Magnesium Bisglycinate vs Glycinate: Is There a Difference?

Is magnesium bisglycinate the same as glycinate? Yes. Magnesium bisglycinate and magnesium glycinate are two names for one compound: a magnesium atom bound to two molecules of the amino acid glycine. What differs between products is whether they are fully reacted or buffered with magnesium oxide, and how much elemental magnesium each serving gives. This guide covers what to check on the label, what the research on magnesium bisglycinate shows, how much to take, when to take it, and side effects.

It is educational, not medical advice.

Key Takeaways

• Magnesium bisglycinate and magnesium glycinate are the same compound. Both names describe one magnesium atom bound to two molecules of the amino acid glycine. You may also see magnesium diglycinate or magnesium glycinate chelate.
• The real difference is on the label: whether the product is fully reacted (pure bisglycinate) or buffered (mixed with magnesium oxide), and how much elemental magnesium each serving gives you.
• Pure magnesium bisglycinate is about 14 percent magnesium by weight, so 100 mg of magnesium takes about 710 mg of the compound.
• In a 4-week randomized trial, 250 mg of magnesium a day as bisglycinate improved sleep scores more than placebo in adults who reported poor sleep.
• Stay within 350 mg a day of magnesium from supplements, the adult upper limit. Food magnesium does not count toward it.

Is Magnesium Bisglycinate the Same as Glycinate?

Yes. Magnesium bisglycinate is the chemical name, and magnesium glycinate is the common name for the same thing. "Bis" means two: each magnesium atom is held by two glycine molecules, forming what is called a chelate. The formula is the same whichever name is on the front of the bottle.

Name on the label	What it means
Magnesium bisglycinate	Chemical name: magnesium bound to two glycine molecules
Magnesium glycinate	Common name for the same compound
Magnesium diglycinate	Another name for the same compound
Magnesium glycinate chelate	Same compound; "chelate" describes the ring-shaped bond
Buffered magnesium glycinate	Magnesium glycinate blended with another form, usually magnesium oxide

So when you compare magnesium bisglycinate vs glycinate, you are not comparing two forms. You are comparing two products, and the details below are what set them apart.

Glycine, the amino acid in both forms, has its own research on sleep and glutathione; see glycine benefits.

What Actually Differs: Fully Reacted vs Buffered

• Fully reacted (non-buffered). All of the magnesium is bound to glycine. Labels may say "fully reacted", "100% chelated" or "non-buffered".
• Buffered. Magnesium glycinate is blended with magnesium oxide. Oxide carries more magnesium per gram, so buffering lets a capsule hold more magnesium, but part of that magnesium is no longer glycinate. The label may list both forms, for example "as magnesium bisglycinate and magnesium oxide".
• Elemental magnesium. The Supplement Facts panel lists the milligrams of magnesium itself, not the weight of the compound. That number is the one to compare between products and to count toward the 350 mg limit.

The 14 percent math

Magnesium makes up about 14 percent of the weight of magnesium bisglycinate; glycine makes up the rest. That is why chelated magnesium capsules are large, or come as two or more capsules per serving. As a rough guide, 100 mg of magnesium takes about 710 mg of fully reacted magnesium bisglycinate, and 200 mg takes about 1,420 mg. A product that claims much more magnesium per capsule than this is likely buffered.

Magnesium Bisglycinate Benefits

Magnesium is a cofactor in more than 300 enzyme systems. It supports protein synthesis, muscle and nerve function, blood sugar control, blood pressure regulation, energy production and bone development, and it helps move calcium and potassium across cell membranes (NIH ODS: Magnesium). Yet about 48 percent of Americans get less magnesium from food and drinks than they need (NIH ODS: Magnesium).

• Sleep. In a randomized, double-blind trial of 155 healthy adults aged 18 to 65 who reported poor sleep, 250 mg of magnesium a day as bisglycinate improved scores on a standard sleep questionnaire more than placebo over 4 weeks. The benefit was modest overall and larger in people who got less magnesium from their diet (Schuster et al., 2025).
• Gentle on the stomach. Too much supplemental magnesium can cause diarrhea, and the forms most often reported to cause it are carbonate, chloride, gluconate and oxide (NIH ODS: Magnesium). Glycinate is not on that list, which is one reason many people choose it.
• Vitamin D. The enzymes that process vitamin D appear to need magnesium. See vitamin D and magnesium: can you take them together?

For a fuller look at what the mineral is good for, see magnesium glycinate benefits.

How Much Magnesium Bisglycinate Should You Take?

Adults	Men	Women
Age 19 to 30	400 mg	310 mg
Age 31 and older	420 mg	320 mg
Upper limit from supplements	350 mg	350 mg

Source: NIH ODS: Magnesium. The daily amounts are totals from food and supplements. The 350 mg upper limit applies only to magnesium from supplements and medicines, not to food. The sleep trial above used 250 mg a day. Follow your product label, and count the elemental magnesium, not the weight of the bisglycinate.

When to Take Magnesium Bisglycinate

• Evening is popular, and it fits the sleep research, but any time you will remember works.
• With a meal if you notice any stomach upset.
• Split larger amounts into two servings if you prefer.
• Space it from certain medicines (see below).

For dose and timing aimed at sleep, see magnesium glycinate for sleep.

For diarrhea, how much is too much and who should check first, see magnesium glycinate side effects.

Side Effects and Who Should Check First

• Too much: high amounts of supplemental magnesium often cause diarrhea, sometimes with nausea and cramping. Stay within 350 mg a day from supplements unless your clinician advises otherwise (NIH ODS: Magnesium).
• Kidney problems: talk with your clinician before taking magnesium supplements, because the kidneys remove extra magnesium.
• Bisphosphonates: take them at least 2 hours before or after magnesium (NIH ODS: Magnesium).
• Tetracycline and quinolone antibiotics: take them at least 2 hours before or 4 to 6 hours after magnesium (NIH ODS: Magnesium).
• Diuretics and proton pump inhibitors: some diuretics and long-term use of proton pump inhibitors change magnesium levels, so ask your clinician about magnesium if you take them (NIH ODS: Magnesium).

Our coming-soon Melatonin-Free Sleep Powder uses fully reacted magnesium bisglycinate for half of its 200 mg of magnesium per scoop, with magnesium glycerophosphate for the other half, plus 3 g of glycine and no added melatonin.

Magnesium Glycinate vs Bisglycinate for Long-Term Use

Because magnesium glycinate and magnesium bisglycinate are the same compound, there is no difference between them for long-term use. What matters over months and years is the total amount of magnesium you take from supplements. The adult upper limit is 350 mg a day of supplemental magnesium. Magnesium from food does not count toward it, because in healthy people the kidneys clear the extra in urine. The risk of magnesium building up is higher when the kidneys do not work well, which is why people with kidney problems should check with a clinician first. If you take a diuretic, or have taken a proton pump inhibitor for more than a year, ask your clinician whether your magnesium level should be checked, since these medicines can change it (NIH ODS: Magnesium).

Glycinate is sometimes paired with magnesium glycerophosphate; our guide to magnesium glycerophosphate vs glycinate compares the two forms side by side.

How Glycinate Compares With Other Forms

Forms that dissolve well in liquid, such as citrate, lactate, aspartate and chloride, are absorbed more completely than magnesium oxide and sulfate (NIH ODS: Magnesium). Glycinate is chosen mostly for being gentle on the stomach. Malate, bound to malic acid, is another option; see magnesium malate for energy, sleep, and recovery. The same glycine chelate is used for other minerals too, such as zinc bisglycinate.

For a side-by-side look at glycinate vs citrate, oxide, threonate and malate, see our magnesium forms comparison.

Coming soon from Synchronicity: our Vitamin D Cofactor Capsules give magnesium 100 mg as fully reacted magnesium bisglycinate, with zinc 10 mg and boron 3 mg per 2 capsules. Join the waitlist on the product page to hear when they launch; no payment is taken.

For vitamin D itself, our Vitamin D3 + K2 Drops are available now; vitamin D and magnesium explains how the two nutrients work together.

The same naming question comes up with zinc; see zinc picolinate vs bisglycinate vs gluconate for how those forms compare. For magnesium oxide side by side with glycinate, see our guide to magnesium glycinate vs oxide.

Sources

• NIH Office of Dietary Supplements. Magnesium: Fact Sheet for Health Professionals. NIH ODS
• Schuster J et al. Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nature and Science of Sleep, 2025. DOI
• Bannai M, Kawai N. New therapeutic strategy for amino acid medicine: glycine improves the quality of sleep. Journal of Pharmacological Sciences, 2012. PubMed
• Kumar P et al. Supplementing glycine and N-acetylcysteine (GlyNAC) in older adults improves glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, physical function, and aging hallmarks: a randomized clinical trial. Journals of Gerontology Series A, 2023. PubMed

Frequently Asked Questions

Is magnesium bisglycinate the same as magnesium glycinate?

Yes. They are two names for the same compound: magnesium bound to two glycine molecules. Differences between products come from buffering and the amount of elemental magnesium per serving.

Which is better, magnesium glycinate or bisglycinate?

Neither, since they are the same compound. Compare products instead: look for "fully reacted" or "non-buffered" if you want pure glycinate, and compare the milligrams of elemental magnesium.

What is magnesium bisglycinate?

A form of magnesium in which each magnesium atom is bound to two molecules of the amino acid glycine. It is about 14 percent magnesium by weight.

What are the benefits of magnesium bisglycinate?

It supplies magnesium, which more than 300 enzyme systems rely on, in a form that is gentle on the stomach. In a 4-week trial, 250 mg of magnesium a day as bisglycinate improved sleep scores more than placebo in adults who reported poor sleep.

What does buffered magnesium glycinate mean?

Magnesium glycinate blended with another form, usually magnesium oxide, to fit more magnesium into each capsule. Part of the magnesium is then oxide rather than glycinate.

How much magnesium bisglycinate should I take?

Adults need 310 to 420 mg of magnesium a day from food and supplements combined. Keep supplemental magnesium within 350 mg a day, and follow your product label.

Does magnesium bisglycinate have side effects?

Too much supplemental magnesium can cause diarrhea, nausea and cramping. Glycinate is not among the forms most often reported to cause diarrhea. People with kidney problems should check with their clinician first.

Can I take magnesium bisglycinate at night?

Yes. Many people take it in the evening, and the sleep trial above used a daily dose. Choose a time you will keep.

Is glycine the same as glycinate?

No. Glycine is an amino acid. Glycinate is the name used when glycine is bound to a mineral, as in magnesium glycinate or zinc glycinate. A magnesium glycinate supplement gives you both magnesium and glycine: by weight, it is about 14 percent magnesium, and glycine makes up the rest. A plain glycine supplement gives you the amino acid with no magnesium.

Is it safe to take magnesium glycinate long term?

For healthy adults, the key is staying within 350 mg a day of magnesium from supplements, the adult upper limit. Magnesium from food does not count toward it. People with kidney problems, and anyone taking diuretics or long-term proton pump inhibitors, should check with a clinician. The long-term picture is the same whether the label says glycinate or bisglycinate.

Why do some labels say bisglycinate and others say glycinate?

It is a naming choice. Bisglycinate is the chemical name that spells out the two glycine molecules, while glycinate is the shorter common name. Neither name tells you whether the product is fully reacted or buffered, so check the Supplement Facts panel for the forms listed and the milligrams of elemental magnesium per serving.

Is magnesium bisglycinate absorbed better than glycinate?

The name alone makes no difference, because they are the same compound. What can change between products is the form mix. A fully reacted product gives all of its magnesium as glycinate. A buffered product gives part of it as magnesium oxide, and NIH notes that magnesium oxide is absorbed less completely than several other forms of magnesium.

These statements have not been evaluated by the Food and Drug Administration. This content is for education and is not medical advice. Our products are not intended to diagnose, treat, cure or prevent any disease. Talk with a healthcare provider before starting a new supplement if you are pregnant, breastfeeding or taking medication.