Magnesium supplements: forms and how to compare labels
Why the elemental magnesium figure matters more than the big number on the front, what the common forms are, and how to compare products fairly.
Updated 15 November 2026 · Published by Radiant Life Distributors
Elemental magnesium: the number that matters
Magnesium in supplements is always bound to another compound — citrate, glycinate, oxide and so on. Labels usually show the weight of the whole compound and the amount of magnesium it supplies, often written as "equivalent to magnesium X mg". That second figure, the elemental magnesium, is the one to compare between products.
Example: "Magnesium citrate 500 mg (equivalent to magnesium 80 mg)" supplies 80 mg of magnesium, not 500 mg.
The common forms
| Form | How it's usually sold | Label note |
|---|---|---|
| Magnesium oxide | Tablets | High magnesium content by weight, so tablets can be smaller for the same elemental dose |
| Magnesium citrate | Tablets, powders | Common in powders and combination formulas |
| Magnesium glycinate / bisglycinate | Capsules, powders | An amino acid chelate; often labelled "amino acid chelate" |
| Magnesium chloride | Magnesium oil, flakes, liquids | The form in topical "magnesium oil" sprays and bath flakes |
| Magnesium sulfate | Epsom salts | Usually sold for bathing |
| Magnesium L-threonate, orotate, aspartate | Capsules, combination formulas | Less common forms; check the elemental amount |
Many products combine two or three forms. The label lists each one and the total elemental magnesium.
How to compare magnesium products
- Find the elemental magnesium per serve (tablet, capsule or scoop).
- Divide the price by the number of serves, then by the elemental milligrams, to get a cost per 100 mg of magnesium.
- Check the other ingredients — many "magnesium" products are combination formulas with vitamins, herbs or sweeteners.
- Check the AUST L number on the ARTG (see how to check a supplement).
Magnesium oil and flakes
"Magnesium oil" is not an oil — it is magnesium chloride dissolved in water, which feels slippery on the skin. Flakes are dried magnesium chloride for baths. Our specialist site covers the oils, sprays and flakes in more detail.
Where to buy
Mega Health stocks magnesium tablets, powders, capsules, oils and flakes from several Australian and international brands.
General information only, not medical advice. Supplements are not a substitute for a varied diet. Always read the label and follow the directions for use, and check with your pharmacist or doctor before starting a supplement, especially if you take other medicines, are pregnant or are managing a health condition.
Questions
What is elemental magnesium?
It is the amount of magnesium a supplement actually supplies, as opposed to the weight of the whole magnesium compound. Labels usually show it as "equivalent to magnesium X mg".
What is the difference between magnesium citrate and glycinate?
They are different compounds that carry magnesium. Citrate is common in powders and tablets; glycinate (or bisglycinate) is an amino acid chelate often sold in capsules. Compare them on elemental magnesium per serve.
Is magnesium oil really an oil?
No. It is magnesium chloride dissolved in water, which feels oily on the skin.
How do I compare the price of magnesium supplements?
Work out the cost per serve and divide by the elemental magnesium per serve to get a cost per 100 mg of magnesium.