A “detoxifying” skin care treatment, a relaxing act of self-love, a pampering practice for your pet—if TikTok is to be believed, the benefits of an Epsom salt bath are practically endless. But, trendy as they are, the chemical compounds are old as hell: The salts are named after the English town of Epsom where they were discovered in the early 17th century, and they were subsequently extracted and studied for their potential medicinal properties.1

Though they were once considered a high-society luxury, Epsom salt is now super accessible to the masses—it’s sold in bags or boxes at most drugstores and supermarkets, usually for less than $10, and your mom probably has some under her bathroom sink. And while Epsom salt has been connected to all sorts of wellness benefits, it’s probably most known for its alleged pain-relieving properties. You may have seen a fitness influencer suggest an Epsom salt bath to relieve muscle aches after a tough training day or long run, or perhaps your pregnant friend has been trying an Epsom soak to soothe their sore feet.

But just because a wellness practice is trendy doesn’t make it legit. Below, experts explain what you should know about the potential benefits of Epsom salt baths (and Epsom salts in general)—and which claims you should take with, ahem, a grain of salt.

What is Epsom salt? | Benefits of Epsom salt baths | Epsom salt for sore muscles | Benefits for skin care | Potential risks | How to make an Epsom salt bath

What exactly is Epsom salt?

Epsom salt is a form of magnesium called magnesium sulfate, Chris D’Adamo, PhD, director of the Center for Integrative Medicine at the University of Maryland School of Medicine, tells SELF. Magnesium plays a role in more than 300 enzyme reactions in the body that affect muscle and nerve function, blood sugar and pressure regulation, bone growth, electrolyte function, energy production, and more. The primary source of magnesium for most people is food—leafy greens, fish, legumes, and whole grains are all high in the important mineral.

In terms of its medical applications, hospitals sometimes use Epsom salt to treat patients, Dr. D’Adamo says. Doctors may inject intravenous (IV) magnesium sulfate for pain and blood pressure regulation, for example, particularly among pregnant people with preeclampsia, he says.2 And health care practitioners also sometimes use IV and oral magnesium sulfate supplements to treat chronic pain conditions, including migraine, or to address magnesium deficiencies, he adds.3

Considering that magnesium in general is extremely important for keeping your body running in top form (and there’s research to suggest that a good proportion of people have lower-than-optimal levels of the mineral) and magnesium sulfate, specifically, is commonly used as a medical treatment, it’s not a stretch to think that an Epsom salt bath may do your body good. Which leads us to…

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Are there any proven benefits of Epsom salt baths?

First, it’s worth knowing that there are some benefits to taking any bath. It can help your sleep, for one thing, and not just because it’s soothing and de-stressing (which it can be). Warm water also increases your core body temperature, so when you get out of the tub (or shower), your body temperature begins to drop, which signals to your brain that it’s time for rest. (That’s also why sleep experts recommend snoozing in a cool room.) In fact, research suggests that a 10-minute soak in the tub (or warm shower) one to two hours before bedtime can help you fall asleep faster and feel as if you’ve had a better night’s rest.4

But what about the benefits of an Epsom salt bath, specifically? To reap any potential perks—beyond the soothing nature of the warm water—you’d need to be able to get the magnesium into your body in some way, where it can then create physiological changes. That could be either by absorbing the magnesium in the bathwater through your skin or inhaling it from the steam of the hot water, says Dr. D’Adamo.