Updated 26 October 2026. HealthyHey makes magnesium supplements. Every figure below is linked to its source.
For Indian adults, 440 mg a day for men and 370 mg for women, counting magnesium from food and supplements together (ICMR-NIN 2020). The US figures are a little lower: 400 to 420 mg for men and 310 to 320 mg for women (MedlinePlus).
From supplements alone, adults should stay within 350 mg a day unless a doctor advises more (IOM 1997). Most supplements give 100 to 300 mg of elemental magnesium a day.
India's RDA for magnesium
| Group | Magnesium per day |
|---|---|
| Adult men | 440 mg |
| Adult women | 370 mg |
These are the ICMR-NIN 2020 figures. In 2021 FSSAI moved the label reference values to match them, raising magnesium from 385 to 440 mg for men and from 325 to 370 mg for women (FSSAI 2021). They cover all magnesium you take in, from dal, whole grains, nuts, leafy vegetables and water as well as supplements.
US RDA by age
| Age | Male | Female |
|---|---|---|
| 1 to 3 years | 80 mg | 80 mg |
| 4 to 8 years | 130 mg | 130 mg |
| 9 to 13 years | 240 mg | 240 mg |
| 14 to 18 years | 410 mg | 360 mg |
| 19 to 30 years | 400 mg | 310 mg |
| 31 years and older | 420 mg | 320 mg |
| Pregnancy | – | 350 to 400 mg |
| Breastfeeding | – | 310 to 360 mg |
Recommended dietary allowances from the US National Academies, as listed by MedlinePlus (MedlinePlus). Pregnancy and breastfeeding figures vary by age.
The 350 mg limit is for supplements, not food
The tolerable upper intake level for adults and children over 8 is 350 mg of supplementary magnesium a day. It applies only to magnesium from supplements, antacids and medicines. Magnesium in food has not been shown to cause harm, so it does not count toward the limit (IOM 1997).
The limit was set because too much supplemental magnesium loosens stools, which is the first sign of taking more than the gut can handle (IOM 1997). People with kidney disease clear magnesium less well and should take supplements only on medical advice.
How much should you take as a supplement?
A supplement is meant to close the gap between what you eat and the RDA, not to supply the whole amount. Common supplemental amounts are 100 to 300 mg of elemental magnesium a day. For reference, a 2025 sleep trial used 250 mg a day (Schuster 2025) and a 60-day absorption trial used 300 mg a day (Walker 2003).
Split larger amounts. In one study, the share of magnesium absorbed fell from 65% at the lowest intake to 11% at the highest (Fine 1991), so two smaller doses absorb a greater share than one large dose.
Elemental magnesium vs the compound on the label
A label's big number is usually the whole compound, such as "magnesium glycinate 550 mg". Your dose is the elemental magnesium inside it, which depends on the form:
| Form | Magnesium by weight | Compound needed for 100 mg of magnesium |
|---|---|---|
| Magnesium oxide | 60.3% | 166 mg |
| Magnesium citrate (anhydrous) | 16.2% | 617 mg |
| Magnesium bisglycinate (glycinate) | 14.1% | 709 mg |
| Magnesium taurate | 8.9% | 1,124 mg |
| Magnesium L-threonate | 8.3% | 1,205 mg |
So 550 mg of unblended magnesium bisglycinate gives about 78 mg of magnesium. Our magnesium label calculator checks any label, and what percentage of magnesium glycinate is elemental magnesium explains the chemistry.
HealthyHey magnesium glycinate, per serving
- Magnesium Glycinate 22%: 550 mg magnesium glycinate providing 121 mg elemental magnesium in one vegetarian capsule, as printed on the label.
- Magnesium Glycinate 14% Fully Chelated: 121 mg elemental magnesium across two vegetarian capsules, from bisglycinate only.
Either gives a quarter to a third of India's RDA from one serving, leaving room for magnesium from food. Every production batch is tested at an NABL-accredited lab, and our published reports are on the magnesium glycinate report page.
Frequently asked questions
How much elemental magnesium should I take per day?
India's RDA is 440 mg a day for men and 370 mg for women from food and supplements together. Most supplements give 100 to 300 mg of elemental magnesium; keep the supplement part within 350 mg a day unless your doctor advises more.
Is 400 mg of magnesium a day too much?
From food and supplements together, 400 mg is not too much: it is close to India's RDA (440 mg for men, 370 mg for women), which is a target, not a ceiling. From supplements alone, 400 mg is above the 350 mg upper limit for adults, so take that much only on your doctor's advice.
Does magnesium from food count toward the upper limit?
No. The 350 mg upper limit covers magnesium from supplements and medicines only. Magnesium in food has not been shown to cause harm.
How much elemental magnesium is in 500 mg of magnesium glycinate?
At most about 70 mg, because unblended magnesium bisglycinate is 14.1% magnesium by weight. Grades that hold water give less. A label claiming much more is using a second magnesium source as well. The full calculation.
Should I split my magnesium dose?
For larger amounts, yes. The share of magnesium the gut absorbs falls as the amount in one go rises, so two smaller doses absorb a greater share than one large dose.
Who should not take magnesium supplements without advice?
People with kidney disease, because the kidneys remove excess magnesium. Also ask your doctor if you take any regular medicine, especially antibiotics or diuretics, or if you are pregnant or breastfeeding.
Research Sources
- ICMR-National Institute of Nutrition. Nutrient Requirements for Indians: Recommended Dietary Allowances and Estimated Average Requirements, 2020.
- FoodNavigator-Asia. India's RDA levels: regulator again revises vitamin and mineral rules with increase in magnesium, biotin. 11 August 2021. link
- Institute of Medicine. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. National Academies Press, 1997. Chapter 6, Magnesium. link
- MedlinePlus. Magnesium in diet. US National Library of Medicine. link
- Fine KD et al. Intestinal absorption of magnesium from food and supplements. J Clin Invest. 1991;88(2):396-402. doi:10.1172/JCI115317
- Walker AF et al. Mg citrate found more bioavailable than other Mg preparations in a randomised, double-blind study. Magnes Res. 2003;16(3):183-191. PubMed
- Schuster J et al. Magnesium bisglycinate supplementation in healthy adults reporting poor sleep: a randomized, placebo-controlled trial. Nat Sci Sleep. 2025;17:2027-2040. doi:10.2147/NSS.S524348
Related reading: magnesium glycinate vs citrate, how much elemental magnesium is in 500 mg of magnesium glycinate.
This article is educational and is not medical advice. Magnesium supplements are not intended to diagnose, treat, cure or prevent any disease. Consult a qualified healthcare professional before starting any supplement, particularly if you are pregnant, breastfeeding, have kidney disease, or take prescription medicines. Percentages are calculated from standard atomic weights; commercial lots vary with moisture content.