Magnesium

Research summary

• Multiple independent meta-analyses of randomized trials, spanning from 2002 to 2025, consistently find magnesium supplementation produces a small but real reduction in blood pressure, with effects present across general and diabetic populations.
• On the dietary side, several dose-response meta-analyses of prospective cohorts link higher magnesium intake to lower risk of type 2 diabetes, with a dedicated dose-response analysis also linking intake to lower cardiovascular disease and all-cause mortality risk.
• For two commonly marketed uses — muscle cramps and sleep — the evidence is weaker: a Cochrane review found insufficient evidence that magnesium meaningfully reduces skeletal muscle cramps, and a meta-analysis specifically in older adults found only modest support for improving insomnia.
• Overall, magnesium's blood-pressure and diabetes-risk associations are its best-supported effects, while cramps and sleep claims rest on thinner evidence.