All Epsom salt contains the naturally occurring minerals of magnesium and sulfate. There are different ways of manufacturing and packaging Epsom salt, but chemically, it’s all exactly the same. There are also different “grades” of Epsom salt for different applications such as human use and agricultural applications. Any package that has a “drug facts” box or that’s labeled “USP” has been manufactured, tested and certified to meet stringent regulatory standards of the FDA and the United States Pharmacopeia, and is deemed safe and acceptable for human use. For human use, the Epsom Salt Council recommends only Epsom salt with the USP designation.
One of the earliest discoveries of magnesium sulfate, the scientific name of Epsom salt, occurred back in Shakespeare’s day in Epsom, England, which explains the first half of the name. The term “salt” probably refers to the specific chemical structure of the compound, although many people mistakenly assume it refers to the crystalline structure of Epsom salt, which has an appearance similar to that of table salt. (Table salt, of course, consists of sodium chloride, so it’s an entirely different substance than magnesium sulfate.)
No. In fact, Epsom salt is widely reported to soften skin, and it rinses away completely. While we don’t yet understand precisely why Epsom salt has a softening effect, the results have been widely reported for hundreds of years.
Most drug stores sell it in convenient, consumer-sized packages. Look for it where you find aspirin, Tylenol or Ace bandages (because it’s used as a treatment for muscle aches) or in the laxative section (magnesium sulfate is an effective, naturally occurring laxative).