If you’re like the many out there looking to up their magnesium intake, then you’re most likely already toying with the idea of including a magnesium body spray somewhere in your routine. And how can you not be? With promises of easier sleep and less stress just one spray away, a product hasn’t sounded more enticing since ear seeding to help with cortisol face.

Magnesium body sprays are topical solutions that contain—you guessed it—magnesium. They aim to ease muscle tension, help you sleep better, and add relaxation to your life by spraying the mineral through the skin. “They’re positioned as a way to increase magnesium levels in the body without oral supplementation,” explains Krupa Koestline, founder and chief cosmetic chemist of KKT Labs.

Koestline goes on to explain that they are mostly made of magnesium chloride hexahydrate which which you’ll most likely see as marketed as “magnesium oil,” dissolved in water. Most sprays are made with 20 to 35% of this magnesium chloride solution, and some formulators may include humectants like glycerin and other soothing agents to offset the dryness and stickiness that the magnesium oil might have.

We do seem to be at a magnesium deficiency. Studies show that 2.5 to 15% of the US population is currently not getting enough of the mineral. Amanda Kahn, MD, board-certified internist and longevity specialist, says that a magnesium deficiency is common and lists modern diets being low in magnesium-rich foods, chronic stress, and medications such as birth control pills may all play a role in that. That’s where magnesium body sprays are supposed to come in handy. But can you actually spray your way to better sleep?

Do they work?

They do work—to a certain extent. Dr. Khan says that while some magnesium can be absorbed, the rate at which magnesium is being absorbed is inconsistent, making it hard to determine if it is working the way it is marketed. The skin is also a strong barrier, and Koestline adds that magnesium ions are relatively large and highly hydrated, thus making them less permeable to get through the outer layer of the skin. There are small studies that show that topical use of magnesium can increase magnesium levels in the epidermis, but more studies need to be done to see if it does as much as oral supplements.

“From a scientific standpoint, they function more as a mineral salt spray with local sensory effects (cooling, soothing, hydrating) rather than a proven systemic delivery mechanism,” says Koestline.

The Best Way to Use a Magnesium Spray

You don’t have to write off magnesium sprays completely, though. The best way to use one is in addition to any oral magnesium intake. “Sprays are a nice adjunct, not a replacement,” she says. “My recommendation is to use oral magnesium as the foundation and use sprays when you want additional muscle relaxation or a calming ritual at night.”