How to choose a magnesium supplement

Paying more doesn’t get you more magnesium. Pick a form, then compare what 100 mg of magnesium costs.

Try the chooser Which form is which

Five steps

Pick the form
If a doctor or pharmacist named one, use that. Whether forms work differently is a medical question, and we don’t judge it.
Why first: a price only means something next to the same form. Which form is which
Check the label adds up
Look for “figures add up” under the product name, and for an AUST L number.
Why: it’s the one check a label can pass without a lab. “Can’t be double-checked” is common, and not a mark against anyone.
Compare cost per 100 mg
The lowest gets you the same magnesium for less.
Why: price per tablet hides how much magnesium each tablet holds. A sale may beat our price.
Pick what suits you
Tablet, capsule or powder? How many per serve? Anything else in it?
Why: this is mostly what a higher price pays for.
Tested for sport? Find a certificate
If you’re drug-tested for sport, look for a product listed by a sports testing program, such as HASTA.
Right now none of the 15 products here links one.

What a higher price can and can’t buy

In one form, a higher price buys extras, not more magnesium.

It can buy

A brand you know
A bigger or smaller pack
One shop’s price instead of another’s
A format: capsule, powder or chewable
Extra ingredients

It can’t buy

More magnesium. 100 mg is 100 mg.
A different compound. Glycinate at $0.38 per 100 mg is the same compound as glycinate at $0.10.
Numbers that add up. That’s just maths on the label.

Across forms, the cheapest per 100 mg are blends heavy in oxide. That’s chemistry, not a recommendation: oxide is about 60 % magnesium.

What we can and can’t tell you about quality

We can tell you what the label says and whether it adds up. We can’t tell you what’s inside.

We can tell you

What the pack, brand or shop says, with a link
Whether those numbers add up
The AUST L number, as printed
Whether we found a test certificate
What 100 mg of magnesium costs

We can’t tell you

What’s really in the tablet. We don’t test products.
Whether one factory does a better job than another
Whether a product suits you

The rules for AUST L products

Every product here with an AUST L number is a listed medicine.¹ Before it’s listed, the company behind it certifies to the TGA, Australia’s medicines regulator, that it meets the rules. That includes the rules on how it’s made.¹

Listed medicines made in Australia must come from a factory with a TGA licence. If made overseas, the factory needs TGA clearance for good manufacturing practice (GMP).² National rules also set a minimum for each stated ingredient. It applies to the average of a sample of listed tablets or capsules.³

Those rules are the same whatever the price. So within one form, paying more doesn’t buy a higher standard. It buys a brand, a pack size, a format or extra ingredients.^{1, 3}

The TGA doesn’t check each product before it’s sold. It reviews some afterwards and can cancel ones that break the rules. An AUST L number isn’t TGA approval.¹

Products sold as sports foods follow food rules instead, so they don’t have an AUST L number.

Each form at a glance

The lowest and highest cost per 100 mg in each form. Tap a form to see every product in it.

The lowest and highest cost per 100 mg in each form
Form	Listed	Lowest per 100 mg	Highest per 100 mg
Glycinate	5	$0.10 Nature's Ownrecall notice	$0.38 Nutra-Life
Citrate	2	$0.21 Swisse	$0.39 Herbs of Gold
Aspartate	1	$0.54 Blackmores	only one with a figure
Blends	7	$0.036 Cenovis	$0.39 BioCeuticals

Figures, not picks. Prices are the RRP or the usual shelf price; a sale may be lower.

More help

Page text last revised 27 Oct 2026.

Five steps

Pick the form

Check the label adds up

Compare cost per 100 mg

Pick what suits you

Tested for sport? Find a certificate

Try it on the 15 products here