What’s In An Epsom Salt Bath?

Here at the Natural Athlete’s Clinic, we obviously have an inclination toward natural health and healing. We like to educate you about which natural therapies work, which ones don’t and why. That being said, we also like to employ some critical thinking to natural medicine therapies because, well frankly there’s a lot of uniformed stuff out there – most of which isn’t harmful, but rather it’s more disingenuous and lies somewhere between harmless and useless.

And on that note, while something may have no ‘proof’ or ‘evidence’, that doesn’t necessarily mean a therapy isn't helpful in certain situations. Take for example the ubiquitous Epsom salt bath, used by many a sore, tired athlete, including yours truly.

What is Epsom salt?

It’s really “Epsom salt”, not “Epsom salts”. There’s only one ingredient in the bag you can buy at any grocery or pharmacy and that is magnesium sulfate. A molecule of magnesium, a molecule of sulfur, and 4 molecules of oxygen. Nothing else. It’s called Epsom salt because it was originally derived from the mineral water in Epsom, England back in the day. Typical directions for an Epsom salt bath are to use anywhere from ½ cup to 2+ cups in a bath.

One teaspoon of Epsom salt contains about 5 grams (5000 mg) of magnesium sulfate. So a few cups is going to be hundreds of thousands of milligrams of magnesium. (Careful don’t drink any of your bath water- not that you would - because the other use for Epsom salt (magnesium) is as a laxative. It only takes about 300-400 milligrams orally for most people to experience this.)

Is magnesium good for you?

Yes! Magnesium is used in hundreds of enzyme reactions in your body. You use a lot of this mineral, and there’s reason to believe many people may not get adequate amounts – especially those who don’t eat enough real food (legumes, dark green leafies, fish, nut and seeds, whole grains and avocados for instance). There’s a lot of magnesium in dark chocolate and coffee too.

One of magnesium’s most important actions is that of a muscle relaxer. It works especially well inside the body in the smooth muscles that line our arteries, lungs and uterus and can be used for high blood pressure, asthma and premenstrual cramping, respectively (just to name a few uses.)

Magnesium is of course well absorbed taken by mouth, however as I mentioned earlier you don’t need a whole lot to overdose which the first sign tends to be diarrhea. Beyond that, you’ll get heart rhythm abnormalities and that’s a bad thing. (So don’t overdose on magnesium, ok?)

However, when it comes to absorbing Epsom salt (magnesium) through the skin, that’s a different story.

Huh? It’s not absorbed through my skin??

Yep that’s right. All across Internet land we have various experts and leading TV doctors saying how wonderfully magnesium is absorbed in a bath. Well, it just isn’t true. Your skin is basically waterproof, and doesn’t let much of anything in. True, if a drug or something else is combined with a fat-soluble carrier, you can drive many chemicals through the skin. But, sitting in a warm Epsom salt bath will do little to drive magnesium into your body.

So then why do I feel so good after an Epsom salt bath?

Minerals do cool things to water. Epsom salt will make the water feel slippery and silkier. Heavily salted water can actually become so dense that you can float in it – think of floating in the ocean versus your local pool.  Will the water make you feel a little more buoyant in an Epsom salt bath? Yes, and that may be part of why it feels so pleasant.  I think the real reason we feel so much better after a bath is because it’s warm, it’s soothing, it’s a chance to relax, etc.  But it’s highly doubtful you feel better because you’re absorbing a lot of magnesium and detoxing, which brings me to my next point.

They’re not a detox!

Ugg. I see and hear this everywhere. “Detox” is thrown about as a noun and verb so much these days it’s basically meaningless. What exactly are we detoxing with an Epsom salt bath? Not much, I can tell you that. Magnesium nor any other bath ingredient (including those ‘ionic foot baths’) can magically pull toxins or anything else out of your skin.

Sure, sweating is part of a detox, and that is good, but this has nothing to do with the magnesium in Epsom salt baths.  Show me a study where bath water contents are analyzed before and after an Epsom salt bath for anything toxic (other than the grime that comes off your naked body) and I’ll be the first to recommend it as a detox.  Until then, because there’s no evidence (and really no physiological way) magnesium can detox you from the outside in, let’s stop saying that Epsom salt baths are detoxifying!

I don’t mean to come across like a Debbie Downer when it comes to Epsom salt baths. They’re inexpensive, without side effects and will undoubtedly make you feel better after a running or cycling beatdown of any variety.  They’re great for gettin’ over it, period.

BUT…Epsom salt baths probably don’t work like everyone likes to say. Does that mean you should forget about them? Of course not! But I think you’d be better served (from a standpoint of magnesium’s benefits) by consuming a magnesium-rich diet (legumes, nuts, seeds, avocados, dark green leafys, fish, coffee, chocolate, etc) and using a magnesium supplement.

The best way to detox is to not put crappy food and chemicals into your body, make sure you exercise and sweat regularly, and take care of your liver and GI tract to ensure the nasty stuff you ingest and produce in your body gets removed efficiently.

So go ahead and take all the Epsom salt baths you want; just don’t expect to absorb a bunch of magnesium or have your body detox. :)