Buying magnesium: compare the price per mg properly
Futures Nutrition Editorial Team · 10 August 2026
Buying magnesium: compare the price per mg properly
10 August 2026
Two packs side by side, €9.90 and €14.90 – and the cheaper one is the more expensive. That is not a numerical trick but the normal case with magnesium. Neither the pack price nor the price per tablet can be compared between two products, because both figures leave open how much magnesium is actually inside. The purchase only becomes comparable through a single measure: the price per 100 mg of elemental magnesium.
That number appears on no pack. It can, however, be worked out from three details that have to be printed there – in less than a minute.
Magnesium contributes to normal muscle function.
The calculation that makes two products comparable
You need the pack price, the number of units and the milligrams of magnesium per tablet from the nutrition table – not the weight of the compound from the front of the pack.
Price per 100 mg = pack price ÷ (units × mg per tablet) × 100
Three examples, exactly as they can stand side by side on a shelf:
| Example | Pack price | Units | Magnesium per tablet | Magnesium per pack | Price per 100 mg |
|---|---|---|---|---|---|
| A | €9.90 | 120 | 100 mg | 12,000 mg | €0.08 |
| B | €14.90 | 120 | 150 mg | 18,000 mg | €0.08 |
| C | €7.90 | 60 | 100 mg | 6,000 mg | €0.13 |
A and B differ by five euros per pack and deliver magnesium at exactly the same price. C is the cheapest pack on the shelf and the most expensive magnesium in the comparison – around 60 % dearer per milligram.
Anyone who does the calculation once for the products they buy regularly rarely needs it again. It only changes when the price or the formulation changes.
Why the number on the front is no use
In food supplements magnesium never occurs on its own; it is always bound to a partner – to glycine, citric acid, malic acid or a mineral partner. That partner is on the scales too. Of 1,000 mg of magnesium bisglycinate around 140 mg is magnesium, of 1,000 mg of magnesium oxide around 600 mg.
That is why "500 mg magnesium citrate" and "500 mg magnesium" are two entirely different statements, and why a large number on the front is not an argument. The elemental share differs considerably from compound to compound: bisglycinate around 14 %, citrate around 16 %, oxide around 60 %.
For a price comparison one simple rule follows: calculate exclusively with the "magnesium" line from the nutrition table. That figure always refers to elemental magnesium, regardless of the form – which makes it the only number that means the same thing across products.
What has to be on the label
A food supplement sold in the EU is governed by Directive 2002/46/EC and the EU Food Information Regulation 1169/2011, implemented in each country's national law. What is missing is not missing for lack of space – it belongs there:
- The description "food supplement". Not "vital substance complex", not "mineral formula" on its own.
- The compound in the list of ingredients. Only the magnesium compounds listed in the EU are permitted. If it merely says "magnesium" and the compound cannot be found anywhere, the declaration is incomplete.
- The recommended daily portion – that is, whether a daily portion consists of one, two or three tablets.
- The content per daily portion in mg and as a percentage of the nutrient reference value (NRV). The NRV for magnesium is 375 mg per day; 150 mg therefore corresponds to 40 %.
- The warning not to exceed the stated recommended daily dose, the note to keep the product out of the reach of small children, and the statement that it is not a substitute for a balanced diet.
The most common stumbling block is in the third line: "per daily portion" is not "per tablet". A product with 300 mg per daily portion may mean three tablets of 100 mg each. For a price comparison, therefore, always reduce the figure to the single tablet – or go straight to the cost per day.
Cost per day instead of price per pack
If you know how much magnesium you want to supplement daily, that is the most practical measure. The German Federal Institute for Risk Assessment recommends a maximum of 250 mg of magnesium per day from food supplements, spread over at least two servings. Those 250 mg refer to supplementation alone, whereas the 375 mg of the NRV is a labelling reference value for total intake from diet and supplement – the two figures do not contradict each other.
With example B above and 150 mg a day, supplementation costs around 12 cents daily; with example C and the same amount, around 20 cents. Over a year that is roughly €45 against roughly €72 – for an identical nutrient.
Additives: what is usual and what stands out
A tablet never consists of the nutrient alone. Excipients are added so that the powder can be pressed at all and so that the tablet leaves the machine undamaged. They have to appear in the list of ingredients together with their function.
| Ingredient | Function | Assessment |
|---|---|---|
| Microcrystalline cellulose | Bulking agent | plant-based standard, makes pressing possible |
| Magnesium salts of fatty acids (magnesium stearate) | Anti-caking agent | usual trace amount; contributes nothing appreciable to the declared magnesium |
| Silicon dioxide | Anti-caking agent | keeps the powder free-flowing |
| Hydroxypropyl methylcellulose | Coating or capsule material | plant-based, alternative to gelatine |
| Sweeteners, flavourings, acidity regulators | Taste | typical for powders and effervescent tablets, unnecessary in tablets |
Two things here are of practical relevance. First: anyone buying vegan looks at the capsule shell – gelatine is of animal origin, cellulose is not. Second: effervescent tablets and sticks often contain sodium, because the fizz comes from a carbonate; anyone watching their sodium intake will find the figure in the nutrition table.
Advertising statements such as "free from additives", by contrast, say little. Permitted anti-caking agents in trace amounts are not a quality defect, and a product without a bulking agent usually needs a capsule instead of a tablet. What is informative is not the slogan but the list of ingredients beneath it.
Terms without fixed content
A few words sound like a seal of approval and are none:
- "High strength" is not legally defined. The milligram figure per daily portion says everything the term promises.
- "Chelate" describes the form of the bond, not an effect. Authorised claims relate to the nutrient magnesium, not to a particular compound – so one form is not "more effective" than another; they differ in elemental content, solubility and tolerability.
- "Laboratory tested" without stating what was tested for is a statement about nothing. It only becomes informative once the test parameters are named.
What our products declare
Our magnesium bisglycinate 150 mg supplies 150 mg of elemental magnesium per tablet – 40 % of the nutrient reference value – with 120 tablets per pack. For the calculation above that is 18,000 mg of magnesium per pack; the current price on the product page divided by 180 gives the price per 100 mg.
With combination products such as hawthorn + magnesium a pure price comparison is misleading: there you are also paying for the second ingredient, and the magnesium share per daily portion is smaller. Such products are sensibly compared only with other combinations, not with a pure magnesium product. An overview can be found in the minerals category.
Food supplements are not a substitute for a balanced and varied diet and a healthy lifestyle.
The short version for the shelf
- Open the nutrition table, look for the "magnesium" line in mg.
- Check how many tablets that figure refers to.
- Divide the pack price by the total amount of magnesium, times 100.
- Skim the list of ingredients: compound named, capsule shell suitable, no ingredients you do not want.
- Only then look at the front of the pack – that is advertising, not a basis for comparison.
Frequently asked questions
Is the more expensive product the better one?
Not automatically. The price per 100 mg of elemental magnesium is the basis for comparison; beyond that, products differ in tolerability, tablet size and additives. The authorised claims for magnesium apply equally to all of them.
Is the large pack worth it?
Usually yes, with one caveat: work out how long it lasts at your daily portion and compare that with the best-before date. A pack for 400 days that expires in 200 is not cheap but half wasted.
How do I tell how much magnesium is really in a tablet?
From the nutrition table. The figure there is elemental magnesium and legally binding. If a noticeably larger number appears on the front, it refers to the weight of the compound – that is, including the binding partner.
How much magnesium should the daily portion contain?
That depends on what the diet already provides. The reference value on the label is 375 mg for total intake; the recommendation for food supplements alone is 250 mg per day.
Matching products from our range
Sources: Regulation (EU) No 432/2012 (authorised claims); Regulation (EU) No 1169/2011, Annex XIII (nutrient reference values); Directive 2002/46/EC, Annex II (permitted mineral compounds); German Food Supplements Ordinance (NemV), § 4; German Federal Institute for Risk Assessment, "BfR assesses maximum daily levels for magnesium in food supplements", 2017. Back to the Magazine
