Epsom salt information and brand comparison
Can magnesium be absorbed into the body from an epsom salt bath?
I remember being surprised when I first heard epsom salt baths suggested as a good way to raise magnesium levels in the body. My favorite expert on myofascial pain, Paul Ingraham, has the same skepticism and outlines the lack of evidence for absorption.
The sole evidence I'm aware of that epsom salt baths raise magnesium (and sulfate) levels in the body comes from an experiment where 19 volunteers took 12-minute epsom salt baths. Most of them had a significant rise in blood levels of magnesium, and all of them showed a significant rise in sulfate levels. I'd be happier if there was more evidence, but this experiment is enough to convince me that epsom salt baths are probably beneficial.
How much should be used in a bath for raising magnesium/sulfate levels?
Judging by the experiment above, 1-1.5 pounds in a 15 gallon bathtub should be a good amount. Smaller amounts are probably still beneficial if you find larger amounts make the water unpleasant.
Heavy metal content
I'm not aware of evidence that the tiny amount of heavy metals that may be present in epsom salts are any kind of risk when used in baths. When taken internally (sometimes done for irregular heartbeats or as a laxative), it'd be ideal to choose a brand that makes their heavy metal testing public. Unfortunately, all of the brands I've found that have heavy metal analyses don't rate their products for internal use. If you know of a brand that does, please let me know in the comments.
Cheap bulk sources
These are the cheapest bulk sources I've found. You may be able to find even cheaper sources locally.
- For external use only
- Made in the US
- Has a Certificate of Analysis with arsenic, heavy metals (as lead), iron, and selenium levels.
$0.50/lb (without including shipping, see here for shipping details) directly from Liberty Naturals.
- For external use only
- Made in China, assembled in the US
- Data sheet / chemical analysis available showing iron and heavy metals (as lead) levels. It also includes Kosher certification, a GMO-free declaration, and microbial testing for Salmonella, Listeria, E. coli, and Staph aureus.
- You can choose a grain size (extra fine, fine, medium, or coarse)
$0.86/lb (when purchasing the giant 50lb package) with free shipping directly from SaltWorks. You can get it down to $0.58/lb if you've got room for 2000 pounds of it :)
Other brands
- Rated for internal use
- Made and assembled in the US
$0.72/lb from Walmart either online or in stores.
- Rated for internal use
- Unknown country of origin
$1.00/lb from CVS either online or in stores.
- Rated for internal use (only for the plain version)
- Made in the US
$0.83/lb from Walmart either online or in stores.
- Rated for internal use
- Unknown country of origin
Not available online, but you can check product availability using the Kroger web site.
- Rated for internal use
- Unknown country of origin
$2.76/lb from Amazon. It's probably closer to $1/lb if you can find it locally.
- For external use only
- Made in the US
$3.21/lb directly from Mountain Rose Herbs.
- For external use only
- Made in the US
- Data sheet / chemical analysis available showing arsenic, iron, general heavy metals, and selenium content. It also declares it GMO-free, which isn't surprising for epsom salt.
$1.52/lb (when purchasing the largest package) directly from San Francisco Salt Company.
- For external use only
- Made in the US
- Data sheet / chemical analysis available showing arsenic, iron, general heavy metals, and selenium content. It also includes Kosher certification and a GMO-free declaration.
$1.75/lb (when purchasing the largest package) directly from San Francisco Salt Company.
- Rated for internal use
- Made in the US
Somewhat expensive online, the lowest price I've found is $2.30/lb (with shipping) from Amazon. It's probably much cheaper if you have a local Sam's Club membership (you can check availability of the product online).
- Rated for internal use
- Unknown country of origin
Not really worth buying online, the lowest price I've found is $3.21/lb from Amazon. It's probably around $1-$2/lb when purchasing locally.
- Rated for internal use
- Unknown country of origin
Not available online, but you can check local availability on Walgreens.com.
- Rated for internal use
- Unknown country of origin
Not really worth buying online, the lowest price I've found is $3.00/lb from Amazon. It's probably much cheaper locally.