Glycinate vs Bisglycinate: Are They the Same Thing?

Jasmine Meagher, BSc Food Science and Nutrition

Founder, Ritua · 5 min read

Walk down the supplement aisle of any Australian pharmacy and you will find the same ingredient spelled three different ways. Magnesium glycinate on one pack, magnesium bisglycinate on the next, magnesium diglycinate on a third. Shoppers reasonably assume these are three products with three different specifications.

They are not. This is a short article because the answer is short, but there is a second question tucked underneath it that is worth more of your attention, and a labelling practice at the end that actually does change what you are buying.

The short answer

Magnesium glycinate and magnesium bisglycinate are the same compound. So is magnesium diglycinate. They are three names for one molecule, and the chemical databases treat them as such.

Magnesium glycinate, magnesium diglycinate and bis(glycinato-N,O)magnesium are all listed as names for a single compound: C4H8MgN2O4, molecular weight 172.42, CAS number 14783-68-7.

— Magnesium glycinate, CID 84645, PubChem, NIH National Library of Medicine

One CAS number means one substance. If two packs name the same compound, the spelling on the front is not the thing separating them.

Where the bis comes from

Bis is a counting prefix from chemical naming. It means two, and it is used instead of di when the thing being counted already has a complicated name of its own. So bisglycinate is simply the precise way of saying two glycines, and diglycinate is the informal way of saying the same thing.

Two is not an arbitrary number. Magnesium carries a charge of positive two, and each glycinate molecule carries a charge of negative one, so it takes exactly two of them to balance the books. A stable neutral magnesium glycinate molecule cannot be anything other than one magnesium to two glycines.

Which means glycinate without the prefix is not a weaker or cheaper version. The two is implied by the chemistry whether the label spells it out or not.

Is glycine the same as magnesium glycinate?

This is the question I get more often than the spelling one, and here the answer is no. They are genuinely different things.

Glycine is an amino acid on its own, with no magnesium in it at all. It is the smallest of the amino acids, your body makes some of its own, and you get more from collagen rich foods. A 2013 review in Amino Acids classifies it as conditionally essential, meaning the body can produce it but not always in the amounts it needs. It is sold as its own supplement, usually in gram doses.

Magnesium glycinate is a magnesium supplement that happens to use glycine as the delivery vehicle. The quantity of glycine involved is small, and it is not the point of the product.

Worth being blunt about, because some marketing borrows research done on gram doses of standalone glycine and presents it as though it applies to the trace of glycine riding along in a magnesium capsule. It does not.

Why Australian labels use both

Both spellings sit on the Australian Register of Therapeutic Goods right now, on products from different sponsors, and both are acceptable. There is no Australian rule that forces one over the other.

In practice the choice is a marketing one. Bisglycinate sounds more technical and more premium, so brands positioning on formulation credentials tend to use it. Glycinate is shorter, more familiar and easier to search for, so brands positioning on accessibility tend to use that. We use glycinate on the front of the pack for exactly that reason, and the ARTG listing is AUST L 525405 if you want to check it.

What the chelate actually changes

Since the naming does not separate products, it is fair to ask what the chelate is doing at all.

The most direct human evidence is a double blind randomised crossover trial published in JPEN in 1994, which compared an isotope labelled glycinate chelate against magnesium oxide in 12 patients who had undergone bowel resection. Across the whole group the two were almost identical. In the four patients with the most impaired absorption the chelate did roughly twice as well, it reached the blood significantly sooner, and every patient tolerated it better.

The authors' explanation is the interesting part. They concluded that some portion of the chelate is absorbed intact, most likely through a dipeptide transport pathway, rather than having to compete for mineral absorption. That is the mechanism behind the gentleness reputation, and it is a narrower finding than the marketing around it suggests. There is more on how the forms compare in our guide to magnesium forms.

The word that does change what you get

Here is the one to actually look for. Not bis. Buffered.

A fully reacted chelate is only about 14 per cent magnesium by weight, which is awkward for a manufacturer, because it takes a lot of powder to reach a respectable number on the label. The industry solution is a buffered chelate. Balchem, one of the main global suppliers of the raw material, describes its buffered form plainly: it uses an additional excess of magnesium oxide alongside the chelate to lift the elemental magnesium value.

That is a legitimate ingredient and it is disclosed at the raw material level. The issue is what happens downstream. A finished product made with buffered material can still be marketed as magnesium bisglycinate, while a meaningful share of the magnesium in the capsule is actually oxide, which is the form the absorption research treats least kindly.

So if you are comparing two packs, the spelling tells you nothing and the word buffered tells you a lot. Ritua uses a single active ingredient and no buffering, which is why our elemental figure is 100 mg per capsule rather than a larger one. Label reading in the gummy aisle has its own traps, which we go through in magnesium gummies vs capsules.

The bottom line

Glycinate, bisglycinate and diglycinate are one compound with three names, and no brand is giving you something different by choosing one of them. Glycine on its own is a different product entirely.

What separates two magnesium products is the elemental magnesium per serve, whether the chelate has been buffered with a cheaper form, and whether the label tells you either of those things without you having to ask. Our buyer's guide runs through the rest of that checklist, and if you want the full picture on the molecule itself, start with what magnesium glycinate actually is.

For what it is worth, Ritua Magnesium Glycinate states both the compound weight and the elemental weight on the pack. That is the minimum a label should do, not a feature. There is also a 7 night trial pack if you would rather test a week than commit to 120 capsules.

This article is general information, not medical advice, and is not a substitute for guidance from your doctor, particularly if you are managing an existing health condition, are pregnant or breastfeeding, have reduced kidney function, or are taking medication.

Jasmine Meagher

BSc Food Science and Nutrition · Founder, Ritua

Jasmine founded Ritua to bring evidence-based, TGA-compliant supplements to Australian women. She writes about the research behind every ingredient Ritua sells.

Frequently asked questions

Sources

• Magnesium glycinate, CID 84645. PubChem, NIH National Library of Medicine.
• Bioavailability of magnesium diglycinate vs magnesium oxide in patients with ileal resection. JPEN Journal of Parenteral and Enteral Nutrition, 1994.
• Glycine metabolism in animals and humans: implications for nutrition and health. Amino Acids, 2013.
• Magnesium Bisglycinate Chelate, product information. Balchem Human Nutrition and Health.
• Magnesium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements.