Does magnesium help with insulin resistance?

Magnesium plays a direct role in how the body processes insulin. The mineral is needed for an enzyme (tyrosine kinase) that activates the insulin receptor on cells. Without enough magnesium inside the cell, that receptor functions less effectively, cells absorb less glucose, and the body loses additional magnesium through the kidneys because insulin no longer properly regulates its uptake. This creates a self-reinforcing problem.

Low magnesium levels in the blood have repeatedly been found in people with insulin resistance and type 2 diabetes. It is not certain which direction the causality runs: low magnesium can reduce insulin sensitivity, but conversely, insulin resistance itself can also lead to additional magnesium loss. Both pathways may operate simultaneously.

Randomised trials show that magnesium supplements can genuinely help. A meta-analysis of double-blind trials found a significant reduction in fasting blood sugar in people with diabetes. In people at elevated risk of diabetes, insulin sensitivity also improved and they performed better on a glucose tolerance test. A small separate trial in forty women with polycystic ovary syndrome found a significant reduction in insulin and insulin resistance after two months of 250 mg magnesium oxide per day. Because that trial was small and conducted in a specific group only, it is wise not to simply generalise the findings to everyone.

Getting magnesium through diet also appears to be beneficial for broader metabolic markers such as blood pressure and triglycerides. In a large observational study of more than 21,000 people, higher magnesium intake was linked to a lower risk of serious heart and kidney disease and to reduced mortality, although that alone does not prove a causal relationship.