Magnesium
Citrate, bisglycinate, oxide, malate: how the forms of magnesium differ, why the label carries two different numbers and how to choose the right one.
- Magnesium contributes to the reduction of tiredness and fatigue.
- Magnesium contributes to electrolyte balance.
- Magnesium contributes to normal energy-yielding metabolism.
- Magnesium contributes to the normal functioning of the nervous system.
- Magnesium contributes to normal muscle function.
- Magnesium contributes to normal protein synthesis.
- Magnesium contributes to normal psychological function.
- Magnesium contributes to the maintenance of normal bones.
- Magnesium contributes to the maintenance of normal teeth.
- Magnesium has a role in the process of cell division.
The claims apply to a product whose daily dose provides at least 15 % of the reference intake (375 mg).
A varied and balanced diet and a healthy lifestyle are important.
What it is
Magnesium is a mineral the body cannot make and gets from food. There is plenty in nuts, seeds, wholegrains, pulses, dark leafy greens and cocoa. The EU labelling reference intake for adults is 375 mg a day.
Magnesium has a long list of authorised claims in the European Union — they are listed above. They apply to products whose daily dose provides at least 15 % of the reference intake, that is at least 56 mg of magnesium.
Two numbers on the label
In supplements magnesium is always bound to something else — citric acid, glycine, oxide. That is why packs often show two numbers: the weight of the compound (say 2000 mg of magnesium citrate) and the amount of magnesium itself, "elemental" magnesium (say 300 mg). Compare products by the second number.
On our site the dose filter and the claims always work from elemental magnesium.
The forms of magnesium compared
- Magnesium oxide
- about 60 % elemental magnesium — the most of any form, so the tablet is small. Dissolves poorly in water. The cheapest form; at high doses it loosens the stool more often than others.
- Magnesium citrate
- about 15–16 % magnesium, dissolves well, inexpensive. Found in powders and effervescent tablets.
- Magnesium bisglycinate (glycinate)
- about 14 % magnesium, bound to the amino acid glycine. Usually gentle on the stomach, so people who find other forms uncomfortable often choose it. Larger, pricier capsules.
- Magnesium malate
- about 15 % magnesium, bound to malic acid. Close to citrate in its properties.
- Magnesium taurate
- about 9 % magnesium, bound to taurine. More capsules are needed for a given dose.
- Magnesium L-threonate
- about 7–8 % magnesium — the least of any form, so a meaningful dose takes several large capsules; the most expensive form.
Lactate, aspartate, pidolate and carbonate are rarer, usually in complexes. Magnesium chloride is also sold as "magnesium oil" for the skin, and sulphate as bath salts; these are products for another purpose, and their magnesium is not dosed like a supplement's.
Which to choose: a short cheat sheet
The EU-authorised magnesium claims are the same for every form: they depend only on the dose of elemental magnesium (from 56 mg a day). So compare elemental magnesium and the price of a daily dose, not the promises on the pack.
How it is taken
Makers usually state 200–400 mg of elemental magnesium a day, sometimes split into two doses. Tablets and capsules are taken with water, often with a meal. Do not exceed the dose on the pack: EFSA's tolerable upper level for magnesium from supplements is 250 mg a day on top of food, and higher doses may loosen the stool.
Frequently asked questions
Which form of magnesium is best?
There is no single best. Citrate is cheaper and dissolves well, bisglycinate is usually gentler on the stomach, oxide makes a small tablet. Compare by elemental magnesium per daily dose.
What does elemental magnesium mean?
It is the amount of magnesium itself in the compound. 2000 mg of magnesium citrate, for example, holds about 300 mg of elemental magnesium. Reference intakes and doses are always counted by it.
When is the best time to take magnesium?
There is no fixed time. Many take it in the evening or split the dose in two. Follow the advice on the pack.
Can magnesium be taken with zinc and calcium?
Many complexes are made exactly that way. If you take separate supplements, follow each one's dose and do not exceed the daily amount on the pack.
Can magnesium be taken with coffee?
Yes, though many take them at different times. There is no general rule against it.
Magnesium in the morning or evening?
There is no fixed time; many take it in the evening or split the dose.
Can I take magnesium while pregnant?
Supplements during pregnancy should be agreed with a doctor.
What is magnesium oil?
A magnesium chloride solution for the skin. It is not a food supplement, and its magnesium is not dosed like a tablet's.
Magnesium in the shop
