated by the spa water manufacturers themselves. Independent scientific investigations are rare and necessary to providing a more solid basis to evaluate spa water-mediated effects … Particularly in the last few decades, the French cosmetic industry has marketed thermal spa waters as cosmeceuticals, requiring some effort to prove cellular effects.”

In fact, the sprays can actually backfire. “It does help with moisture, but it's important not to apply it too many times during the day because too much water can be drying. It's a very fine line, unlike the creams and moisturizers that are emollients and are a bit thicker, with thermal water, it's important not to spray it multiple times because it can create the opposite effect,” explains Emma Guttman, a dermatologist at Mount Sinai Hospital in New York and the director of the Center of Excellence in Eczema. "If the body is in too much contact with water, it actually dries. It's like washing your hands multiple times during the day—your hands will be very dry."

Another dermatologist, Annie Chiu at The Derm Institute, a dermatology practice in Redondo Beach, California, said that while the potential healing powers of thermal-spring water are understudied, there might be benefits. “Thermal-spring waters usually have a unique mix of minerals that contribute to the overall health of what we call the skin biome. The skin essentially has a complex ecosystem with a delicate balance of minerals, fatty acids, and even good bacteria,” explained Chiu. “If you wash your face with harsher soaps or in general have more inflammation on your skin due to a skin condition like acne or rosacea, a thermal-water spray could theoretically rebalance this micro environment for a healthier skin barrier.”

This theoretical is not the only reason I kept on spraying. If I’m being honest, I know part of the reason I started spraying water on my face in the first place comes from a long ingrained desire to be like the myth of the sophisticated French woman, the one who never gets fat, who doesn’t wash her face with regular water, and who smokes cigarettes but still looks flawless. The beauty sector in France bets big on this dream: French products are a $17 billion industry, according to one industry estimate. The spray is an easy way for American women to emulate French traditions, which are supposedly much better than our own. And another justification also helps: It’s just water; it can’t hurt.