Can taking magnesium before bed improve insulin sensitivity?

Your body needs magnesium for many important functions: the mineral supports muscle and nerve function, helps regulate blood sugar and blood pressure, and is necessary for energy production. If you don’t get enough magnesium, you may experience a variety of health problems, including fatigue, weakness, nausea, vomiting, and loss of appetite.

Taking a magnesium supplement before bed each night might also improve insulin sensitivity. To learn more about the relationship between magnesium supplementation and insulin sensitivity, we spoke with Suma Gondi, MD, an endocrinologist at Mount Sinai.

Q: How does magnesium relate to insulin sensitivity?

Gondi: Magnesium plays an important role in several cellular processes involved in glucose metabolism and insulin function. It helps activate enzymes that activate insulin receptors, promote glucose uptake into cells, and secrete insulin from the pancreas. Due to these functions, inadequate levels of magnesium can negatively affect insulin sensitivity.

Evidence that magnesium supplementation improves insulin sensitivity is mixed. Some studies have shown that magnesium can improve markers of insulin resistance. However, others have shown no significant improvement in insulin sensitivity in people with type 2 diabetes and low magnesium levels.

Research also suggests that people with higher dietary magnesium intake have a lower risk of type 2 diabetes than those with low intake. However, there is insufficient evidence to conclude that magnesium supplementation itself reduces the risk of developing type 2 diabetes. The American Diabetes Association does not recommend routine magnesium supplementation for people with diabetes unless they have a confirmed magnesium deficiency.

Q: If someone wants to try this, is timing important? Should you really take magnesium right before bed?

Gondi: There is currently no clinical evidence that taking magnesium at bedtime is more effective than taking it at other times of the day in improving insulin sensitivity. Any potential benefits appear to result from maintaining adequate magnesium levels over weeks or months rather than a specific timing of supplementation. Some studies have examined whether magnesium improves sleep quality, but the results have been inconsistent and remain inconclusive.

Q: How can people get more magnesium?

Gondi: The recommended dietary intake of magnesium for adults ages 31 to 50 is 320 milligrams for women and 420 milligrams for men, and 10 mg less for younger adults. Magnesium occurs naturally in many foods, especially fiber-rich foods like nuts, seeds, green leafy vegetables, and whole grains.

If you are trying to increase your magnesium intake, you should include the following in your diet:

• Green leafy vegetables
• Seeds
• Nut
• Whole grains
• Magnesium-enriched breakfast cereals

If possible, it’s best to get most of your magnesium from your diet (rather than from supplementation), but your doctor may recommend a supplement if you’re deficient.

Over-the-counter magnesium supplements are available in a variety of forms and doses, each with different absorption profiles and potential side effects. The appropriate dose should be determined in consultation with a healthcare professional.

Q: What safety precautions should people consider before trying this?

Gondi: Consulting a healthcare professional is especially important for people with kidney disease or those taking medications that may affect magnesium absorption, such as certain acid-reducing medications used to treat heartburn or osteoporosis.

A healthcare professional can measure magnesium levels using a blood test and determine if supplementation is appropriate. The most common side effect of magnesium supplements is diarrhea, which is more likely to occur at higher doses. Very high doses of magnesium can cause vomiting, low blood pressure and even cardiac arrhythmias.