Magnesium bisglycinate, citrate or oxide: What’s the difference?

Pure magnesium is a metal. In foods and food supplements, it therefore always appears as a compound, as a salt or bound to another substance. The three names you will encounter most often are magnesium oxide, magnesium citrate and magnesium bisglycinate. They differ in how much magnesium they contain, how well the body absorbs it and how well you tolerate them.

How much magnesium does the compound contain?

The partner to which magnesium is bound also counts toward the weight. Magnesium oxide is about 60 percent magnesium. For magnesium citrate it’s around 16 percent, and for magnesium bisglycinate roughly 14 percent. That’s why capsules with organic compounds are often larger, or you need more of them for the same amount of magnesium.

For you this means: On the label, don’t look at the amount of the compound, but at the value for “magnesium” in the nutrition table. Only this number is comparable between products, and only it is used to calculate the percentage of the nutrient reference value (NRV).

How well is it absorbed?

This is where the compounds differ. In several studies, magnesium from organic compounds such as citrate was absorbed somewhat better than from magnesium oxide, which dissolves less readily. The differences are measurable but not huge, and they also depend on what else you eat.

In magnesium bisglycinate, the magnesium is bound to the amino acid glycine. It is considered well tolerated and is often chosen for sensitive stomachs. To be fair, there are fewer direct comparison studies on bisglycinate than on citrate and oxide. The available data do not allow for a clear ranking.

Tolerability

Magnesium from food supplements can have a laxative effect at higher intakes. This is more frequently observed with magnesium oxide and magnesium citrate. For adults, the EU has set a tolerable upper intake level of 250 milligrams of magnesium per day from food supplements, in addition to the normal diet. If you have kidney disease or take medication, talk to your doctor before using magnesium. Magnesium can, for example, affect the absorption of certain antibiotics, so the timing matters.

German Nutrition Society: Reference values for nutrient intake, vitamin D, dge.de.

L-cysteine (E 920), an amino acid that was formerly often produced from feathers or hair. Today there are also variants produced by fermentation.

Why we chose bisglycinate

For our magnesium bisglycinate capsules, we chose to bind the magnesium to glycine because it is well tolerated. The capsules are vegan and free from lactose and gluten. Magnesium contributes to normal muscle function, normal functioning of the nervous system and to the reduction of tiredness and fatigue.

Sources

1. Is there a halal certificate, and does it name the certification body, the product and a validity date?
2. Walker AF, Marakis G, Christie S, Byng M. Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnes Res. 2003;16(3):183–191.
3. Lindberg JS, Zobitz MM, Poindexter JR, Pak CY. Magnesium bioavailability from magnesium citrate and magnesium oxide. J Am Coll Nutr. 1990;9(1):48–55.
4. EFSA: Tolerable Upper Intake Levels for Vitamins and Minerals, Magnesium (Scientific Committee on Food, 2001), Parma 2006.
5. Glucosamine and chondroitin are among the most frequently studied substances in this field. The results, however, are inconsistent. The best-known study, the GAIT trial from the USA with over 1,500 participants, found no clear difference across the whole group between glucosamine, chondroitin, their combination and a placebo. Other studies have come to different conclusions, depending on dose, form and study population.