Which one do I buy?
We won’t pick one for you, but here’s how to narrow it down.
- Pick the form your doctor or pharmacist named.
- In that form, look for labels that add up.
- Compare cost per 100 mg. The lowest gets you the same magnesium for less.
- Pick a format that suits you.
Our chooser does this for you.
Do you say which magnesium to take for sleep or cramps?
No. That’s a health question, and the answer depends on you.
Claims about what supplements do are tightly regulated, so we make none. A pharmacist or doctor can help, especially if you have kidney problems or take other medicines. Once you know the form, we can help you shop: see which magnesium is which.
Is a dearer magnesium better quality?
Not in any way we can see.
In one form, paying more doesn’t get you more magnesium. The AUST L rules are the same at any price, so it doesn’t buy a higher standard either. It buys a brand, a pack size, a format or extras. What we can and can’t tell you about quality.
What does “mostly adds up” mean?
For a blend: the parts we can check add up, but one part can’t be checked.
We check each part of a blend on its own. Often one part is an “amino acid chelate” with no amino acid named, so it has no fixed share. If the rest add up and make at least 50 % of the magnesium, it mostly adds up. The % shows how much we checked.
Is magnesium glycinate the same as bisglycinate?
Yes.
Glycinate, bisglycinate and diglycinate are one compound. It’s about 14 % magnesium, so 1,000 mg gives about 141 mg. With water in it (dihydrate), it’s about 12 %. An “amino acid chelate” is the same thing only if it names glycine.
What does “elemental magnesium” mean?
The magnesium you actually get, not the compound it’s bound to.
It comes after “equivalent to” or “equiv.” in the panel. It’s the number to compare.
Why does my 500 mg tablet say much less magnesium on the back?
Because 500 mg is the whole compound, not the magnesium.
500 mg of oxide gives about 300 mg of magnesium, glycinate about 70 mg, and aspartate about 37 mg. The calculator works it out for any label.
What does “buffered” mean?
Usually glycinate mixed with another compound, often oxide.
Oxide raises the magnesium per tablet. Labels don’t always say what it’s buffered with, so check the panel.
What is “heavy” magnesium oxide?
The same compound as ordinary oxide, made as a denser powder.
Heavy and light oxide are both about 60 % magnesium.
Does an AUST L number mean the TGA has checked the product?
Not the product itself.
AUST L means the product is a listed medicine. It may contain only pre-approved, low-risk ingredients. It may make only pre-approved, low-level claims. Its sponsor, the company behind it, certifies that it meets the rules. And the TGA, Australia’s medicines regulator, did not evaluate this particular product before it went on sale. So AUST L tells you it’s on the register (the ARTG), not what’s in the bottle.
What does “third-party tested” mean here?
That we opened a certificate or program listing for it. A claim on the pack isn’t enough.
Right now none of the 15 products links one. Many brands test without publishing results, so ask the brand.
Why do so many products say “can’t check”?
Because many labels give only one of the two figures we need.
Many panels print only the magnesium, or an unnamed “amino acid chelate”. Both are common, and neither is a mark against the product.
Why are oxide blends the cheapest per 100 mg?
Chemistry. Oxide is about 60 % magnesium, so less of it carries the same magnesium.
Glycinate is about 14 %, so it takes over four times as much. That isn’t a recommendation: we don’t judge how forms behave in the body.
Why don’t you show sale prices?
Because a fair comparison needs a price that holds still.
Sales change weekly and differ between shops. So we use the recommended retail price (RRP), or the regular shelf price if there’s no RRP. You may well pay less: a sale just lowers the cost while it lasts.
Why do product pages say “the listing”, not “the label”?
Because we often read a shop’s listing, not the pack.
Listings are typed by hand and can differ from the pack. Your pack shows different figures? A photo helps us fix it: see corrections.
How often are the figures checked?
Every week, a few products at a time.
Each week we re-check the oldest prices and labels, and add new products. Product pages show the dates.
Why isn’t my product listed?
We just haven’t got to it yet.
We add a few at a time. Suggest one at [email protected]. Meanwhile, the calculator works for any label.
Do you take money from brands or retailers?
No.
We earn nothing: no ads, no affiliate links, no free product. No brand or retailer pays for inclusion, placement or marks. See how we’re funded.
Page text last revised 27 Oct 2026.