Oral magnesium supplementation with 360 mg elemental magnesium daily for 16 weeks significantly increases plasma magnesium levels by approximately 0.056 mmol/L in older adults with pre-diabetes and hypomagnesemia, and does not significantly alter insulin, HOMA-IR, HbA1c, or inflammatory markers.

Taking magnesium supplements raises magnesium levels in the blood, which allows more magnesium to enter muscle and fat cells. Inside these cells, magnesium helps activate the insulin receptor, which then signals the cell to pull glucose from the blood. This lowers blood sugar, but only if the cells were initially low in magnesium. In people with pre-diabetes and low magnesium, this process works, but it does not change insulin resistance, inflammation, or long-term blood sugar markers because the underlying damage to insulin signaling is too advanced.