Magnesium citrate. Polarised light micrograph of crystals of the oral drug Magnesium citrate. Known also as Trimagnesium-dicitrate. It is one of the organic magnesium salts, given to patients who are suffering deficiencies in magnesium. Magnesium citrate is usually given by mouth, often dissolved in water as a powder. The citrate acid-component is not harmful and is easily metabolised by the body. Magnesium is essential for bone and teeth formation, muscle contraction, and transmission of nerve impulses. Magnesium deficiency may be due to kidney disease or alcohol dependence. Magnesium is found in cereals, nuts, milk, fish and meat. Magnification: x24 at 6x7cm size. Magnification: x40 at 4x5 inch size.