How do Epsom Salts work?

…For sore muscles & so on?

Couldn’t decide where to make my first post - here or The Pit. I guess I’ll take the high road.

Epsom Salt (magnesium sulfate) solution is widely used as as a soak for aching joints, strains, sprains, etc. It’s also used orally for constipation - in that case, the primary mechanism of action is the formation of an osmotic gradient. In other words, more electrolytes are in the intestine than outside, so water tends to be drawn into the intestine so that equilibrium may be approached.

That being said, I could find precious little info on the topical use of Epsom Salts in any of my references - quite a surprise to me (I wanted to have something concrete to back me up - I know how the Dopers are). I would speculate, however, that the mechanism is the same. For example, you place a sprained ankle in a bucket of Epsom Salt solution and the tendency would be for excess fluid in the damaged joint to pass across the skin into the more concentrated solution outside. Swelling is reduced, therefore pain is lessened. I’m not sure as to the degree of swelling reduction, however. I haven’t had much luck with Epsom Salt soaks - usually some ibuprofen and rest does it for me.

Thanks & welcome, Gingko!

That’s interesting. I just couldn’t figure out how something that just touches the skin could affect muscles & joints on the inside, any more than the hot bath water would.

We discussed this several months back over at Fathom, FFF thread - Epsom Salt

I’ll quote myself quoting this site

"Magnesium. If I had to recommend one nutrient to asthmatics, it would be magnesium. Over half a century ago, scientists reported that magnesium sulfate worked as a natural bronchodilator, one that opened constricted bronchial tubes without side effects. Though magnesium alone cannot cure a severe attack, intravenous magnesium sulfate is now used at many hospitals along with drugs to treat attacks. Magnesium helps relax smooth muscle, rapidly opens the bronchial tubes, and as at least one report has shown, can prevent intubation (a painful procedure in which a tube is forced down the throat to help a patient breathe).

Magnesium works at a cellular level, most likely by displacing calcium. Calcium stimulates one of the primary allergic cells in the body-the mast cell-to burst and release a flood of histamine. It is also necessary for muscle contraction. Magnesium, in contrast, helps stabilize the mast cell and relax muscles, so it functions as both an antiinflammatory nutrient and as a bronchodilator."