Magnesium Amounts Used in Sleep Studies (2026)
Sleep trials of plain magnesium used 250 to 729 mg of magnesium a day. The newest, a 2025 trial in 155 adults, used 250 mg as glycinate for 4 weeks and found a small benefit. NIH’s limit for magnesium from pills is 350 mg a day, and two of the older trials went over it under supervision. These are amounts studied, not advice.
If you want to try it
- Our pick: Revive MD Magnesium Glycinate: 200 mg of magnesium in 2 capsules, on the Informed Sport list, $0.33 a day at Revive MD’s own price. On the Informed Sport list: every batch is tested for drugs banned in sport. It is not a check of the label. Glycinate is the form the 2025 trial used.Check price
- KAL Magnesium Glycinate 350 mg: 240 capsules, about 88 mg each. One serving (4 capsules, 350 mg) is the whole limit. Not on a testing list.Check price
- BulkSupplements Magnesium Glycinate Powder: 300 mg in ¾ teaspoon (2.2 g), $0.13 per 200 mg at list price. Its label names glycinate and oxide, so it is a blend. On NSF/ANSI 173.Check price
Prices are at brand list prices; prices on Amazon differ; checked October 14, 2026.
What the sleep trials used
| Trial | Amount and form | Who and how long | Result |
|---|---|---|---|
| Schuster 2025 | 250 mg, glycinate | 155 adults with poor sleep, 4 weeks | Small benefit on an insomnia score |
| Nielsen 2010 | 320 mg, citrate | 100 adults over 51, 7 weeks | Sleep scores improved about as much on placebo |
| Abbasi 2012 | 500 mg | 46 older adults with insomnia, 8 weeks | Some sleep measures better; total sleep not clearly |
| Held 2002 | Up to 729 mg, fizzy tablets | 12 adults aged 60 to 80, 20 days | More deep sleep on a brain-wave test |
Pooled, the results were small. A 2021 review pooled the three trials in older adults (151 people): they fell asleep about 17 minutes faster than on placebo, total sleep did not clearly change, and the evidence was rated low to very low quality (Mah 2021).
| Item | Value (mg) |
|---|---|
| 2025 trial, glycinate (155 adults) | 250 mg |
| 2010 trial, citrate (100 adults) | 320 mg |
| NIH limit for pills | 350 mg |
| 2012 trial (46 older adults) | 500 mg |
| 2002 trial (12 older adults) | up to 729 mg |
Above the limit, diarrhea is the usual result. The dosage guide explains the limit, and magnesium and sleep covers each trial.
Which form for sleep
Glycinate (also sold as bisglycinate) is the form the 2025 trial used. No trial shows one form works better for sleep than another. Small studies found the citrate, aspartate, lactate and chloride forms absorbed better than oxide and sulfate (NIH). NIH says nothing about glycinate either way. The glycine in a capsule is small: a 200 mg magnesium serving carries about 1.2 g of glycine, while the glycine sleep trial used 3 g (Bannai 2012).
What labels give
Of the 833 magnesium labels we read in NIH’s label database, the median serving gives 250 mg of magnesium, but the median day as the label directs is 399 mg, because many labels say to take more than one serving. 244 labels name oxide and 94 name glycinate or bisglycinate. A label is counted once for each form of magnesium its Supplement Facts panel names, so a label with two forms counts under both.
- Amount: The “Magnesium” line on the Supplement Facts panel is the magnesium itself (the elemental amount), not the weight of the whole compound (NIH). Multiply by the servings a day the label directs.
- Timing: take it when you will remember; with food if it upsets your stomach (best time to take magnesium).
- Medicines: Antibiotics: take tetracyclines (such as doxycycline) or quinolones (such as ciprofloxacin) at least 2 hours before or 4 to 6 hours after magnesium (NIH).
- Kidneys: If you have kidney disease, ask your doctor before you take magnesium. Weak kidneys cannot clear the extra, so it can build up (NIH).
Frequently asked questions
What amounts have magnesium sleep studies used?
Sleep trials of plain magnesium used 250 to 729 mg of magnesium a day, including a 2025 trial of 250 mg as glycinate (Schuster 2025). Trials of magnesium L-threonate are separate: they used 1 to 2 g of the compound, about 72 to 144 mg of magnesium. These are the amounts studied, not advice. Ask your doctor about any dose.
Which form of magnesium has been studied for sleep?
The 2025 trial used glycinate (bisglycinate). The older trials used citrate, oxide and fizzy tablets; the citrate trial did no better than placebo on sleep scores. Small studies found the citrate, aspartate, lactate and chloride forms absorbed better than oxide and sulfate (NIH). NIH says nothing about glycinate either way.
Is there an official magnesium dose for sleep?
No. The official number is the RDA for intake from food and pills together: 310 to 320 mg a day for women and 400 to 420 mg for men. The limit for pills is 350 mg a day.
What did the studies find?
Small and mixed results. Pooling 3 trials in 151 older adults found people fell asleep about 17 minutes faster than on placebo, with no clear change in total sleep, and the evidence was rated low to very low quality (Mah 2021). The 2025 glycinate trial found a small benefit on an insomnia score (Schuster 2025). See a doctor about sleep problems that last.
Related
- Magnesium and sleep · magnesium dosage guide · best time to take it
- Magnesium glycinate: uses, dose and cost · magnesium guide
Sources
- Schuster J, et al. Magnesium bisglycinate supplementation in healthy adults reporting poor sleep. Nat Sci Sleep. 2025. PubMed 40918053
- Nielsen FH, et al. Magnesium supplementation improves indicators of low magnesium status and inflammatory stress in adults older than 51 years with poor quality sleep. Magnes Res. 2010. PubMed 21199787
- Abbasi B, et al. The effect of magnesium supplementation on primary insomnia in elderly. J Res Med Sci. 2012. PubMed 23853635
- Held K, et al. Oral Mg(2+) supplementation reverses age-related neuroendocrine and sleep EEG changes in humans. Pharmacopsychiatry. 2002. PubMed 12163983
- Mah J, Pitre T. Oral magnesium supplementation for insomnia in older adults. BMC Complement Med Ther. 2021. PubMed 33865376
- Bannai M, Kawai N. New therapeutic strategy for amino acid medicine: glycine improves the quality of sleep. J Pharmacol Sci. 2012. PubMed 22293292
- NIH Office of Dietary Supplements. Magnesium fact sheet for health professionals (updated January 6, 2026).
- NIH Dietary Supplement Label Database (labels read August 29, 2026). Prices: each brand’s own list price, checked October 14, 2026. Download the data (JSON).
This page is for information. It is not medical advice.