Magnesium Chloride in the form of magnesium spray is ideal for use in transdermal applications because it is rapidly absorbed through the skin, and therefore rapidly can elevate low or depleted levels of magnesium in the body. Use before going to sleep. If you suffer from muscle tension, we recommend using this spray on various parts of your body (shoulders, back, feet etc) to relieve muscle pain. Very effective in reducing muscle tension and muscle cramps.