Posted by iHerb Customer on May 30, 2012 | Verified Purchase
great product. comes from a mine. quality testing ensures no lead, mercury or other heavy metals. beware of mag from Salt Lake, UT, because of mercury levels. from what i've read, mag chloride is one of the most bioavailable forms of mag. i use transdermal magnesium therapy, but don't always have time to let my skin absorb it, so its nice to have an oral option on busy days.