Magnesium and kidney stones: a concise narrative review

Magnesium is a potentially relevant factor in kidney stone disease (KSD), particularly in calcium-containing stones. This narrative review summarizes magnesium metabolism, its anti-lithogenic mechanisms, and the current evidence on supplementation in KSD. Magnesium may reduce stone risk through intestinal oxalate binding, inhibition of calcium oxalate crystallization, and increased urinary citrate excretion. A systematic search of PubMed, Web of Science, and Embase (up to April 2026) identified interventional and observational studies evaluating magnesium and urinary or clinical outcomes. Study quality was assessed using the GRADE framework, and the review followed SANRA guidance. Fifteen studies were included, comprising metabolic studies, observational analyses, and four randomized controlled trials. Observational studies consistently report an inverse association between urinary magnesium and stone risk. Interventional studies show improvements in urinary parameters, including increased magnesium and citrate excretion and reduced oxalate, particularly when taken with meals. However, randomized evidence remains limited and heterogeneous. Current evidence does not support routine magnesium supplementation over established therapies such as potassium citrate. Nevertheless, magnesium, especially citrate-containing formulations, may be considered in selected patients, including those with hypomagnesuria, hypocitraturia, or intolerance to potassium salts. Larger, high-quality randomized trials are needed.