Magnesium glycinate vs Magnesium citrate
Which is better for sleep?
Short answer
For sleep, pick glycinate, but expect little: both are rated Limited, and glycinate's one trial found a small drop in insomnia scores after four weeks, while in citrate's one trial sleep improved just as much on placebo.
For constipation, pick citrate: it is sold over the counter as a saline laxative that generally works within half an hour to 6 hours, though a laxative dose holds about 1.9 to 2.9 g of magnesium, far above supplement limits. We found no independent study comparing how well the two are absorbed.
The one form with a positive sleep trial: a small drop in insomnia scores after 4 weeks at 250 mg
An over-the-counter laxative that works in hours; its one sleep trial did no better than placebo
Side by side
| Attribute | Magnesium glycinate | Magnesium citrate |
|---|---|---|
| Evidence for sleep | Limited (poor sleep / insomnia symptoms) | Limited (poor sleep / insomnia symptoms) |
| Best for | Poor sleep | Migraine prevention |
| How fast | 4+ weeks | 4+ weeks |
| Typical form | Bisglycinate, 250 mg elemental Mg | Magnesium dicitrate, 600 mg Mg daily |
| Main caution | Loose stools above about 250–350 mg supplemental Mg | Kidney disease: magnesium can build up, ask first |
| Sold as a laxative? | No; loose stools are a side effect at higher doses | Yes: OTC saline laxative, works in 0.5 to 6 hours |
| Dose in trials (elemental Mg) | 250 mg a day (sleep) | 320 mg (sleep); 600 mg (migraine) |
| Absorption evidence | No independent study found | Beat oxide in one 1990 study; none vs glycinate |
Which should you pick?
Choose Magnesium glycinate if
- you want magnesium for sleep and prefer the form with a small positive trial
- you want a daily supplement at the 250 mg elemental dose the glycinate trial used
- you can give it about 4 weeks before judging whether it helps
Choose Magnesium citrate if
- you need a short-term laxative for occasional constipation and have healthy kidneys
- you want magnesium for migraine prevention, where citrate is rated Moderate at 600 mg a day
- you want a form shown to be better absorbed than magnesium oxide
Questions people ask
Can I take magnesium glycinate and magnesium citrate together?
No interaction between the two is recorded, and neither entry tests them together.
Both count towards the same supplemental magnesium total (EU upper limit 250 mg a day, set to avoid diarrhoea), and a laxative dose of citrate alone holds about 1.9 to 2.9 g, so taking both raises the chance of loose stools; ask a doctor first if you have kidney disease.
Is magnesium glycinate or citrate better for sleep?
Glycinate, narrowly. In its one placebo-controlled trial, 250 mg of magnesium as bisglycinate lowered insomnia scores by 3.9 points against 2.3 on placebo after four weeks, a small effect. In the one citrate trial, 320 mg of magnesium a day improved sleep scores no more than placebo did.
Is magnesium glycinate or citrate better absorbed?
Nobody has shown either is better than the other: we found no independent study comparing the two. Citrate dissolved better and raised urine magnesium more than magnesium oxide in one 1990 study, and claims that glycinate is better absorbed are common in marketing but we found no reliable independent study behind them.
Which is gentler on the stomach, and how much should I take?
No source we found compared their gut side effects; both upper limits (EU 250 mg, US 350 mg of supplemental magnesium a day) are set to avoid diarrhoea, and citrate is the form sold as a laxative.
Check the elemental magnesium on the label, not the compound weight: the trials used 250 mg (glycinate) and 320 mg (citrate) of elemental magnesium for sleep, while one laxative solution lists 1.745 g of magnesium citrate but 290 mg of magnesium per fl oz.
Sources (6)
- Randomised controlled trial Schuster J, Cycelskij I, Lopresti AL, Hahn A. Magnesium Bisglycinate Supplementation in Healthy Adults Reporting Poor Sleep: A Randomized, Placebo-Controlled Trial. Nature and Science of Sleep. 2025.
- Randomised controlled trial Nielsen FH, Johnson LK, Zeng H. Magnesium supplementation improves indicators of low magnesium status and inflammatory stress in adults older than 51 years with poor quality sleep. Magnes Res. 2010.
- Regulator label DailyMed. Magnesium Citrate (magnesium citrate) oral solution, Geri-Care Pharmaceuticals Corp: OTC drug label. Updated June 2026.
- Bioavailability study Lindberg JS, Zobitz MM, Poindexter JR, Pak CY. Magnesium bioavailability from magnesium citrate and magnesium oxide. J Am Coll Nutr. 1990.
- Regulator opinion Scientific Committee on Food, European Commission. Opinion of the Scientific Committee on Food on the Tolerable Upper Intake Level of Magnesium. 2001.
- Randomised controlled trial Peikert A, Wilimzig C, Köhne-Volland R. Prophylaxis of migraine with oral magnesium: results from a prospective, multi-center, placebo-controlled and double-blind randomized study. Cephalalgia. 1996.
Reader notes
Experiences and questions from readers, read by an editor before they appear. They are personal accounts, not evidence, and are not medical advice.