Magnesium is an essential mineral involved in hundreds of processes in the body, and supplements are often promoted for benefits ranging from muscle function to sleep and relaxation. But more is not always better. For some people, particularly those with certain medical conditions or those taking specific medicines, magnesium supplements can cause problems or interfere with treatment.
The National Institutes of Health (NIH) notes that healthy kidneys normally remove excess magnesium through urine. However, high doses from supplements or medicines can cause diarrhoea, nausea and abdominal cramping, while extremely high levels can lead to low blood pressure, irregular heartbeat and, in severe cases, cardiac arrest.
