Epsom salt is, honestly, quite amazing.
A 20-30 minute soak in a fairly warm bath of Epsom salt gives me substantial pain relief for a substantial length of time. This is a big deal for someone with lupus, but people without lupus might derive some benefit as well.
My tub is big, so I use two cups of Epsom salt, measured carelessly, because the Epsom salt is usually chunky (having been stored in a humid bathroom) and does not fit neatly into a measuring cup.
I've found that I achieve my best water temperature if I get into the tub just as I begin to run the tap, and adjust the hot-cold ratio to my liking as it fills.
You don't want too hot a bath, or you will get woozy. At least, I do. I've almost fainted from too hot a bath.
But a nice, warm bath (just this side of hot, if you know what I mean), with Epsom salt and a few drops of lavender essential oil, is legitimately therapeutic.
I've found that the pain relieving effects from an Epsom salt bath are more comprehensive and longer lasting than a what I get from a professional, therapeutic massage. . . and for significantly less expense.
I am thankful for Epsom salt.