Detailed guides to painful problems, treatments & more

Osmosis sucks water, not toxins 

 •  • by Paul Ingraham
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Weekly nuggets of pain science news and insight, usually 100-300 words, with the occasional longer post. The blog is the “director’s commentary” on the core content of a library of major articles and books about common painful problems and popular treatments. See the blog archives or updates for the whole site.

Many people get osmosis backwards: it’s the solvent (eg water) that moves … not the solutes! In other words, osmosis can only suck things dry, but it cannot suck “stuff” (eg toxins) out of anything. This ancient point of confusion has now been made even clearer in a minor update to the Epsom salts article, along with some details about what can get through skin and what can’t and why (e.g. 500 Dalton rule, which is neat). Maybe this will put a stop to the weird osmosis-confusion e-mail I’ve been getting for a decade? Yeah, probably not.