What Are Epsom Salts?

What research says about use for soreness, skin conditions, and more

Epsom salts

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Epsom salts have long been touted as a natural remedy for sore muscles, minor sprains, swollen feet, irritated or scaly skin, and minor bruises. The salts are used in a soaking solution or relaxing bath. Though no well-controlled research studies have confirmed that these salts (magnesium sulfate) are effective for topical uses, many people still use Epsom salts for these purposes and cite personal benefits.

It may actually come as a surprise that the only FDA-approved use for Epsom salts is as an oral osmotic laxative to relieve occasional constipation.

Here's what you can expect from using Epsom salts and how to use them safely.

What Are Epsom Salts?

Epsom salts are a naturally occurring chemical compound called magnesium sulfate. They are called "salts" because of their crystalline chemical structure. While Epsom salts look a bit like coarse salts used to season food, they are not used in cooking.

"Epsom" is not a brand name. These salts were named after Epsom, a saline spring in Surrey, England.

Uses

Epsom salts may be used in baths or soaks, or taken orally, depending on the intended use.

In Baths and Soaks

Epsom salts are dissolved in the water. People soak the achy area in the solution.

It is commonly said that the solution draws out substances or fluids. As such, Epsom salts are commonly used in foot soaks for tired or swollen feet or ankles.

According to anecdotal evidence, the use of Epsom salts can soothe sore muscles and help eliminate itchiness caused by poison ivy or mosquito bites. People with psoriasis also use them to help soften skin.

Many other benefits are ascribed to Epsom salts by those who believe that magnesium can be absorbed through the skin, including effects on mood and relieving stress, as well as other benefits seen in people who have magnesium deficiency due to a poor diet.

Taken Orally

Pure Epsom salts (those that do not contain fragrance or other additives) can be used orally as a laxative as follows:

  • Adults and children age 12 years and older: 2 teaspoons to 4 teaspoons dissolved in 8 ounces of water, not to exceed two doses per day
  • Children age 6 years to 11 years: 1 teaspoon to 2 teaspoons dissolved in 8 ounces of water, not to exceed two doses per day

It should result in a bowel movement within a half hour to six hours.

Efficacy

No well-controlled studies have shown Epsom salts soaks to be beneficial for soothing sore muscles or swollen feet, but it has a long history of use and many advocates. Taking a nice warm bath or foot soak may certainly be stress-relieving and relaxing in and of itself.

There are no well-controlled studies that show magnesium can be absorbed through the skin, such as in a bath, soak, or cream application. A research review showed that the studies that found some evidence topical absorption were poorly designed, and other researchers could not reproduce these results. However, popular articles on Epsom salts often quote the conclusions of these low-quality studies.

Rather than using a soak to correct a magnesium deficiency, improving your dietary sources or taking an oral magnesium supplement that provides an appropriate dose of magnesium is preferred. Talk to your doctor if you think you have a magnesium deficiency to get a recommendation.

When taken internally, magnesium sulfate in Epsom salts is not as well-absorbed as several other compounds of magnesium, such as magnesium chloride.

Side Effects

Epsom salts should be used with some caution.

Epsom salts can dry your skin out, and this can be a particular problem for those who deal with dry skin regularly and during the winter months.

Start with just a little salt (1/4 cup) in the bath and gradually increase as tolerated. Monitor your skin closely for dryness, and be sure to moisturize the skin after a soak.

You should not use Epsom salts for soaking skin that has an open wound, skin infection, or severe burn without first consulting your doctor. This can worsen some common skin infections.

Taking Epsom salts orally can produce diarrhea, discomfort, and dehydration.

Talk to your doctor before using Epsom salts orally as a laxative if you have kidney disease, stomach pain, nausea, or vomiting, or if you had a sudden change in your bowel habits that has lasted more than two weeks. Epsom salts should also not be used by those who are on a magnesium-restricted diet.

If you are taking it for constipation, talk to your doctor if you don't have a bowel movement or you need to take it to produce a bowel movement for more than a week.

How to Make an Epsom Salts Bath

Integrative medicine practitioners may suggest an Epsom salts bath for various purposes. One such doctor, Naoki Umeda, M.D. from Cleveland Clinic’s Center for Integrative Medicine, recommends dissolving 1 cup (300 grams) of Epsom salts in a tub of bathwater. Enjoy a soak for 10 minutes to 15 minutes.

The package of Epsom salts that you purchase may have differing instructions. Some make no suggestion, while others provide different amounts for different uses.

For example, directions may state that you should use 2 cups of Epsom salts in a tub of bathwater as a body soak, or 1 cup in a gallon of warm water for a foot soak.

As a soaking aid for minor sprains and bruises, some package labels note dissolving 2 cups of Epsom salts per gallon of warm water and applying it to the area with a bandage or towel for 30 minutes, up to three times per day.

Follow the instructions provided by your practitioner or outlined on the package.

How Often Can Epsom Salts Be Used?

Occasional use of Epsom salts (especially for soaking the feet) does not seem to be harmful. If using Epsom salts in a bath, try doing so no more than once a week at first to see how your skin reacts.

It may be that you need to avoid Epsom salt baths in the wintertime when both the air and your skin tend to be drier. You may be able to take them more frequently in the summer when the humidity is higher.

A Word From Verywell

While there have been no controlled studies, a number of people say Epsom salts are helpful for a variety of minor issues. You may want to check with your doctor before using them if you have any underlying health conditions.

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