Magnesium deficiency, which is prevalent in the US population, results in increased levels of cytosolic free calcium.98 Intracellular free calcium levels above the normal range are cytotoxic causing calcification of mitochondria and cell death. The cell membrane possesses an ATP-dependant calcium pump that keeps intracellular levels of free ionized calcium within narrow limits. This calcium pump is magnesium-dependent for normal function. Magnesium deficiency results in a defective calcium pump and intracellular accumulation of ionized calcium. Inadequate iodine/ Iodide intake below orthoiodosupplementation results in decreased levels of delta-iodo-lactone. Combined magnesium and iodine/iodide deficiency based on the concept of orthoiodosupplementation are the basic factors involved in the oxidative damage caused by excess H2O2 (Hydrogen-Peroxid) and reactive oxygen species. If this proposed mechanism is valid, orthoiodosupplementation,30 combined with magnesium intake between 800-1,200 mg/day, a daily amount this author recommended 21 years ago 98 for magnesium sufficiency, should reverse autoimmune thyroiditis. This nutritional approach is also effective in Graves' autoimmune thyroiditis as previously discussed.