Our in-house magnesium spray is made with food grade magnesium chloride. (MgCl2). Magnesium oil is good for sleep, low magnesium, growing and general pains. Transdermal absorption is one of the best ways to use magnesium as it by-passes the gastrointestinal tract absorbing very quickly. Some will experience a slight tingle if magnesium levels are low however this subsides.