VoltraMagnesium: how much you need, which form, and does it help sleep?
Adults need 310 to 420 mg of magnesium a day from food and drink [1]; EFSA sets 350 mg for men and 300 mg for women [2]. From supplements, the upper limit is 350 mg a day in the US [1] and 250 mg in Europe [3]; magnesium in food doesn't count toward either [1][3].
For sleep, the evidence is weak: a 2026 review of trials concluded it doesn't support magnesium as a routine treatment for insomnia [5].
How much
| What | Amount |
|---|---|
| Adults, from all food and drink (US) | 310 to 420 mg a day [1] |
| Adults (Europe) | 350 mg men, 300 mg women [2] |
| Upper limit from supplements and medicines (US) | 350 mg a day [1] |
| Upper limit from supplements (Europe) | 250 mg a day [3] |
Which form
- Small studies found magnesium aspartate, citrate, lactate and chloride are absorbed more completely than magnesium oxide and sulfate [1].
- The forms most often reported to cause diarrhoea are magnesium carbonate, chloride, gluconate and oxide [1].
- Magnesium glycinate (bisglycinate) is the form sold for sleep. We found no trial comparing it with other forms for sleep.
- Claims that glycinate is better absorbed or easier on the stomach rest on little. In 12 patients who had part of the small intestine removed, absorption was about the same as magnesium oxide (23.5% against 22.8%), though glycinate was better tolerated [8]. In a 2024 study funded by the maker of a competing magnesium product, blood magnesium didn't rise significantly after bisglycinate [9].
Does it help sleep?
- Older adults: three trials with 151 people found they fell asleep about 17 minutes faster, but all the trials were at moderate-to-high risk of bias and the evidence was of low to very low quality [4].
- Adults: a 2026 review of 12 trials found it may give modest benefits for some people, but the findings were inconsistent and it doesn't support magnesium as a routine treatment for insomnia [5].
- Magnesium bisglycinate, 250 mg a day for 4 weeks in adults who slept poorly, gave a small, modest benefit [6]. One of its authors, who also led the 2026 review, runs a research company funded by supplement makers [6]. The product also supplied 1,523 mg of glycine a day, so the benefit can't be pinned on magnesium alone [6].
Safety
Too much magnesium from supplements most often shows up as diarrhoea [1]. A dangerously high blood level usually only happens when people with kidney failure take magnesium salts or medicines that contain magnesium, such as some antacids or laxatives [7], so if you have kidney disease, ask your doctor first.
In Voltra
Log magnesium, like any supplement, on the Eat tab, or tell the Coach to log it.
Frequently asked
How much magnesium do I need a day?
Adults need 310 to 420 mg a day from food and drink. From supplements, don't go above 350 mg a day (250 mg in Europe).
Does magnesium help you sleep?
The evidence is weak and inconsistent: a 2026 review doesn't support it as a routine treatment for insomnia, though some people may get a small benefit.
Which magnesium is best absorbed?
Small studies found aspartate, citrate, lactate and chloride are absorbed better than oxide and sulfate.
Can magnesium cause diarrhoea?
Yes. It's the most common sign of too much from supplements, especially with the carbonate, chloride, gluconate and oxide forms.
Sources
- NIH Office of Dietary Supplements (2026). Magnesium: fact sheet for health professionals (updated 6 January 2026). Recommended intakes, dietary supplements, health risks from excess.
- EFSA Panel on Dietetic Products, Nutrition and Allergies (2015). Scientific Opinion on Dietary Reference Values for magnesium. EFSA Journal 13(7):4186. Abstract.
- European Food Safety Authority (2025). Overview on Tolerable Upper Intake Levels as derived by the SCF and the EFSA NDA Panel (version 11). p. 2, Table 1 and footnote (g).
- Mah J, Pitre T (2021). Oral magnesium supplementation for insomnia in older adults: a systematic review and meta-analysis. BMC Complement Med Ther 21:125. Abstract.
- Lopresti AL, Smith SJ, Drummond PD (2026). Magnesium supplementation for sleep in adults: a systematic review of randomized controlled trials. J Diet Suppl 23(5):553–581. Abstract. 12 trials in the main synthesis.
- Schuster J, Cycelskij I, Lopresti A, Hahn A (2025). Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nat Sci Sleep 17:2027–2040. Abstract and disclosures. 155 adults, 4 weeks.
- دليل MSD الإرشادي، إصدار المستخدم. فرطُ مغنيزيوم الدَّم. In Arabic.
- Schuette SA, Lashner BA, Janghorbani M (1994). Bioavailability of magnesium diglycinate vs magnesium oxide in patients with ileal resection. JPEN J Parenter Enteral Nutr 18(5):430–435. Abstract. 12 patients.
- Pajuelo D, Meissner JM, Negra T, Connolly A, Mullor JL (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. Abstract and conflict-of-interest statement. Funded by Lubrizol Life Science.
Sources checked on 30 September 2026.
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