Magnesium glycinate vs bisglycinate: same compound?

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In chemistry, yes: magnesium glycinate and magnesium bisglycinate are two names for one compound, a magnesium ion bound to two glycine units (formula C4H8MgN2O4, 172.42 g/mol). PubChem files both names, and "diglycinate", under a single record. What differs between labels is what else is in the capsule. A ceiling of 14.1% magnesium by weight gives you a quick check on a label's numbers.

We sell a three-form magnesium capsule that includes bisglycinate, Satiovex Tri-Mag Night, so we have an interest in this question. Nothing below is advice on what to take. It is arithmetic and attributed reports, with our own label as the example.

Are magnesium glycinate and bisglycinate the same compound?

PubChem, the chemistry database run by the US National Library of Medicine, resolves "magnesium glycinate", "magnesium bisglycinate" and "magnesium diglycinate" to one record, compound 84645. Its systematic name is magnesium bis(2-aminoacetate): one magnesium and two glycine-derived units. "Bis" is the chemist's prefix for "two of these", so the longer name spells out the ratio the shorter one leaves implied.

Different bodies use different names for it:

Name Where we saw it
Magnesium bisglycinate The EU list of mineral substances for food supplements published with Regulation (EC) No 1170/2009; a PubChem synonym
Magnesium glycinate The title of the PubChem record, where it is also tagged as a US Adopted Name and a WHO Drug Dictionary entry
Magnesium diglycinate A PubChem synonym, and the wording in the title of a 1994 trial discussed below

The working: why bisglycinate is at most 14.1% magnesium

Use these rounded standard atomic weights: H 1.008, C 12.011, N 14.007, O 15.999, Mg 24.305. Glycine weighs 75.067; losing one hydrogen to bond leaves a glycinate unit of 74.059. Two units make 148.118, and one magnesium adds 24.305, giving 172.423 g/mol, which matches PubChem's 172.42. Magnesium's share is 24.305 / 172.423 = 14.096%, about 14.1%.

That is the anhydrous figure, and it is a ceiling, not a typical value. PubChem also lists a hydrate, and water adds weight without adding magnesium. With two waters per formula unit, as an illustration, the share would fall to about 11.7% (24.305 / 208.453).

What does "chelate" mean on a label?

In chemistry a chelate is a compound in which one molecule grips a metal at two or more points. PubChem's synonym bis(glycinato-N,O)magnesium names those points for bisglycinate: the nitrogen and one oxygen of each glycinate. So "bisglycinate chelate" describes the bonding. It is not an extra ingredient.

As a rule for supplement labels, we found no definition. The only formal one we located is for animal feed: the Association of American Feed Control Officials (AAFCO) wording, as quoted in a 2002 review for the USDA National Organic Program. It covers the product of reacting a metal ion from a soluble salt with amino acids, at one mole of metal to one to three moles of amino acid (preferably two), forming coordinate covalent bonds. So it is not a supplement-labelling rule, and because it allows ratios other than two, "chelate" alone does not tell you the compound is bisglycinate.

What does "buffered" mean?

We found no definition of "buffered" for magnesium supplements in the EU texts we read, the NIH fact sheet or the NIH label database. The database does show how labels use the word. On 10 October 2026 we searched it for buffered magnesium glycinate. Some records print "buffered with magnesium oxide" beside a bisglycinate chelate. Others print "buffered" and name no buffer. The word also appears on vitamin C and creatine labels, so it is a general trade term. The database records what labels say, including labels no longer on the market. It is not a definition.

The arithmetic shows why the oxide matters. Magnesium oxide is 60.3% magnesium (24.305 / 40.304), more than four times bisglycinate's 14.1%. A mix of 76.4% bisglycinate and 23.6% oxide by weight comes to 25.0% magnesium (0.764 x 14.096 + 0.236 x 60.304). That is a sum, not a description of any product. Our guide to magnesium oxide vs citrate vs glycinate covers the other forms.

The ceiling test: can this number be bisglycinate alone?

Take two numbers from a label: the milligrams of the glycinate or bisglycinate compound, and the milligrams of elemental magnesium it is meant to supply. Divide elemental by compound. If the answer is above 14.1%, something else is supplying magnesium.

Invented label line Compound (mg) Elemental (mg) Share What it tells you
A 400 56 14.0% Within the ceiling; consistent with bisglycinate alone
B 400 100 25.0% Above the ceiling; another magnesium source is in the blend
C 1,000 200 20.0% Above the ceiling; about 12.8% oxide by weight would account for it

Run it the other way for a target. To supply 200 mg of elemental magnesium from bisglycinate alone you need at least 1,419 mg of compound (200 / 0.14096). A capsule claiming 400 mg of compound can hold at most about 56 mg (400 x 0.14096 = 56.4).

Three limits apply. The test assumes the one-to-two compound described above. A result below the ceiling does not prove a product is bisglycinate alone, because water, a carrier or a lower-share form could explain it. And it needs a label that states both figures. If either is missing, ask the seller. Our guide to elemental magnesium on a supplement label covers the rest of the panel.

How to spot a blend on a label

  • A second magnesium compound in the "as" bracket or the ingredient list: oxide, citrate, hydroxide or carbonate.
  • The words buffered, complex or blend next to the form name.
  • An elemental figure that fails the ceiling test.
  • A compound weight that is missing, so the test cannot be run.
  • A trademarked ingredient name instead of the chemical name, which the ceiling test needs.

What NIH says about glycinate, and what it does not

The NIH Office of Dietary Supplements fact sheet on magnesium (updated 6 January 2026) says supplements contain different forms of magnesium and that absorption varies. It names aspartate, citrate, lactate and chloride as tending to have higher bioavailability than oxide and sulfate, and says the Supplement Facts panel declares elemental magnesium, not the weight of the whole compound. We searched the page text for "glycin" and "chelat" and found no hit. The fact sheet does not discuss glycinate or bisglycinate, so we cannot report what NIH thinks of it.

One older trial studied the compound under the name diglycinate. Schuette and colleagues (JPEN, 1994) ran a double-blind, randomised crossover trial in 12 patients who had undergone ileal resection. They compared a 100 mg dose of magnesium labelled with the isotope 26Mg, given as the chelate and as oxide. Across the group, absorption was low and similar: 23.5% and 22.8%. In the four patients who absorbed oxide worst, it was 23.5% from the chelate against 11.8% from oxide (p < .05). The limits are plain: 12 people with one surgical history, one small dose, and no result for people in general. The PubMed record lists US public funding. We read the abstract only.

Our label as the example

Satiovex Tri-Mag Night is a three-form magnesium capsule: magnesium bisglycinate, magnesium L-threonate and magnesium taurate, 200 mg of elemental magnesium per serving of three capsules, 90 capsules, 30 servings. The label facts on the product page also list no magnesium oxide and no magnesium citrate.

The single-form ceiling does not apply directly, because the three forms carry different shares of magnesium: bisglycinate 14.1%, taurate about 8.9% (24.305 / 272.573) and L-threonate about 7 to 8% (8.3% anhydrous, 7.8% as the monohydrate). A blend cannot hold a higher share than its richest ingredient, so if those three are the only sources of the 200 mg, it cannot exceed 14.1%. The three compounds together must then weigh at least 1,419 mg per serving (200 / 0.14096), whatever the split, and hydration would only add to that. The full test needs the weight of each form. This page uses only the elemental total and the form names.

If you are weighing a blend against a single form, triple magnesium complex vs magnesium glycinate sets out what to compare.

Questions about glycinate and bisglycinate

Is magnesium bisglycinate the same as magnesium glycinate?

Chemically yes. PubChem records both names, and magnesium diglycinate, under one compound. Labels can still differ in what else is in the product, which is what the ceiling test checks.

What does buffered magnesium glycinate mean?

We found no definition. In the NIH label database some records print "buffered with magnesium oxide" and others name no buffer, so read the ingredient lines and run the ceiling test rather than relying on the word.

Does chelated mean better absorbed?

Chelated describes how the magnesium is bonded to the glycine. It is not an absorption claim, and the studies we read disagree. The 1994 trial above found an advantage over oxide only in the four patients who absorbed oxide worst. In a 2024 crossover study of 40 healthy adults, funded by an ingredient company that employs two of its authors and built around a different magnesium ingredient, plasma magnesium did not rise significantly after bisglycinate over six hours, but did at one time point each after oxide and citrate. The NIH fact sheet does not discuss chelates. We offer no rule.

How much magnesium is in 400 mg of magnesium glycinate?

At most about 56 mg: 400 x 24.305 / 172.423 = 56.4 mg, if the 400 mg is bisglycinate and nothing else. A hydrate, or an ingredient with a carrier, holds less.

Who should ask a doctor or pharmacist before taking magnesium?

NIH says people who take medicines regularly should discuss their magnesium intake with a health care provider, and lists oral bisphosphonates, tetracyclines and quinolone antibiotics as examples of interactions. It adds that the risk of magnesium toxicity rises with impaired kidney function. Our product page tells anyone who is pregnant, breastfeeding, has kidney problems or takes medication to consult a doctor, and not to exceed the recommended daily dose.

Check your own label

Pick any magnesium label, find the compound weight and the elemental figure, and divide. To hold ours to the same sum, the 90-capsule bottle has its own page, and the FAQ covers delivery and returns.

How we checked this page

  • Sources opened. On 10 October 2026 we read each source listed below and wrote from those pages, not from memory. The NIH Office of Dietary Supplements site refused automated access, so we read the Internet Archive copy of its fact sheet captured on 7 October 2026. We searched the NIH label database through its public interface and read the PubMed records for two trials.
  • What we could not find. A definition of "buffered" or "chelate" written for supplement labels, any NIH statement on glycinate, and the full text of either trial.
  • Review. No clinician (doctor, pharmacist or dietitian) has reviewed this page. It is general information, not medical advice.
  • Who we are. Satiovex products are sold by Xinop LLC, trading as Satiovex. We run this site and have a financial interest in the products.
  • Testing. This page does not claim independent testing for any product we sell.
  • Corrections. Spotted an error? Tell us through the contact page and we will check it.

Last updated 10 October 2026 by the Satiovex editorial team.

Sources

This guide is general information about a food supplement, not medical advice. Adults 18+.