What is Epsom salt lotion and is it better than a bath?

Epsom salt lotion is usually a skin moisturizer with branding around Epsom salt or magnesium. The lotion may feel soothing because it hydrates skin, not because magnesium is dramatically changing your body through the bottle.

That does not mean it is useless. If it helps your skin feel softer or less dry, that is a real cosmetic benefit. But the stronger health claims are where the evidence usually gets thin.

So the honest read is simple: think of it as a lotion first and a medical product second. Most of the benefit comes from the moisturizing base.