Many people have heard that adding Epsom salt to bath water eases sore muscles and promotes healing after workouts, muscle strain or other injury. Unfortunately, there's no hard research to back up those claims, according to Paul Ingraham, the associate editor of the Science-Based Medicine website. If you go strictly by the available scientific evidence, the only benefit of an Epsom salt bath is that some people enjoy the way it makes their bath water feel. Some people describe the water as smooth or silky.
Numerous websites extol the supposed benefits of Epsom salts, including -- not surprisingly -- the Epsom Salt Council, which claims that an Epsom salt bath is a "popular remedy" to ease muscle pains and even fade bruises. The council also claims that "Many athletes use Epsom salt as a natural remedy to help their bodies recover faster." When you read claims like this, be aware that even if something is a "popular remedy" that "many athletes use," that's not the same as saying that it's been proved to do anything, scientifically speaking. Bloodletting and exorcism were once "popular remedies" too.
No Harm if You Want to Use It
Unlike bloodletting and exorcism, however, soaking in an Epsom salt bath won't hurt you. The Epsom Salt Council recommends adding 2 cups of Epsom salt to a typical-size bathtub. Whether or not the Epsom salt eases muscle pain, many people find the moist heat of soaking in a bath soothing to tight muscles. In fact, the Columbia University Medical Center website recommends moist heat as a home treatment for tight or spasming muscles. Unfortunately, when it comes to a faster recovery time for athletes' muscles, Ingraham notes that nothing has been found to do that.
Effects on Blood Chemistry?
Epsom salt is another name for the chemical magnesium sulfate. Rosemary Waring, a researcher at the University of Birmingham in the United Kingdom, did a small study with just 19 people to study whether soaking in Epsom salt baths increased the levels of magnesium or sulfate in the blood. She noted some very small increases, suggesting that soaking in a bath might affect your blood chemistry by a minute amount. However, this research has not been published or subjected to peer review, nor has it been replicated. If the effects are true, they are very small.
Dangers of Epsom Salt
Although soaking in an Epsom salt bath is harmless enough, if someone ingests a lot of this chemical -- say, a child who finds it and eats it -- it's potentially dangerous, even life threatening. People who've taken large amounts of Epsom salts internally, whether by accidental poisoning, by using it as an enema, or even just by using Epsom salt as a gargle, have occasionally died. Keep Epsom salt out of the reach of anyone who might use it inappropriately, and get emergency medical attention if poisoning is suspected.