Can magnesium supplements help for diabetes? Yes

Can magnesium supplements help for diabetes? Yes

A 2006 meta-analysis looked at nine studies on type 2 diabetics and found that oral magnesium supplements reduce fasting blood sugar and raise the ‘good’ HDL cholesterol in type 2 diabetics, compared to placebo.1

Additionally, people with higher magnesium intake have lower blood sugar and enhanced insulin sensitivity.2

Magnesium supplements can reduce blood sugar and insulin resistance even in people without magnesium deficiency.3

Magnesium is used in about 300 reactions in the body, so it’s important to optimize your magnesium levels for several reasons besides blood sugar control.

Magnesium supplements

Magnesium in supplements is always bound to another substance, such as citrate, oxide, or carbonate. The resulting substance, e.g. magnesium chloride, is referred to as a magnesium salt. Different magnesium salts may vary in absorption, price, as well as other effects.

In humans, magnesium oxide appears to be a poorly absorbed form. Ironically, magnesium oxide is one of the most common forms being sold. Magnesium chloride, magnesium lactate and magnesium aspartate are better.4

A study on magnesium-deficient rats found that all of the following forms were able to correct the deficiency: magnesium oxide, chloride, sulphate, carbonate, acetate, pidolate, citrate, gluconate, lactate, aspartate. The best form was gluconate, while sulphate (MgSO4) was least effective. 5

That said, I think most magnesium supplements are fine. You might want to avoid magnesium oxide, though.

Side effects (partial list): The most common side effects reported are mild abdominal pain (8.7%), diarrhea (6.7%), nausea (2.9%).1 A number of studies reported no severe side effects.1, 6-9 One study found that side effects were common but diminished over time.10 Kidney problems may be a reason to avoid magnesium supplements, so discuss that with your doctor.

Dose: 300-400 milligrams of elemental magnesium per day seems appropriate, based on studies on diabetics. This may seem high, but keep in mind that, typically, only 30-50% of magnesium supplements are absorbed. It can take 3 months for magnesium levels to increase even with supplementation.10 Since diarrhea is a common side effect of magnesium supplements, take them in divided doses during the day. It will reduce that side effect.

Magnesium-rich foods

It is possible to get plenty of magnesium from food, so you may not have to take a supplement if you eat lots of magnesium-rich foods.

Here is a list of magnesium-rich foods that you can increase your intake of, to minimize the need for supplements. As you can see, your best bet is typically nuts, seeds and cocoa products. In fact, only 50 grams (1.8 oz) of pumpkin seeds contain 270 milligrams magnesium.

Foods rich in magnesium

Nuts and seeds

Pumpkin & squash seeds

Brazil nuts

Sunflower seeds

Sesame seeds


Cashew nuts

Peanuts & peanut butter






Cocoa powder

Dark chocolate


Vegetables, fruit, berries


Prickly pears

Note: The foods are listed from most to least magnesium in each category.



  1. Song Y, He K, Levitan EB, Manson JE, Liu S. Effects of oral magnesium supplementation on glycaemic control in Type 2 diabetes: a meta-analysis of randomized double-blind controlled trials. Diabet Med. Oct 2006;23(10):1050-1056.
  2. Hruby A, Ngwa JS, Renstrom F, et al. Higher magnesium intake is associated with lower fasting glucose and insulin, with no evidence of interaction with select genetic loci, in a meta-analysis of 15 CHARGE Consortium Studies. J Nutr. Mar;143(3):345-353.
  3. Mooren FC, Kruger K, Volker K, Golf SW, Wadepuhl M, Kraus A. Oral magnesium supplementation reduces insulin resistance in non-diabetic subjects – a double-blind, placebo-controlled, randomized trial. Diabetes Obes Metab. Mar;13(3):281-284.
  4. Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnes Res. Dec 2001;14(4):257-262.
  5. Coudray C, Rambeau M, Feillet-Coudray C, et al. Study of magnesium bioavailability from ten organic and inorganic Mg salts in Mg-depleted rats using a stable isotope approach. Magnes Res. Dec 2005;18(4):215-223.
  6. Lee S, Park HK, Son SP, Lee CW, Kim IJ, Kim HJ. Effects of oral magnesium supplementation on insulin sensitivity and blood pressure in normo-magnesemic nondiabetic overweight Korean adults. Nutr Metab Cardiovasc Dis. Dec 2009;19(11):781-788.
  7. Yokota K, Kato M, Lister F, et al. Clinical efficacy of magnesium supplementation in patients with type 2 diabetes. J Am Coll Nutr. Oct 2004;23(5):506S-509S.
  8. Guerrero-Romero F, Tamez-Perez HE, Gonzalez-Gonzalez G, et al. Oral magnesium supplementation improves insulin sensitivity in non-diabetic subjects with insulin resistance. A double-blind placebo-controlled randomized trial. Diabetes Metab. Jun 2004;30(3):253-258.
  9. Rodriguez-Moran M, Guerrero-Romero F. Oral magnesium supplementation improves insulin sensitivity and metabolic control in type 2 diabetic subjects: a randomized double-blind controlled trial. Diabetes Care. Apr 2003;26(4):1147-1152.
  10. Eibl NL, Kopp HP, Nowak HR, Schnack CJ, Hopmeier PG, Schernthaner G. Hypomagnesemia in type II diabetes: effect of a 3-month replacement therapy. Diabetes Care. Feb 1995;18(2):188-192.