Magnesium Bisglycinate vs Glycinate: Are They the Same?

TL;DR

They're the same compound. Bisglycinate is the precise name, glycinate is the common one, and diglycinate turns up in the research literature. All three point to one molecule with one CAS number. Nothing about which word a brand prints changes what's in the capsule.

The short answer

Magnesium glycinate and magnesium bisglycinate are two names for a single substance.

Look it up in PubChem, the US National Library of Medicine's chemical database, and you land on one record. Compound ID 84645, molecular formula C4H8MgN2O4, CAS number 14783-68-7. Listed under that one entry you'll find magnesium glycinate, magnesium bisglycinate, magnesium diglycinate, bis(glycinato)magnesium, and magnesium bis(glycinate) (PubChem CID 84645).

One molecule, several names, no difference in what you're taking.

The chemistry, in one paragraph

Magnesium carries a double positive charge, so it pairs with two units of glycine, each carrying a single negative charge. That gives the formula C4H8MgN2O4 and a molecular weight of 172.42 g/mol, with the formal chemical name magnesium bis(2-aminoacetate) (PubChem CID 84645).

The "bis" prefix means two. It's there to specify how many glycine units are attached. Drop the prefix and you get glycinate, which is what most people say and what most labels print.

Why labels differ

Brands pick whichever name they think their customer recognizes, and regulators and researchers use their own conventions.

The United States Adopted Name is magnesium glycinate, which is why that version dominates US supplement labels. European regulatory listings favor bis(glycinato-N,O)magnesium. Medical Subject Headings, the indexing vocabulary behind PubMed, files it under magnesium diglycinate (PubChem CID 84645).

The research follows suit. The clinical study most often cited for this form's gentleness on the gut is titled "Bioavailability of magnesium diglycinate vs magnesium oxide" (Schuette 1994), while the 2025 placebo-controlled sleep trial calls it bisglycinate (Schuster 2025). Same compound, different decade, different house style.

Some brands use bisglycinate because it sounds more technical. That's a marketing choice about a word, not a difference in the ingredient.

What actually varies between products

Three things are worth checking, and none of them is the spelling on the front.

Elemental magnesium. The compound is about 14 percent magnesium by weight, which follows from the formula and molecular weight above. A 1,000 mg dose of magnesium bisglycinate delivers roughly 140 mg of actual magnesium. The supplement facts panel gives you the elemental figure. The front label often gives you the compound weight, and the two numbers look very different. That 14 percent is the pure, anhydrous figure, and many commercial ingredients are hydrated or buffered and run closer to 10 or 11 percent, so trust the panel over the chemistry.

Whether magnesium oxide is in the blend. Check the ingredient list for magnesium oxide alongside the glycinate. A blended product and a fully chelated one are different things, and that distinction is real in a way the bisglycinate-versus-glycinate one isn't.

Dose and split. How much you take and whether you split it through the day affects you more than any naming question.

FAQ

Is bisglycinate better than glycinate?

No, because they're the same thing. Any difference you notice between two products comes from the elemental magnesium dose, whether oxide has been blended in, or how the rest of the formula is put together.

Why do labels use different words then?

Regional convention and brand preference. Magnesium glycinate is the United States Adopted Name, European regulatory entries use the bis(glycinato) form, and PubMed indexes it as diglycinate (PubChem CID 84645).

Which should I buy?

Ignore the name and read the supplement facts panel. Check the elemental magnesium per serving, check whether magnesium oxide appears in the ingredients, and pick a dose you can take consistently. The form's real advantage is that people tolerate it well enough to keep taking it (Schuette 1994).

Does the glycine do anything?

It comes along with the magnesium, and the amount is well below the 3 grams used in glycine sleep trials, so a magnesium supplement is not a glycine dose. More on that in glycine for sleep.

Where to go next

For how this form compares with the other common option, see magnesium glycinate vs citrate. For what the evidence actually supports, see magnesium glycinate benefits. For the full form comparison, see which magnesium is best for sleep and anxiety.

Disclaimer

This article is for general information only. It is not medical advice and it does not replace guidance from a qualified healthcare professional. Magnesium supplements can interact with certain medications, including some antibiotics, bisphosphonates, and diuretics. People with reduced kidney function should not take supplemental magnesium without medical supervision. Do not use this information to diagnose or treat any condition. Speak with your doctor before starting any supplement.