Epsom salt is a popular remedy for many ailments.

People use it to ease health problems, such as muscle soreness and stress. It's also affordable, easy to use, and harmless when used appropriately.

This article provides a comprehensive overview of Epsom salt, including its benefits, uses, and side effects.

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Epsom salt is also known as magnesium sulfate. It's a chemical compound made up of magnesium, sulfur, and oxygen.

It gets its name from the town of Epsom in Surrey, England, where it was originally discovered.

Despite its name, Epsom salt is a completely different compound than table salt. It was most likely termed "salt" because of its chemical structure.

It has an appearance similar to table salt and is often dissolved in baths, which is why you may also know it as "bath salt." While it looks similar to table salt, its taste is distinctly different. Epsom salt is quite bitter and unpalatable.

Some people still consume it by dissolving the salt in water and drinking it. However, due to its taste, you probably don’t want to add it to food.

For hundreds of years, this salt has been used to treat ailments, such as constipation, insomnia, and fibromyalgia. Unfortunately, its effects on these conditions are not well researched.

Most of the reported benefits of Epsom salt are attributed to its magnesium, a mineral that a lot of people do not get enough of.

You can find Epsom salt online and at most drug and grocery stores. It’s typically located in the pharmacy or cosmetic area.

Summary Epsom salt — otherwise known as bath salt or magnesium sulfate — is a mineral compound believed to have many health benefits.

When Epsom salt is dissolved in water, it releases magnesium and sulfate ions.

The idea is that these particles can be absorbed through your skin, providing you with magnesium and sulfates — which serve important bodily functions.

Despite claims on the contrary, there is no good evidence that magnesium or sulfates are absorbed into your body through the skin (1).

Yet the most common use for Epsom salt is in baths, where it is simply dissolved in bathwater.

However, it can also be applied to your skin as a cosmetic or taken by mouth as a magnesium supplement or a laxative.

Summary Epsom salt dissolves in water and so can be added to baths and used as a cosmetic. However, there is no evidence that your body can absorb its minerals through the skin.

Many people, including some healthcare professionals, claim Epsom salt is therapeutic and use it as an alternative treatment for several conditions.

Provides Magnesium

Magnesium is the fourth most abundant mineral in the body, the first being calcium.

It is involved in more than 325 biochemical reactions that benefit your heart and nervous system.

Many people do not consume enough magnesium. Even if you do, factors such as dietary phytates and oxalates can interfere with how much your body absorbs (2).

While magnesium sulfate has value as a magnesium supplement, some people claim that magnesium may be better absorbed via Epsom salt baths than when taken by mouth.

This claim is not based on any available evidence.

Proponents of the theory point to an unpublished study in 19 healthy people. The researchers claimed that all but three of the participants showed higher blood magnesium levels after soaking in an Epsom salt bath.

However, no statistical tests were performed and the study lacked a control group (3).

As a result, its conclusions were unfounded and highly questionable.

Researchers agree that magnesium is not absorbed through people’s skin — at least not in any scientifically relevant amounts (1).

Promotes Sleep and Stress Reduction

Adequate magnesium levels are essential for sleep and stress management, likely because magnesium helps your brain produce neurotransmitters that induce sleep and reduce stress (4).

Magnesium may also help your body produce melatonin, a hormone that promotes sleep (5).

Low magnesium levels may negatively affect sleep quality and stress. Some people claim that taking Epsom salt baths can reverse these issues by allowing your body to absorb magnesium through the skin.

It’s more likely that the calming effects of Epsom salt baths are simply due to the relaxation caused by taking hot baths.

Helps With Constipation

Magnesium is often used to treat constipation.

It appears to be helpful because it draws water into your colon, which promotes bowel movements (6, 7).

Most often, magnesium is taken by mouth for constipation relief in the form of magnesium citrate or magnesium hydroxide.

However, taking Epsom salt is also said to be effective, although it is not well studied. Nevertheless, the FDA lists it as an approved laxative.

It can be taken by mouth with water according to the directions on the package.

Adults are usually advised to take 2–6 teaspoons (10–30 grams) of Epsom salt at a time, dissolved in at least 8 ounces (237 ml) of water and consumed immediately. You can expect a laxative effect in 30 minutes to 6 hours.

You should also know that consuming Epsom salt may produce unpleasant side effects, such as bloating and liquid stool (7).

It should only be used occasionally as a laxative, not for long-term relief.

Exercise Performance and Recovery

Some people claim that taking Epsom salt baths can reduce muscle soreness and relieve cramps — both important factors for exercise performance and recovery.

It is well known that adequate magnesium levels are helpful for exercise because magnesium helps your body use glucose and lactic acid (8).

While relaxing in a hot bath may help soothe aching muscles, there is no evidence that people absorb bathwater magnesium through their skin (1).

On the other hand, oral supplements can effectively stave off magnesium insufficiency or deficiency.

Athletes are prone to low magnesium levels, so health professionals often recommend that they take magnesium supplements to ensure optimal levels.

While magnesium is clearly important for exercise, the use of bath salt to enhance fitness is not well researched. At this point, the supposed benefits are purely anecdotal.

Reduced Pain and Swelling

Another common claim is that Epsom salt helps reduce pain and swelling.

Many people report that taking Epsom salt baths improves symptoms of fibromyalgia and arthritis.

Again, the magnesium is deemed responsible for these effects, since many people with fibromyalgia and arthritis are deficient in this mineral.

One study in 15 women with fibromyalgia concluded that applying magnesium chloride to the skin may be beneficial for reducing symptoms (9).

However, this study was based on questionnaires and lacked a control group. Its results should be taken with a grain of salt.

Summary Most of the purported benefits of Epsom bath salts are anecdotal. On the other hand, oral magnesium supplements may benefit sleep, stress, digestion, exercise, and pain in people who are deficient.

While Epsom salt is generally safe, there are a few negative effects that can occur if you use it incorrectly. This is only a concern when you take it by mouth.

First of all, the magnesium sulfate in it can have a laxative effect. Consuming it may result in diarrhea, bloating, or upset stomach.

If you use it as a laxative, make sure to drink plenty of water, which may reduce digestive discomfort. Furthermore, never take more than the recommended dosage without first consulting your doctor.

Some cases of magnesium overdose have been reported, in which people took too much Epsom salt. Symptoms include nausea, headache, lightheadedness, and flushed skin (2, 10).

In extreme cases, magnesium overdose can lead to heart problems, coma, paralysis, and death. This is unlikely as long as you take it in appropriate amounts as recommended by your doctor or listed on the package (2, 10).

Contact your doctor if you experience signs of an allergic reaction or other serious side effects.

Summary The magnesium sulfate in Epsom salt can produce side effects when taken by mouth. You can prevent these by using it correctly and talking with your doctor before increasing your dosage.

Here are a few of the most common ways to use Epsom salt.

Bath

The most common use is taking what's called an Epsom salt bath.

To do this, add 2 cups (about 475 grams) of Epsom salt to the water in a standard-sized bathtub and soak your body for at least 15 minutes.

You can also put the Epsom salt under running water if you want it to dissolve more quickly.

While hot baths can be relaxing, there is currently no good evidence for the benefits of an Epsom salt bath in itself.

Beauty

Epsom salt may be used as a beauty product for skin and hair. To use it as an exfoliant, just place some in your hand, dampen it and massage it into your skin.

Some people claim it's a useful addition to facial wash, since it may help cleanse pores.

Just a 1/2 teaspoon (2.5 grams) will do the trick. Simply combine it with your own cleansing cream and massage onto the skin.

It can also be added to conditioner and may help add volume to your hair. For this effect, combine equal parts conditioner and Epsom salt. Work the mixture through your hair and leave for 20 minutes, then rinse.

These uses are entirely anecdotal and unsupported by any studies. Remember that it works differently for everyone and that you may not experience the reported benefits.

Laxative

Epsom salt can be taken by mouth as a magnesium supplement or as a laxative.

Most brands recommend taking 2–6 teaspoons (10–30 grams) per day, dissolved in water, as a maximum for adults.

Approximately 1–2 teaspoons (5–10 grams) is generally enough for children.

Consult with your doctor if you need a more individualized dosage or if you want to increase the dose to more than what is listed on the package.

Unless you have the consent of a doctor, never ingest more than the upper limit of intake stated on the package. Taking more than you need could lead to magnesium sulfate poisoning.

If you want to begin taking Epsom salt by mouth, start slowly. Try consuming 1–2 teaspoons (5–10 grams) at a time and gradually increase the dose as needed.

Remember that everyone's magnesium needs are different. You may need more or less than the recommended dose, depending on how your body reacts and what exactly you are using it for.

Additionally, when consuming Epsom salt, make sure to use pure, supplement-grade Epsom salt that does not have any added scents or coloring.

Summary Epsom salt can be dissolved in baths and used as a beauty product. It can also be consumed with water as a magnesium supplement or laxative.

Epsom salt may be helpful in treating magnesium deficiency or constipation when taken as a supplement. It can also be used as a beauty product or bath salt.

There isn't a lot of evidence to support all of its reported benefits. Its positive effects are mostly anecdotal at this point, and more research is needed on its functions.

However, Epsom salt is generally safe and easy to use.

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