Is bathing with Epsom salts highly toxic? No, that's not true: Toxicology experts told Lead Stories the claim that bathing with Epsom salts is toxic is "completely false" and "there is no toxicity associated with salt." Poison control agencies such as the Missouri Poison Center classify the salt as "generally safe" and "low risk" when used as the directions intended.
The claim appeared on Facebook (archived here) on November 18, 2023. It read:
Epsom Salts are highly toxic, poison. Synthetically derived in a laboratory and releases sulfuric acid in your bath tub. I started getting sever tremors from Epsom Salt baths and had no idea wtf at first, then did the research and learned that only the Magnesium Flakes (magnesium chloride) are mined and healthy, the salts are no bueno. THE MORE YOU KNOW....
This is what the post looked like on Facebook at the time of writing:
(Source: Facebook screenshot taken on Mon Nov 20 16:15:30 2023 UTC)
Lead Stories spoke to Kabrena Rodda, Ph.D. (archived here), group leader of analytical chemistry and instrumentation at Pacific Northwest National Laboratory. In emails on November 20 and 21, 2023, she responded to the claim:
The claim that bathing in Epsom salt is highly toxic is completely false. Epsom salt are magnesium sulfate (chemical formula MgSO4) which is a salt, meaning that when placed in water the magnesium and sulfate ions separate to produce a solution containing 1 Mg2+ and 2 SO4-ions.
In chemistry, a salt is defined as a substance that is produced by the reaction of an acid and a base. Epsom salt is made up of sulfur (the acid) and magnesium (the base) and oxygen.
Rodda mentioned in her response that the Facebook post said magnesium chloride would be a better alternative. She debunked this claim as well in her November 20, 2023, email:
The poster incorrectly states that magnesium chloride (chemical formula MgCl2) is better/healthier - but in reality it is just another salt. When magnesium chloride is placed in water it forms a solution containing 1 Mg2+ and 2 Cl- ions.
What are some common examples of magnesium and sulfate ions that show the ingredients of Epsom salt are not toxic? Rodda listed many things in her November 21, 2023, email: Magnesium ions occur naturally in the body and are used to carry out physiological roles, like "muscle contraction" and "flow of blood through the body." Common items that contain sulfate ions are "shampoo, body wash, face cleanser, and toothpaste."
Lead Stories also contacted Hans Plugge (archived here), a principal at Safer Chemical Analytics, LLC (archived here) who was a former senior toxicologist, about this claim. In a November 22, 2023, phone call he called the claim "garbage" and expounded:
Basically, there is no toxicity associated with salt ... if it's on your skin, there is no acid formation ... for any of these two chemicals [magnesium and sulfur, as they make up the majority of Epsom salt].
Poison control agencies such as the Missouri Poison Center classify Epsom salts as a "low risk" substance and cite only side effects (archived here) of "stomach upset, bloating" and "laxative effect, diarrhea" if Epsom salt is ingested. However, the post on Facebook referred to bathing with Epsom salts, which is how it's usually used. The Missouri Poison Center page classifies Epsom salt as "generally safe" when used as the directions intend.
Other Lead Stories articles on claims related to Epsom salt are here.
