Magnesium Glycinate vs Magnesium Bisglycinate: Why They're the Same Thing

Short answer first, since this is the question people are actually typing in: magnesium glycinate and magnesium bisglycinate are not two different forms of magnesium. They're the same compound. One is just a shortened label name for the other.

Here's the chemistry behind it. Magnesium carries a plus-two charge. Glycine, the amino acid doing the chelating, carries a single negative charge per molecule. To balance magnesium's charge, you need two glycine molecules attached to every one magnesium ion. That makes the compound, technically, magnesium bis-glycinate. The "bis" prefix just means two. Somewhere along the way, supplement labels started dropping the "bis" and calling it magnesium glycinate instead. Both names describe the exact same molecule. Neither is more "pure" or more advanced than the other.

This is a narrower question than the one we covered in Magnesium Glycinate vs Bisglycinate vs Citrate: What Are You Actually Buying?. That piece walks through seven different magnesium forms, bisglycinate, citrate, oxide, malate, L-threonate, taurate, and chloride/sulfate, and why the compound actually matters for absorption and digestive effects. This piece deals with something narrower: two different names for the same form. If that post answers "which form should I take," this one answers "wait, are these even different."

Where this confusion causes a real problem is when someone assumes bisglycinate is some newer or more advanced version and pays more for it, or avoids a plainly labeled product thinking it's the lesser form. Neither assumption holds up. What actually varies between magnesium products using this chelate isn't the name on the front of the label, it's the elemental magnesium per serving and whether the full ratio is disclosed, exactly the "elemental magnesium" distinction the other post covers in more depth.

That earlier post names Source Naturals Magnesium Bis-Glycinate as the current pick for daily use, for exactly this reason: a single chelated form with the elemental magnesium content clearly stated, not a blend hiding the ratio. See the full review.

If a product lists "magnesium bisglycinate" and another lists "magnesium glycinate" at the same elemental dose, you're looking at the same thing twice, not a decision to make.