Magnesium bisglycinate and magnesium glycinate are the same compound. Different labels, identical molecule. If you’ve seen both names on supplement packaging and wondered whether you’re buying something different, the short answer is no.
The confusion is understandable — supplement manufacturers aren’t required to use a single standardised name, so the same product can appear under several terms depending on the brand. Here’s what each name actually means, why the variation exists, and what to look for when you’re comparing products.
What Is Magnesium Glycinate?
Magnesium glycinate is magnesium bound to glycine, an amino acid. This process — bonding a mineral to an organic molecule — is called chelation, and it significantly improves how well the magnesium is absorbed in the small intestine compared to inorganic forms like magnesium oxide.
Glycine is also an inhibitory neurotransmitter with its own calming properties. It acts on glycine receptors in the brainstem and spinal cord — a distinct inhibitory system from GABA, though both have calming effects — which is one reason magnesium glycinate is particularly popular for evening use.
For a full explanation of how chelation works and how glycinate compares to other chelated forms, see our guide to chelated magnesium.
What Does “Bisglycinate” Mean?
“Bis” comes from Latin, meaning twice, or two. Magnesium bisglycinate is magnesium bonded to two glycine molecules — one on each side of the magnesium ion.
When magnesium glycinate is fully chelated, it is also bonded to two glycine molecules. The two names describe the same structure.
The term “diglycinate” is occasionally used as well — same compound, third name. None of these variations signal a difference in quality or how the supplement performs.
Why Do Labels Use Different Names?
There’s no UK or EU regulatory requirement to standardise the name on a supplement label. “Magnesium glycinate” is the common name; “magnesium bisglycinate” is the more technically precise version that explicitly describes the two-glycine structure. Both appear in peer-reviewed research and both are used by reputable manufacturers.
Some brands prefer bisglycinate to signal that they’re using the fully chelated form rather than a partial chelate. Others stick with glycinate because it’s more widely recognised by consumers.
In practice, if you’re seeing either term on a supplement label, you’re looking at the same class of product — provided it’s a genuine amino acid chelate and not a blended formula (more on that below).
Is There Any Difference in Absorption?
No meaningful difference in bioavailability has been found between products labelled glycinate and those labelled bisglycinate when both are fully chelated.
What does affect absorption is whether the product is a true amino acid chelate, the dose of elemental magnesium per serving, and whether you take it with food. A 2005 study in Magnesium Research (Coudray et al.) tested ten magnesium compounds in magnesium-depleted rats and found organic chelated forms had significantly higher bioavailability than inorganic forms like magnesium oxide, which showed absorption as low as 4% in some measurements. Human studies point in the same direction, with chelated forms consistently outperforming oxide.
The name on the label — glycinate or bisglycinate — doesn’t change any of that.
The One Exception: “Buffered” Magnesium
Some products marketed as magnesium glycinate are actually buffered — a blend of a chelated form with a cheaper inorganic form, typically magnesium oxide, to reduce manufacturing cost.
This is not the same as a pure bisglycinate or glycinate product. The issue is that manufacturers rarely disclose the ratio of chelated to inorganic magnesium on the label, so you may be getting considerably more oxide than chelate.
To check: look at the ingredients list rather than just the front of the packaging. A pure chelated product will list only “magnesium glycinate”, “magnesium bisglycinate”, or “magnesium bis-glycinate” as the magnesium source — not a combination that includes oxide, hydroxide, or carbonate.
What to Look For When Buying
Whether the label says glycinate or bisglycinate, the same buying criteria apply:
- Elemental magnesium content per capsule. This is the actual amount of magnesium your body can use — not the weight of the whole compound. It should be clearly stated on the label.
- No blending with inorganic forms. The source should be glycinate or bisglycinate only.
- No unnecessary fillers. Magnesium supplements don’t need bulking agents, artificial colours, or anti-caking compounds that could cause digestive issues.
- UK-made or independently tested. Third-party testing confirms you’re getting what’s on the label.
Our Magnesium Glycinate is a pure bisglycinate chelate providing 55mg elemental magnesium per capsule, with no oxide, no artificial fillers, and vegan certification. The name on the front says glycinate — the structure is fully bisglycinate.
FAQ
Q: Is magnesium bisglycinate the same as magnesium glycinate?
A: Yes. Both names refer to the same compound — magnesium bonded to two glycine amino acid molecules. “Bisglycinate” is the more precise term (bis = two), but products labelled “magnesium glycinate” are typically the same fully chelated form.
Q: Is magnesium bisglycinate better than magnesium glycinate?
A: They’re the same molecule, so neither is better than the other. The more relevant question is whether the product is a pure amino acid chelate or a buffered blend that mixes glycinate with cheaper inorganic forms like oxide.
Q: What’s the difference between magnesium diglycinate and bisglycinate?
A: No difference — diglycinate is a third name for the same compound. All three terms (glycinate, bisglycinate, diglycinate) describe magnesium chelated to two glycine molecules.
Q: Does magnesium bisglycinate help with sleep?
A: Magnesium glycinate/bisglycinate may support sleep quality through magnesium’s role in regulating NMDA receptors and glycine’s direct calming action via glycine receptors in the nervous system. For a detailed look at the research, see our post on magnesium for sleep.
Q: Does magnesium bisglycinate cause diarrhoea?
A: Unlike magnesium oxide or high-dose magnesium citrate, bisglycinate/glycinate is unlikely to cause loose stools. Because it’s chelated, the magnesium is absorbed in the small intestine rather than drawing water into the bowel. It’s the form most often recommended for people who’ve had digestive problems with other magnesium supplements. See our post on magnesium side effects for more detail.
References
- Coudray C, et al. (2005). Study of magnesium bioavailability from ten organic and inorganic Mg salts in Mg-depleted rats. Magnesium Research, 18(4), 215–223.
- Bannai M, et al. (2012). The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers. Frontiers in Neurology, 3, 61.
- Schwalfenberg GK & Genuis SJ. (2017). The importance of magnesium in clinical healthcare. Scientifica, 2017, 4179326.
- NHS. Vitamins and minerals — Magnesium.
This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any supplement, especially if you are pregnant, have a medical condition, or take prescription medication.
