Magnesium glycinate vs citrate, and which to take
How magnesium glycinate and citrate differ, what the absorption and sleep studies show, which is easier on the stomach and whether you can take both together.
- Written by
- Ben L.
- Last updated
- Reading time
- 8 min read
Overview
Magnesium glycinate is magnesium joined to glycine, and citrate is magnesium joined to citric acid. Citrate has slightly better absorption data and glycinate has the one positive sleep trial, but no study settles which is better. Both work as daily magnesium, and you can take them together at 400 mg or less a day.
Key points
- 1,000 mg of either form gives only about 120 to 160 mg of actual magnesium, so go by the label's magnesium figure.
- Citrate raised blood magnesium the most in a 60-day trial, but the studies are few and small.
- Glycinate has one recent trial showing a small sleep benefit, and no study has compared the two forms for sleep.
- No study shows that glycinate is gentler on the stomach, and diarrhoea depends mostly on the dose.
- You can take both together if your total from supplements stays at 400 mg or less a day.
What's the difference between magnesium glycinate and citrate?
Start with a number. A 1,000 mg scoop of magnesium glycinate or magnesium citrate gives you only about 120 to 160 mg of actual magnesium. The rest is what the magnesium is joined to, and that's where magnesium glycinate vs citrate really differ.
Glycinate is magnesium joined to glycine, a small amino acid. Citrate is magnesium joined to citric acid, the acid in lemons. Both are "organic" forms, and both are among the most common in UK supplements.
| Glycinate | Citrate | |
|---|---|---|
| Joined to | Glycine, an amino acid | Citric acid |
| Magnesium in 1,000 mg | About 140 mg | About 120 to 160 mg |
| Absorption | No significant rise after one dose in one study [1] | Raised blood magnesium most in a 60-day trial [2] |
| Sleep research | One small trial, small benefit [3] | One trial, no better than a placebo [4] |
| In the bowel | Not studied on its own | Draws water into the bowel [5] |
The magnesium figures are our own sums from each compound's chemical formula [6][7]. Citrate varies more because some citrate ingredients hold water, which adds weight but no magnesium. Either way, go by the magnesium figure on the label, not the weight of the compound. Our guide to how much magnesium per day shows how to read it.
Which is absorbed better, glycinate or citrate?
Citrate has the better evidence, though the studies are few and small. No study has compared the two over weeks in a way that settles it.
In a 60-day trial at the University of Reading, 46 healthy adults took about 300 mg of magnesium a day as citrate, an amino-acid chelate, magnesium oxide or a placebo. Citrate raised blood magnesium the most Early [2]. The paper doesn't say whether its chelate was a glycinate, so it can't speak for glycinate directly.
In a 2024 study, 40 healthy adults took one 375 mg dose of magnesium in each of four forms, a week apart. Blood magnesium rose 4 hours after citrate, but the rise after bisglycinate wasn't significant at any point. When the forms were compared directly, though, the differences weren't significant either Early [1]. The study was funded by the maker of a third, rival form.
In practice, the gap between the two forms is smaller than the gap between taking magnesium every day and forgetting it half the week.
Which is better for sleep, glycinate or citrate?
Glycinate has the only positive trial, but no study has compared the two forms for sleep.
In a 2025 German trial, 155 adults aged 18 to 65 who slept poorly took magnesium bisglycinate giving 250 mg of magnesium, or a placebo, 30 to 60 minutes before bed for 4 weeks. Their insomnia scores fell by 3.9 points, against 2.3 on the placebo, a small benefit Early [3].
In a 2010 US trial, 100 adults aged 51 to 85 who slept poorly took 320 mg of magnesium a day as citrate, or a placebo, for 7 weeks. Sleep scores improved just as much on the placebo Early [4].
The two trials differ in age, dose and length, so they can't show that one form is better for sleep. Our guide to magnesium for sleep covers all the trials.
Which is gentler on the stomach?
Nobody knows for sure, because no study has compared the two for stomach upsets. What's clear is that diarrhoea depends mostly on the dose. The NHS says taking more than 400 mg of magnesium for a short time can cause diarrhoea [8].
Magnesium that isn't absorbed draws water into the bowel, and citrate does this well enough to be used in bowel-cleansing medicines taken before a hospital bowel test. One such medicine's leaflet says magnesium citrate "acts as an osmotic laxative by retaining moisture in the colon" [5]. Each sachet gives about 2.1 g of magnesium, roughly five times the NHS line for supplements.
Glycinate is often described as the gentler form, but we found no study in healthy adults that compares it with citrate. If either form upsets your stomach, try a smaller amount or split it through the day before you switch. Our guide to magnesium side effects covers what helps.
Can you take magnesium citrate and glycinate together?
Yes. They're two forms of the same mineral, so add up the magnesium from both. The NHS says 400 mg or less a day of magnesium from supplements is unlikely to cause any harm [8].
Here's a worked example. A product giving 150 mg of magnesium from glycinate and 100 mg from citrate gives you 250 mg in total. That total, plus any multivitamin, is the number to check against the 400 mg line.
Which should you choose?
The one you'll take every day at a sensible dose. If you want a tie-breaker, these are the honest ones.
- For the most absorption data, citrate, which raised blood magnesium most in the 60-day trial [2].
- For an evening routine, glycinate, which has the one recent positive sleep trial [3].
- If loose stools put you off, either form at a lower dose, split through the day.
- If you can't decide, a product that combines them, keeping the total magnesium to 400 mg or less [8].
Whichever you pick, our complete guide to magnesium glycinate and our guide to magnesium citrate go into each form in more depth.
Where Nooroots fits
If you'd rather not choose, Nooroots Triple Magnesium combines both forms, glycinate (1,150 mg) and citrate (500 mg), with malate (500 mg). Together they give 301 mg of magnesium a day, 80% of the NRV, in three capsules. That's below the NHS's 400 mg line for supplements.
Triple Magnesium's magnesium contributes to a reduction of tiredness and fatigue and to normal psychological function.
Coming soon. Triple Magnesium isn't on sale yet.
Frequently asked questions
Is magnesium bisglycinate the same as glycinate?
Yes. "Bisglycinate" spells out that each magnesium is paired with two glycines, and labels use both names for the same compound. A "buffered" glycinate is different, because it has magnesium oxide added.
What's the difference between magnesium and magnesium glycinate?
Magnesium is the mineral your body needs. Magnesium glycinate is a supplement form in which magnesium is joined to glycine, and only about 14% of its weight is magnesium. The NHS says adults need 300 mg of magnesium a day for men and 270 mg for women [8].
How much magnesium is in magnesium citrate?
About 12% to 16% of its weight for the usual form, depending on how much water the ingredient holds [7]. So 1,000 mg of magnesium citrate gives roughly 120 to 160 mg of magnesium. Check the magnesium figure on the label.
Which magnesium is best for sleep?
No form has been shown to be best. Glycinate has the most recent positive trial, in which 250 mg of magnesium a day for 4 weeks gave a small improvement in sleep scores [3].
Which magnesium is easiest on the stomach?
No study has compared the forms for this, so there's no proven answer. Any form can cause diarrhoea above about 400 mg of magnesium a day from supplements [8].
Which magnesium is best?
No single form is best for everyone. Citrate and glycinate are both well-studied organic forms, and the right one is the one you'll take every day at 400 mg of magnesium or less from supplements [8].
References
Every study here is listed so you can read it yourself. This guide is for general information and doesn't replace advice from your GP or pharmacist. We review it when new research is published.
- Pajuelo D, Meissner JM, Negra T, et al. (2024). Comparative clinical study on magnesium absorption and side effects after oral intake of microencapsulated magnesium (MAGSHAPE microcapsules) versus other magnesium sources. Nutrients 16(24): 4367. PMID 39770988
- Walker AF, Marakis G, Christie S, et al. (2003). Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnesium Research 16(3): 183–191. PMID 14596323
- Schuster J, Cycelskij I, Lopresti A, et al. (2025). Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nature and Science of Sleep 17: 2027–2040. PMID 40918053
- Nielsen FH, Johnson LK, Zeng H (2010). Magnesium supplementation improves indicators of low magnesium status and inflammatory stress in adults older than 51 years with poor quality sleep. Magnesium Research 23(4): 158–168. PMID 21199787
- Ferring Pharmaceuticals Ltd. PICOLAX powder for oral solution: Summary of Product Characteristics (sections 2, 4.1, 4.2, 5.1 and 5.2). Electronic medicines compendium, updated 16 June 2025. Accessed 18 October 2026. medicines.org.uk/emc/product/915/smpc
- PubChem. Magnesium glycinate (CID 84645). Accessed 18 October 2026. pubchem.ncbi.nlm.nih.gov/compound/84645
- PubChem. Trimagnesium dicitrate (CID 6099959). Accessed 18 October 2026. pubchem.ncbi.nlm.nih.gov/compound/6099959
- NHS. Vitamins and minerals: others (magnesium section). Accessed 18 October 2026. nhs.uk/conditions/vitamins-and-minerals/others
