Maintaining healthy magnesium levels may reduce the risk of type 2 diabetes (T2D). However, more research is necessary to understand the impact of magnesium on those already living with T2D.

T2D develops when the body’s cells become resistant to insulin, a hormone that moves glucose from the blood to the cells for use as energy.

In T2D, blood glucose levels remain high unless a person takes steps to manage them. Blood glucose management can involve dietary changes, exercise, or medications. Consistently high blood glucose levels can increase a person’s risk of heart disease, stroke, nerve damage, and kidney disease.

Maintaining a balanced intake of essential nutrients is crucial for promoting health. Magnesium is a vital mineral with close links to blood glucose regulation. For this reason, researchers have looked into its relationship with T2D.

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Consuming enough magnesium supports many chemical reactions throughout the body, including blood glucose regulation.

According to the National Institutes of Health’s Office of Dietary Supplements (ODS), people with T2D and insulin resistance might have lower magnesium levels in their blood and eliminate more magnesium through their urine. As a result, they have a higher risk of magnesium deficiency.

According to a 2023 research review, people with T2D are more likely to have low magnesium levels than those with type 1 diabetes (T1D). This difference may occur because the development of T2D is associated with insulin resistance, while T1D relates to the immune system destroying cells in the pancreas that make insulin.

The ODS also suggests that diets higher in magnesium have a link to a lower risk of T2D. In a 2020 review of 41 studies, researchers found that the population with the highest magnesium intake had a 22% lower risk of T2D than the population with the lowest intake.

However, studies examining the effects of magnesium supplementation on people already living with T2D are small and have mixed results.

For example, in a small 2024 study, 14 people with T2D took 15 millimoles of magnesium every day for 6 weeks. The researchers found that improving magnesium levels did not improve the participants’ sensitivity to insulin.

In a small 2019 study with 42 participants, researchers found that a group of people who received 250 milligrams (mg) per day of supplemental magnesium for 3 months had reduced insulin resistance and improved blood glucose regulation compared to a control group who did not take any supplements.

In a small 2021 study with 50 participants, researchers looked at 400-mg magnesium citrate supplementation in people with T2D who had unmanaged blood sugar levels. The group who received magnesium supplementation saw a significant drop in HbA1c, a measurement of long-term blood glucose levels.

Currently, there is not enough evidence to support the use of magnesium or any other supplement to manage blood glucose levels in people who have diabetes and do not have nutritional deficiencies.

Various types of magnesium supplements are available, and they vary based on how easy they are to absorb. Options include:

  • magnesium aspartate
  • magnesium carbonate
  • magnesium chloride
  • magnesium citrate
  • magnesium gluconate
  • magnesium glycinate
  • magnesium lactate
  • magnesium oxide
  • magnesium sulfate
  • magnesium taurate
  • magnesium threonate

If a magnesium supplement dissolves well in a liquid, the body can absorb it more easily. According to the ODS, magnesium aspartate, chloride, citrate, and lactate are the easiest to absorb.

Studies on magnesium supplements and their effects on blood glucose regulation often do not compare different forms of magnesium to one another. Some studies, such as the small 2021 study above, state the type of magnesium they used but do not provide a control with a different type of magnesium.

The ODS highlights other small studies that used the following types and amounts of magnesium:

  • 300 or 600 mg daily of magnesium oxide, which improved both magnesium levels and blood glucose regulation
  • 300 mg daily of liquid magnesium chloride, which returned magnesium levels to normal and reduced glucose levels
  • 368 mg daily of magnesium aspartate, which had no effect on blood glucose regulation

Adults over 18 years of age need 310 to 420 mg of magnesium per day, depending on age, sex, and pregnancy status. According to the Academy of Nutrition and Dietetics, getting magnesium from food sources is better for overall health than taking supplements, as foods with magnesium provide other nutrients and more benefits.

Good food sources of magnesium include leafy greens, nuts, seeds, whole grains, and beans, such as:

  • pumpkin seeds
  • chia seeds
  • almonds
  • spinach
  • cashews
  • peanuts
  • fortified cereal
  • soy milk
  • black beans
  • edamame beans
  • peanut butter
  • potatoes
  • rice
  • yogurt
  • oatmeal
  • kidney beans
  • banana
  • salmon
  • milk
  • halibut

Learn more about foods high in magnesium.

Healthy levels of magnesium in the blood are also vital for the following possible functions:

  • regulating blood pressure and reducing a person’s risk of heart disease and stroke
  • maintaining bone strength
  • preventing migraine episodes
  • making glucose more available to the brain during exercise and improving performance, according to a 2017 review
  • reducing depression, anxiety, and stress, according to an 8-week study from 2021

However, more research is necessary to confirm many of these benefits. Maintaining adequate magnesium levels should be part of a balanced approach to nutrition.

Magnesium is unlikely to cause any negative effects when a person consumes it as part of their diet. The kidneys remove excess magnesium through the urine.

However, if a person consumes too much magnesium from supplements, they might experience the following side effects:

Magnesium carbonate, chloride, gluconate, and oxide have most often appeared in reports of diarrhea. Magnesium salts have a laxative effect.

Magnesium toxicity is also possible after taking especially high doses of magnesium-based laxatives or antacids that provide more than 5,000 mg per day. Early symptoms of magnesium toxicity include:

This can progress to breathing difficulties, extremely low blood pressure, an irregular heartbeat, and eventual cardiac arrest. People with kidney problems have a higher risk of magnesium toxicity because their bodies are less able to clear excess magnesium through their urine.

It is advisable to contact a qualified health professional before taking magnesium supplements.

Maintaining adequate magnesium levels might reduce a person’s risk of developing insulin resistance and type 2 diabetes (T2D). Conversely, T2D may lower a person’s blood magnesium levels.

While some studies have shown promising results, the evidence is unclear on whether magnesium supplementation can help regulate blood glucose in people who already have T2D.

No particular type of magnesium supplement has shown more beneficial effects for people with T2D than other types. However, limited research has found that magnesium citrate, chloride, and oxide have improved blood glucose regulation.

People should aim to consume enough magnesium through food and should consult a healthcare professional before taking magnesium supplements.