Magnesium oil

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Magnesium oil is not really oil. It’s a concentrated solution of magnesium chloride in water (also called transdermal magnesium or magnesium hexahydrate). It feels oily to the touch, but it mixes with water because it’s an aqueous solution. People apply it to the skin as an alternative to taking magnesium by mouth, but there is little evidence that magnesium is absorbed through the skin in meaningful amounts, so its effectiveness is not supported by science.