Ghost Fitness/Magnesium/Is 400mg of elemental magnesium too much?
Is 400mg of elemental magnesium too much?
The short answer
No: 400mg of elemental magnesium from a supplement sits at the UK guidance level exactly, the top of the range rather than over it, with the laxative effect the practical ceiling. The level is supplemental, food does not count toward it, so 300mg of elemental magnesium on top of a diet that supplies 250mg is a 550mg total and fine.
- 400mg elemental from a supplementat the guidance level of about 400mg supplemental a day: the top, not over
- The teachthe level is supplemental: food magnesium does not count toward it
- 300mg on top of fooda 250mg diet plus 300mg supplemental is a 550mg total and fine
- Whythe guidance was set for supplements on top of a normal diet; food's magnesium is absorbed at a lower fraction and sits inside the assumption
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 on top of food, inside the level: 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 three ceilings are on the maximum dose page; the elemental unit on the elemental page.
400mg elemental from a supplement, placed exactly, and the ceiling that arrives before it for many
Is 400mg of elemental magnesium too much is answered by placing the figure exactly: the UK expert group's guidance level for supplemental magnesium is about 400mg a day, an amount from supplements on top of food not expected to cause adverse effects in healthy adults, so 400mg of elemental magnesium from a supplement sits at the level rather than over it, the top of the range, not too much in the guidance sense and not dangerous in working kidneys, the too-much pages' rungs beginning above it. Two things arrive before the level for many people. The laxative effect: the osmotic loose stools of a dose that exceeds absorption, which for citrate and oxide often arrives below 400mg and for bisglycinate often arrives above it, the salt deciding whether 400mg elemental is a comfortable dose or a bathroom morning, so that 400mg as glycinate, the variant asks, is a full dose in the best-tolerated salt and usually fine, and 400mg as oxide is the same magnesium with most of it left in the gut. The EU's stricter figure: EFSA's 250mg upper level set at the laxative threshold rather than at harm, which a reader who prefers to sit under splits or halves toward, the maximum-dose page's three ceilings. And the honest note about benefit: nothing accrues over 300mg for a lifter whose shortfall 300mg closes, the deficiency pattern meaning that the fourth hundred milligrams is excreted rather than used, so 400mg elemental is fine, is the ceiling, and is a hundred milligrams more than the section's dose for no gain.
The teach the variant asks for, supplemental versus total, and why 300mg on top of food is fine
The variant asking whether 300mg of elemental magnesium a day is too much on top of food is asking the most useful question on the page, and the answer is a distinction most readers have never been told: the guidance level is supplemental, and food does not count toward it. The expert group set its 400mg figure for magnesium taken as supplements in addition to a normal diet, the diet's magnesium being assumed and not summed, for two reasons: food magnesium is absorbed at a lower fraction than a supplement's, bound in fibre, phytate and food matrices and released slowly across a meal, so that its osmotic load is small, and the reference intakes for food, 300mg for men and 270mg for women, are already inside the population the guidance was set for. So a reader whose diet supplies 250mg of magnesium a day and who takes 300mg elemental from a supplement has a total intake of 550mg, and that total is not compared against the 400mg level, the supplement's 300mg being what is compared and sitting comfortably under it, the food's 250mg being what the reference intake wanted anyway. The same reader taking 400mg from a supplement on top of the same diet is at the level, and taking 500mg is over it, the food unchanged throughout. The one case where food is counted is the tolerable upper level of the EU, which includes water and added magnesium in fortified foods, still excluding ordinary food magnesium. The question filed: 400mg of elemental magnesium from a supplement is at the guidance level and not over it, fine in working kidneys with the salt deciding the gut and nothing gained over 300mg, and 300mg on top of food is fine because the level is supplemental and food does not count toward it, the worked example being 300mg elemental on top of whatever the plate supplies, inside the level by a hundred milligrams, 1500mg bisglycinate at 80% NRV, £19.99 for 90 days at 22p.
| The figure | Where it sits | The note |
|---|---|---|
| 400mg elemental from a supplement | At the 400mg guidance level: the top, not over | Fine in working kidneys; the salt decides the gut |
| 400mg as glycinate | A full dose in the best-tolerated salt | Usually comfortable; nothing gained over 300 |
| 400mg as oxide | The same magnesium, most left in the gut | The laxative effect arrives below the level |
| 300mg on top of a 250mg diet | A 550mg total; 300mg compared with the level | Fine: food does not count toward the supplemental level |
| Why food is excluded | Lower absorption fraction; already inside the reference intake | The guidance assumed a normal diet |
| The EU figure | 250mg including water and fortification, excluding ordinary food | Split or halve toward it if preferred |
The verdict, at the level, and food outside it
Is 400mg of elemental magnesium too much: no, 400mg from a supplement sitting at the UK guidance level of about 400mg supplemental exactly, the top of the range rather than over it, fine in working kidneys with the salt deciding whether the laxative effect arrives first and nothing gained over 300mg, and the teach the variant asks for being that the level is supplemental and food does not count toward it, so 300mg of elemental magnesium on top of a diet supplying 250mg is a 550mg total that is compared with the level only by its supplemental 300mg and is fine. Inside the level by a hundred milligrams: 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
- Place 400mg elemental at the level: the top, not over.
- Let the salt decide the gut: glycinate comfortable, oxide not.
- Compare only the supplement with the level: food does not count.
- Read 300mg on top of food as fine: the guidance assumed the diet.
- Expect nothing from the fourth hundred: 300mg closes the shortfall.
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
Is 400mg of elemental magnesium glycinate too much?
No: 400mg elemental from a supplement sits at the UK guidance level of about 400mg supplemental exactly, and as bisglycinate, the best-tolerated salt, it is usually comfortable, though nothing accrues over 300mg for a lifter whose shortfall 300mg closes.
Does the magnesium in my food count toward the 400mg limit?
No: the guidance level is for supplements on top of a normal diet, food magnesium being absorbed at a lower fraction and already assumed by the reference intakes, so 300mg supplemental on a 250mg diet is a 550mg total that the guidance compares only by its 300mg.
Is 300mg of elemental magnesium a day too much on top of food?
No: 300mg supplemental sits under the 400mg level with room, and the food's magnesium does not count toward it, the total of 550mg or so being what the guidance expected of a normal diet plus a supplement.
Why is the guidance level for supplements only?
Because food magnesium is bound in fibre, phytate and food matrices and released slowly across a meal with a small osmotic load, and because the reference intakes for food were already inside the population the guidance was set for.
Does any limit include food magnesium?
The EU's 250mg tolerable upper level includes water and fortified-food magnesium but still excludes ordinary food, and a reader who prefers to sit under it splits or halves a supplemental dose.
Sources
- 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 European Food Safety Authority's tolerable upper intake level for magnesium: 250mg a day from supplements, water and added sources, set at the threshold of the mild osmotic laxative effect rather than at a level of harm, and distinct from the UK expert group's guidance level of about 400mg. https://www.efsa.europa.eu/en/efsajournal/pub/4186
- 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).
- The magnesium absorption literature: fractional absorption of magnesium falls as the dose rises, so the same daily amount taken in divided doses is absorbed at a higher fraction and with less osmotic laxative effect than a single large dose. PubMed record