Magnesium bisglycinate, glycinate and chelated magnesium: what the names mean

Magnesium bisglycinate and magnesium glycinate are two names for the same compound. So are magnesium diglycinate and, on many labels, magnesium amino acid chelate. The names are not where products differ. What differs is whether the ingredient is the pure compound, or the compound blended with something else, and an Australian label gives you enough to tell.

The short answer

Magnesium bisglycinate is one magnesium ion bound to two molecules of the amino acid glycine. "Bis" and "di" both mean two, so bisglycinate and diglycinate spell out the structure. "Glycinate" is the shorter everyday name for the same thing. In practice, a supplement labelled magnesium glycinate and one labelled magnesium bisglycinate contain the same compound.

Two other words on labels need more care: "chelated" and "buffered". The first describes a type of structure and does not pin down one compound. The second usually means the glycinate has been mixed with a second, denser form of magnesium.

One compound, four names

Name on the label	What it refers to
Magnesium bisglycinate	Magnesium bound to two glycine molecules. The most precise everyday name.
Magnesium diglycinate	The same compound. Common in older research papers.
Magnesium glycinate	The same compound, by its shorter name.
Magnesium amino acid chelate	Often the same compound, but the name alone does not say which amino acid is used.

The research uses the names interchangeably too. The stable-isotope study most often cited for how this form is absorbed called it magnesium diglycinate. The largest recent trial called it magnesium bisglycinate. Both describe magnesium bound to two glycines.

The compound has the chemical formula C₄H₈MgN₂O₄. Magnesium makes up about 14% of its weight and the two glycines make up the rest. That 14% figure is the key to reading a label, and it comes up again below. Our guide to elemental magnesium explains the arithmetic for every common form.

What "chelated" means

A chelate is a mineral held by an organic molecule that grips it at more than one point, a little like a claw. Glycine binds magnesium through two parts of its structure at once, which is what makes magnesium bisglycinate a chelate. Magnesium oxide, by contrast, is a simple pairing of magnesium and oxygen.

So all magnesium bisglycinate is chelated magnesium. But not all chelated magnesium is bisglycinate. The word describes a kind of bond, not a specific ingredient, and it is used loosely on packaging. A product described only as "chelated magnesium" could contain glycinate, another amino acid chelate, or a mix.

The practical rule is simple: ignore the word "chelated" on the front of the pack and read the ingredient name in the active ingredients panel. That name is what tells you what you are taking.

What "amino acid chelate" means on a label

"Magnesium amino acid chelate" is a real ingredient name, and in many products it is magnesium bisglycinate. The catch is that the name does not specify the amino acid. In one frequently cited trial comparing magnesium forms, the chelate arm is described simply as a magnesium amino acid chelate. That is typical of how the term is used, in research and on packaging.

If the exact compound matters to you, look for "bisglycinate" or "glycinate" in the ingredient name, or check the product's entry on the ARTG. Our guide to searching the ARTG shows how.

What "buffered" means

This is where products really do differ.

Because magnesium is only about 14% of magnesium bisglycinate, getting a meaningful dose takes a lot of powder. Around 2,100 mg of the compound supplies 300 mg of magnesium. That means large capsules or several capsules a day.

A buffered ingredient gets around this by adding a denser form of magnesium, usually magnesium oxide, which is about 60% magnesium by weight. One major manufacturer of magnesium bisglycinate describes its buffered grade as using "an additional excess of magnesium oxide" to raise the magnesium content. The blend carries more magnesium per capsule, but part of that magnesium is now oxide rather than glycinate.

The arithmetic shows how quickly the share shifts. As an illustration, a blend that is 70% bisglycinate and 30% oxide by weight is about 28% magnesium. Roughly two thirds of the magnesium in that blend comes from the oxide, even though the oxide is less than a third of the powder.

That matters because the two forms behave differently. In a randomised trial of 46 healthy adults taking 300 mg of magnesium a day for 60 days, magnesium oxide showed no difference from placebo in urinary magnesium, while an amino acid chelate and magnesium citrate both did. Magnesium that stays unabsorbed in the gut is also the usual cause of loose stools, which is one of the reasons people choose glycinate in the first place. Our guide to magnesium absorption covers why studies comparing forms often disagree, so no single trial settles the question.

None of this makes a buffered product wrong. It is simply a different product from a pure bisglycinate, and worth knowing about when comparing labels.

How to tell from an Australian label

Australian labels for mineral supplements must state both the ingredient and the amount of the mineral element it supplies, usually written as "equivalent to magnesium". Those two numbers are enough for three quick checks.

1. Read every active ingredient. If magnesium oxide, citrate or another magnesium compound is listed alongside the glycinate, the product is a blend. The equivalent figure covers all of them together.
2. Divide the magnesium by the ingredient weight. For a single listed bisglycinate ingredient, the equivalent figure should be about 14% of the ingredient weight, or a little less. For example, 1,000 mg of magnesium bisglycinate would supply about 140 mg of magnesium.
3. Treat a much higher figure as a question. If a single glycinate ingredient appears to supply 20% or more of its weight as magnesium, something denser is likely in the mix. The sponsor named on the label should be able to tell you what the ingredient contains.

A figure a little below 14% is normal. Some ingredients carry water or small amounts of other material, which lowers the share. Our guide to reading a supplement label works through the rest of the panel.

Does the name change anything about the research?

No. Studies of magnesium bisglycinate, magnesium diglycinate and magnesium glycinate are studies of the same compound, and it is reasonable to read them together. The one caution is the reverse case: research on "magnesium amino acid chelate" may or may not be glycinate, and research on magnesium in general is not research on glycinate at all.

For a full picture of how this form is absorbed, what it has been studied for and how it is tolerated, see our magnesium glycinate guide.

When to talk to a doctor or pharmacist

Whatever the name on the label, the same safety points apply. Magnesium supplements can interact with some medicines, including certain antibiotics, osteoporosis medicines and thyroid medicine, and people with reduced kidney function are at greater risk of magnesium building up in the blood. A pharmacist can check a product against anything else you take. Our guide to side effects and interactions covers this in more detail.