Epsom Salt Sulfur Content


Does anyone know the Sulfur content of Epsom Salts?
I’m guessing it has 9.75mg, based on it’s Magnesium content of 7.5mg, but I can’t find a definite answer


According to this, it’s got 13% sulfur content by weight. No clue as to how much of that is bioavailable.


Short answer: If you’re talking about a 75mg “serving” of pure epsom salt, then you are about right.

jrowe’s link is correct. “Epsom salt” is the colloquial name for the hydrated chemical Magnesium Sulfate, or MgSO4-7H2O.

MgSO4-7H2O has a molecular mass of 246.47. Sulfur has a molar mass of 32.065. That means it is 13% sulfur (32.065 / 246.47).

So 1g of epsom salt has 130mg of sulfur and 99mg of Mg (the rest is oxygen and water).

Mg molar mass: 24.3050 -> 9.9%


Thanks a lot!
Now to edit my ingredient.
Epsom salts are so cheap, I’m surprised I haven’t seen anyone else using them for sulfur.


I’m definitely going to rework my recipe to incorporate epsom salts.


There is no dietary requirement for elemental sulfur. The nutritional requirement for “sulfur” refers to the sulfur-containing amino acids (SAAs) – specifically methionine and cysteine.

If your recipe has an adequate source of complete proteins, it is highly unlikely to be lacking in SAAs. There is no reason for people to be adding epsom salt or other sulfur-containing compounds to their recipes unless they serve some other purpose.

The “Sulfur” field in the nutritional profiles of the DIY site appears to be misleading a lot of people. It should really be re-labeled as “SAA” (or perhaps simply eliminated) to reduce this confusion.

For more details, please see the related posts in another thread:


FYI, epsom salt tastes like crap. (Just got some for bathing)


You’re better off getting your sulfur compounds from Epsom Salts transdermally. This will also give you magnesium in a form that has never been found to cause stomach upset.

Don’t EAT it, SOAK in it. This will be somewhat self-regulating, as well.

In other words, something like a quarter cup of epsom salts dissolved into either a warm bath, or in a foot-soaking pan, and then soaking for 15-20 minutes, will provide you all the magnesium and sulfur-compound your body wants, if you have a shortage. It will also help your joints feel better if you have any issues with them.