How Much Magnesium Per Day for Women?
Informational summary of NIH guidance — not medical advice. Talk to a clinician for personalised dosing, especially in pregnancy or with kidney disease.
Adult women need 310mg/day of magnesium (ages 19-30) or 320mg/day (31+), from food and supplements combined, per NIH guidelines. Since most women fall short from diet alone, a 200-400mg elemental magnesium supplement — glycinate is the gentlest, best-absorbed form — is common.
Needs rise to 350-360mg/day in pregnancy. Adult men need more: 400mg/day (19-30) or 420mg/day (31+).
Know your number? See the best magnesium picks at that dose →
Magnesium RDA by Age and Sex
These are the total daily magnesium needs from all sources (food + supplements), set by the National Institutes of Health:
| Age Group | Female | Male | Pregnant | Lactating |
|---|---|---|---|---|
| 1-3 years | 80 mg | 80 mg | — | — |
| 4-8 years | 130 mg | 130 mg | — | — |
| 9-13 years | 240 mg | 240 mg | — | — |
| 14-18 years | 360 mg | 410 mg | 400 mg | 360 mg |
| 19-30 years | 310 mg | 400 mg | 350 mg | 310 mg |
| 31+ years | 320 mg | 420 mg | 360 mg | 320 mg |
Source: NIH Office of Dietary Supplements
Since most women fall short of the RDA from diet alone, a 200-400mg elemental magnesium supplement is common — glycinate is the gentlest, best-absorbed form.
In pregnancy, the RDA rises to 350-360mg/day (400mg for ages 14-18). Supplemental magnesium should stay at or below the 350mg/day upper limit unless your obstetrician advises otherwise.
How Much Magnesium Should Men Take?
The RDA for adult men is 400mg/day (ages 19-30) or 420mg/day (31+), from all sources combined — noticeably higher than the RDA for women shown above.
Diets often fall short of this too. A 200-400mg elemental magnesium supplement is typical for men as well, the same range commonly used for women.
The tolerable upper limit for supplemental magnesium is 350mg/day for adults of either sex. Above that, the most common effect is loose stools, not toxicity, in healthy adults with normal kidney function.
Elemental vs. Compound Weight
Whatever your target number, it only applies to elemental magnesium — the actual magnesium content, not the total weight of the compound on the label (glycinate, citrate, oxide, etc.).
A 2,000mg magnesium glycinate capsule might contain only about 280mg of elemental magnesium.
Check the Supplement Facts panel for the line that says "Magnesium," followed by the compound form in parentheses. That number in front of "mg" is the elemental amount that counts toward your daily target.
A well-absorbed way to hit that range: Vitamin Shoppe Magnesium Glycinate 400mg $0.23/day delivers a full clinical-range dose in two tablets and is gentle on the stomach. Compare every verified pick, including quality- and budget-focused options, in the full best magnesium guide.
Frequently Asked Questions
How much magnesium should women take daily?
310mg/day if you're 19-30, or 320mg/day at 31 and older, from food and supplements combined. Most women fall short from diet alone, so a 200-400mg elemental magnesium supplement — glycinate is the gentlest, best-absorbed form — is a common add-on. Needs go up in pregnancy (350-400mg total) and lactation.
How much magnesium is safe during pregnancy?
350-360mg/day total if you're 19 or older (400mg for ages 14-18). Magnesium is generally considered safe in pregnancy and is sometimes used for leg cramps, but keep supplemental magnesium at or below 350mg/day unless your obstetrician says otherwise. Clear it with your prenatal provider first.
How much magnesium should men take per day?
400mg/day if you're 19-30, 420mg/day at 31 and older — noticeably more than the RDA for women. Diets often fall short here too, so a 200-400mg elemental magnesium supplement is typical, the same range used for women. The supplemental upper limit stays 350mg/day for either sex.
Can you take too much magnesium?
The supplemental upper limit is 350mg/day (NIH). Exceeding this primarily causes diarrhea in healthy adults. Dangerous toxicity requires very high doses or kidney disease. Magnesium glycinate is the least likely form to cause GI side effects.
Related Guides
- Magnesium Dosage Guide — Full NIH RDA table, clinical trial doses by goal, elemental vs compound explained
- Is 500mg of Magnesium Too Much? — Elemental vs compound math for a specific dose
- Best Magnesium Overall — Every verified pick, ranked by cost per effective dose
Sources
- NIH Office of Dietary Supplements. "Magnesium: Fact Sheet for Health Professionals." ods.od.nih.gov
- Firoz M, Graber M. "Bioavailability of US commercial magnesium preparations." Magnes Res. 2001;14(4):257-62. PMID: 11794633