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Magnesium glycinate and magnesium citrate are the two forms people compare most. Both are popular, both are easy to find, and the labels make similar promises. But they are not interchangeable, and the right one depends on why you are taking it.
We read the NIH Office of Dietary Supplements fact sheet on magnesium, the MedlinePlus entry on magnesium citrate and the latest sleep trial, then compared the best-selling bottles. For the sleep question in more depth, see our guide to magnesium for sleep.
We research, we don’t lab-test. Everything below comes from the sources listed at the end and the product listings, checked in October 2026.
In this guide:
- The Short Answer
- Magnesium Glycinate vs Citrate vs Oxide, Compared
- What Is the Difference?
- Which Is Better for Sleep and Calm?
- Which Is Better for Constipation?
- What About Magnesium Oxide?
- How Much Is Safe?
- Can You Take Both?
- Our Picks
- Our Verdict
- Frequently Asked Questions
The Short Answer
Take magnesium glycinate for sleep and calm, and magnesium citrate if you want help with occasional constipation. Citrate is well absorbed, according to the NIH, but it is also sold as a laxative, so it can loosen your stools. Glycinate is the form used in the best recent sleep trial. Whichever you choose, stay at or under 350 mg a day from supplements. Our picks: Nature Made Magnesium Glycinate and Nature Made Magnesium Citrate. For every other type, see our types of magnesium chart.
Worried about loose stools, nausea or interactions? Our guide to magnesium glycinate side effects covers what is normal, what is not and who should avoid it.
Magnesium Glycinate vs Citrate vs Oxide, Compared
| Glycinate | Citrate | Oxide | |
|---|---|---|---|
| What it is | Magnesium bound to glycine, an amino acid | Magnesium bound to citric acid | Magnesium bound to oxygen |
| Absorption | Not ranked by the NIH; makers sell it as well absorbed | Absorbed more completely than oxide (NIH) | Absorbed less completely (NIH) |
| Effect on your gut | Usually sold as gentle on the stomach | Can loosen stools; also sold as a laxative | Can loosen stools |
| Best for | Sleep, calm, everyday use | Occasional constipation, general use | Low cost |
| Sleep evidence | Best of the three (2025 trial) | Not tested the same way | Not tested the same way |
What Is the Difference?
Supplements bind magnesium to another compound. That partner changes how well the magnesium dissolves, how much your body absorbs, and how your gut reacts.
The NIH Office of Dietary Supplements says forms that dissolve well in liquid, including citrate, are absorbed more completely than magnesium oxide. Glycinate (often labeled bisglycinate) binds magnesium to the amino acid glycine. The NIH doesn’t rank it in its absorption comparison, but it is the form used in the largest recent sleep study.
One label tip matters more than the form: look for the elemental magnesium. A capsule can hold a lot of a magnesium compound but much less actual magnesium. The safety limit below is about elemental magnesium.
Which Is Better for Sleep and Calm?
Glycinate. In a 2025 trial of 155 adults with poor sleep, 250 mg a day of magnesium as bisglycinate improved insomnia scores modestly more than a placebo after four weeks. The authors called the benefit modest, and people who got less magnesium from food seemed to gain more.
Citrate hasn’t been tested for sleep in the same way, and because it can loosen stools, it’s a less comfortable choice to take every night. Our magnesium for sleep guide covers the studies, timing and how magnesium compares with melatonin.
Which Is Better for Constipation?
Citrate. MedlinePlus describes magnesium citrate as a saline laxative used short-term for occasional constipation. It works by keeping water in the stool, which softens it and increases bowel movements. Laxative products come as a liquid or a powder to mix, which is different from a daily supplement capsule.
MedlinePlus says to tell your doctor before using it if you have kidney disease or are on a magnesium- or sodium-restricted diet, and to check with a doctor if you have a sudden change in bowel habits lasting more than two weeks. Constipation that keeps coming back is worth a doctor’s visit, not a daily laxative.
What About Magnesium Oxide?
Oxide is the cheapest form and packs a lot of magnesium into each tablet, which is why it’s common in budget supplements. But the NIH says it is absorbed less completely than citrate and similar forms. If you are choosing between glycinate and oxide for sleep or everyday use, glycinate is the better bet.
How Much Is Safe?
- Daily needs: the NIH recommends 310 to 320 mg a day for adult women and 400 to 420 mg for adult men, from food, drinks and supplements together.
- Supplement limit: no more than 350 mg a day of magnesium from supplements for adults, unless a doctor recommends more. Food doesn’t count toward this limit.
- Too much: the NIH says high doses from supplements can cause diarrhea, nausea and stomach cramps.
- Talk to a doctor first if you have kidney disease, are pregnant, or take antibiotics, osteoporosis drugs, diuretics or acid reflux medicine, which can interact with magnesium.
Can You Take Both?
You can, but the total still has to fit under the 350 mg supplement limit, so taking both usually means taking less of each. Most people do fine with one form. If you want help with sleep and constipation at the same time, ask your doctor or pharmacist which combination makes sense for you.
Our Picks
We chose these from the best-reviewed options in each form. All were in stock for US delivery when we checked. Prices change often, so check the current price on each listing, and read the label for the elemental magnesium per serving.
| Pick | Form | Per serving (label) | Best for |
|---|---|---|---|
| Nature Made Magnesium Glycinate | Glycinate (bisglycinate) | 200 mg, 2 capsules | Sleep and everyday use |
| Doctor’s Best High Absorption Magnesium | Glycinate lysinate chelate | 200 mg, 2 tablets (100 mg each) | Adjusting your dose |
| Nature Made Magnesium Citrate | Citrate | 250 mg | Citrate at a moderate dose |
| NOW Magnesium Citrate | Citrate | See label | Vegan capsules |
1. Nature Made Magnesium Glycinate: Best Glycinate
Nature Made Magnesium Glycinate gives 200 mg of magnesium as bisglycinate per two-capsule serving, under the 350 mg supplement limit. It had a 4.6-star average from about 22,500 ratings when we checked, and the bottle holds a 90-day supply.
2. Doctor’s Best High Absorption Magnesium: Best for Adjusting Your Dose
Doctor’s Best High Absorption Magnesium uses a chelated glycinate-lysinate form at 100 mg per tablet, so you can start with one tablet and build up. It had a 4.6-star average from more than 76,000 ratings when we checked.
3. Nature Made Magnesium Citrate: Best Citrate
Nature Made Magnesium Citrate lists 250 mg of magnesium per serving in softgels. It had a 4.7-star average from about 25,300 ratings when we checked. Start low if citrate tends to loosen your stools.
4. NOW Magnesium Citrate: Best Vegan Citrate
NOW Magnesium Citrate comes as vegan capsules in a 240-count bottle, and NOW says its manufacturing process has an A-rated third-party certification. It had a 4.7-star average from about 25,900 ratings when we checked. Check the label for the dose per serving.
Our Verdict
For most people taking magnesium for sleep, calm or general health, glycinate is the better daily choice: it’s the form with the best sleep evidence, and it’s less likely to send you to the bathroom. Choose citrate if you also want help with occasional constipation. Either way, read the label for elemental magnesium and stay at or under 350 mg a day from supplements. Our picks: Nature Made Magnesium Glycinate for glycinate and Nature Made Magnesium Citrate for citrate.
Frequently Asked Questions
Is magnesium glycinate or citrate better?
It depends on your goal. Glycinate is the form used in the best recent sleep trial and is the usual pick for sleep. Citrate is well absorbed but is also sold as a laxative, so it suits people who want help with occasional constipation.
Is magnesium glycinate or citrate better for sleep?
Glycinate. A 2025 trial found that 250 mg a day of magnesium as bisglycinate modestly improved insomnia scores compared with a placebo. Citrate has not been tested the same way, and it is more likely to loosen your stools.
Does magnesium citrate make you poop?
It can. MedlinePlus describes magnesium citrate as a saline laxative used short-term for occasional constipation. It keeps water in the stool, which softens it and increases bowel movements.
What is the difference between magnesium glycinate and bisglycinate?
In practice they are the same thing. Bisglycinate means each magnesium is bound to two glycine molecules, and most glycinate supplements use this form.
How much magnesium can I take a day?
The NIH sets the upper limit for adults at 350 mg a day from supplements, unless a doctor recommends more. Magnesium from food does not count toward that limit.
Is magnesium oxide better than glycinate?
Not for absorption. The NIH says oxide is absorbed less completely than forms like citrate, though it is cheap and packs a lot of magnesium into each tablet.
Sources
- NIH Office of Dietary Supplements: Magnesium fact sheet for health professionals
- NIH Office of Dietary Supplements: Magnesium fact sheet for consumers
- MedlinePlus: Magnesium Citrate
- Schuster et al. (2025), Magnesium bisglycinate supplementation in healthy adults reporting poor sleep, Nature and Science of Sleep
- Product listings for the supplements above, checked October 11, 2026
This article is for general information, not medical advice. If you have a health condition or take medication, talk to your doctor first. Read our Health Disclaimer.
