Ghost Fitness/Magnesium/How much elemental magnesium per day for a woman?
How much elemental magnesium per day for a woman?
The short answer
270mg a day from all sources is the UK reference nutrient intake for adult women, 320mg when breastfeeding, against a 375mg labelling NRV and a 400mg supplemental ceiling. A 300mg elemental supplement covers a shortfall; elemental, not compound, is the figure to read.
- The RNI270mg a day for adult women, all sources; 320mg when breastfeeding
- The NRV375mg on every label, the same for women and men
- The ceilingabout 400mg supplemental a day, the UK guidance level
- The elemental trap300mg of bisglycinate is about 60mg of magnesium; read the %NRV
Our brand: the worked example on this page
Futuro Labs Magnesium Glycinate
- 22p a day
- 180 capsules, 2 capsules daily
- Lab tested
- Made in the UK
300mg elemental, stated with its maths: Futuro Labs Magnesium Glycinate on Amazon UK, 1500mg bisglycinate giving 300mg elemental at 80% NRV, £19.99 for 90 days at 22p. Full label breakdown. The woman's dose page is here; the over-50 page on the over-50 page.
The three reference points for a woman, and the life stages that move one of them
How much elemental magnesium per day for a woman is read against three reference points, and the word elemental in the question is the one that matters most, so it comes last. Reference point one, the reference nutrient intake: the UK's scientific figure for total magnesium from all sources, food included, is 270mg a day for adult women, the amount judged sufficient for nearly all women in the group, against 300mg for adult men, the small difference reflecting body size, and it is the reference that moves with life stage, breastfeeding raising it to 320mg a day to cover the magnesium in milk, pregnancy carrying no increment in the UK figures but being the stage at which a woman asks her midwife before supplementing, and the menopause changing the bone-health context rather than the magnesium figure, the over-50 page's subject. Reference point two, the labelling NRV: 375mg on every UK label, the same for women and men, a convention for the %NRV column and not a target, so that a woman's 300mg elemental supplement reads 80% NRV on the tub and exceeds her 270mg RNI, which is fine, the RNI being total intake and the diet supplying its own share. Reference point three, the ceiling: the UK expert group's supplemental guidance level of about 400mg a day, the same for women and men, under which 300mg elemental sits with room and above which the laxative effect and the guidance both say no, the 400mg-woman page's finding that a full 400mg is the ceiling and not a target. A woman whose diet audit finds magnesium short, greens, nuts, seeds, legumes and wholegrains being the audit's items, covers the shortfall with 300mg elemental and lands, with diet, near or above her RNI; a woman whose diet is replete needs less or none.
The elemental trap that halves a dose on paper, the female-lifter note, and the dose filed
The elemental trap is why the question says elemental and why the answer must too: labels declare magnesium two ways, as the mineral itself, elemental, or as the weight of the compound carrying it, and a woman reading 300mg magnesium glycinate on a front label may be reading 300mg of elemental magnesium at 80% NRV over two or three capsules or 300mg of bisglycinate compound carrying about 60mg of magnesium at 16% NRV in one capsule, a fifth of the dose, the 300mg-of-what teach with the %NRV line as the settlement, so a woman targeting her 270mg RNI reads the %NRV, 80% meaning the dose she meant and 16% meaning five capsules or another tub. The female-lifter note: training raises magnesium needs modestly through sweat, tens of milligrams a session, and a training diet built on protein and light on greens, nuts and wholegrains is the common shortfall pattern in either sex, so the diet audit decides and the dose is the same 300mg elemental as a man's, a woman's smaller RNI meaning the supplement covers her shortfall with more margin rather than that she takes less, the split across breakfast and dinner suiting a smaller frame's tolerance. The dose filed: 270mg a day from all sources for an adult woman, 320mg when breastfeeding, read against a 375mg NRV that is the same for everyone and a 400mg supplemental ceiling that is too, with a 300mg elemental supplement, read as elemental by its 80% NRV, covering any shortfall a diet audit finds, the worked example printing 1500mg bisglycinate giving 300mg elemental at 80% NRV so that the trap cannot be sprung, £19.99 for 90 days at 22p, and this site giving no supplement guidance to anyone under eighteen and sending pregnancy to the midwife.
| The reference point | The figure | What it means for a supplement |
|---|---|---|
| The RNI, adult women | 270mg a day, all sources | A 300mg elemental supplement exceeds it alone; diet adds its share |
| The RNI, breastfeeding | 320mg a day | The one life stage that moves the figure |
| Pregnancy | No increment in UK figures | Ask the midwife before supplementing |
| The NRV | 375mg, the same for everyone | 300mg reads 80%; a convention, not a target |
| The ceiling | About 400mg supplemental | The same for women and men; the laxative effect first |
| The elemental trapOurs | 300mg compound is about 60mg magnesium, 16% NRV | Read the %NRV; the worked example prints both |
The verdict, 270 by reference and 300 by supplement
How much elemental magnesium per day for a woman: 270mg a day from all sources by the UK reference nutrient intake, 320mg when breastfeeding, against a 375mg labelling NRV and a 400mg supplemental ceiling that are the same for everyone, with a 300mg elemental supplement covering any shortfall a diet audit finds and the word elemental read off the %NRV so that a compound weight does not halve the dose on paper, pregnancy going to the midwife and under-eighteens outside this site's guidance. The dose printed with its maths: Futuro Labs Magnesium Glycinate, 1500mg bisglycinate giving 300mg elemental at 80% NRV, £19.99 for 90 days at 22p a day.
What to check on the label
- Know the RNI: 270mg a day, 320mg breastfeeding, all sources.
- Read the NRV as a convention: 375mg for everyone; 300mg is 80%.
- Respect the ceiling: 400mg supplemental, the same for all.
- Read elemental off the %NRV: 80%, not 16%.
- Ask the midwife in pregnancy: and take no dose from this site under eighteen.
Our brand
The worked example: Futuro Labs Magnesium Glycinate
Futuro Labs Magnesium Glycinate is the worked example for magnesium reviews because its label states every number a review needs: 1500mg magnesium bisglycinate at 20%, 300mg elemental, 80% NRV, 2 capsules a day, 180 capsules for £19.99, 22p a day, UK made, vegan HPMC shell, batch tested for lead, mercury, arsenic and cadmium, and only the register's own magnesium claims printed.
- Elemental magnesium per serving
- 300mg (80% NRV)
- Form
- magnesium bisglycinate 20%
- Serving
- 2 capsules a day
- Bottle
- 180 capsules, 90 days
- Price
- £19.99 (22p a day)
- Capsule
- vegetarian shell, vegan product
Questions people also ask
What is the recommended magnesium intake for women in the UK?
270mg a day from all sources for adult women, the reference nutrient intake, rising to 320mg when breastfeeding, against 300mg for adult men, with pregnancy carrying no increment in the UK figures and being the stage to ask a midwife first.
Is 300mg of magnesium too much for a woman?
No: 300mg elemental exceeds the 270mg RNI on its own but sits under the 400mg supplemental ceiling, and a diet audit decides whether a shortfall exists to fill; the laxative effect is the practical limit before any harm.
Why does the label say 375mg when women need 270mg?
The 375mg is the labelling nutrient reference value, a convention used for the %NRV column that is the same for women and men, not a target; a woman's scientific reference is the 270mg RNI.
How do I know if my magnesium glycinate dose is really 300mg?
Read the %NRV: 300mg elemental reads about 80%, while 300mg of bisglycinate compound is about 60mg of magnesium and reads about 16%, a fifth of the dose the front implied.
Do women who train need more magnesium?
Modestly: sweat losses are tens of milligrams a session and a protein-heavy training diet light on greens, nuts and wholegrains is the common shortfall, so the diet audit decides and 300mg elemental covers a shortfall with margin.
Sources
- Department of Health. Dietary Reference Values for Food Energy and Nutrients for the United Kingdom. Report on Health and Social Subjects 41, 1991 (magnesium RNI 300mg men, 270mg women).
- Retained Regulation (EU) No 1169/2011, Annex XIII: nutrient reference value for magnesium 375mg. https://www.legislation.gov.uk/eur/2011/1169/annex/XIII
- Expert Group on Vitamins and Minerals. Safe Upper Levels for Vitamins and Minerals. Food Standards Agency, 2003 (magnesium guidance level 400mg a day from supplements). https://cot.food.gov.uk/sites/default/files/vitmin2003.pdf
- The GB claims register, magnesium entries: magnesium contributes to a reduction of tiredness and fatigue, normal psychological function, normal nervous system function, normal muscle function and electrolyte balance, among others. https://www.gov.uk/government/publications/great-britain-nutrition-and-health-claims-nhc-register