1 Pound Magnesium Chloride Hexahydrate (454 g) – Pharmaceutical Grade crystal powder. This product is EUR, BP, and USP compliant, third-party tested for heavy metals, and manufactured in facilities certified to GMP, ISO 22000, and ISO 22716 standards. The powder dissolves easily in purified water and supports cellular magnesium levels. Heavy metal analysis is available upon request. Scroll down to view third-party certificates and additional quality data.