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Protein WorksMinerals

Magnesium Glycinate X3, 90 capsules

£10.99 for 90 capsules at Protein Works. That works out at 1p per 100 mg magnesium, which ranks it 2nd of the 79 magnesium blends and other forms we price across 15 UK retailers.

What it really costs, per 100 mg magnesium1pOne 100 mg dose is our comparison unit for magnesium. It is not a recommendation.
A day1p
A week9p
A month40p
A year£4.92

At one 100 mg dose a day, this pack lasts 2.2 years. A month is 30 days, so twelve of them is not quite a year.

How we worked it out

  • Servings: 90 ÷ 2 per serving = 45
  • In the pack: 45 × 1.81 g = 81.6 g
  • £10.99 ÷ 81.6 g × 100 mg = 1.35p per 100 mg magnesium
  • A week 1.35p × 7 = 9p · a month × 30 = 40p · a year × 365 = £4.92
  • Amount per serving: stated on the label.

The standard dose is a comparison unit, not a recommendation. Always confirm the price on the retailer's site. How we compare everything.

Cheaper magnesium blends and other forms

All 79, ranked →
ZipVitMagnesium 500mgCheapest per 100 mg magnesiumZipVit · 500 mg a serving · 33p a month · a pack lasts 4.9 years1p£19.99View at ZipVit (opens in a new tab)
This productProtein Works · 1.81 g a serving · 40p a month · a pack lasts 2.2 years1pshown above

Switching to the ZipVit pack saves 7p a month at the same 100 mg dose.

Ranked purely by price per 100 mg magnesium. 236 combination products also contain magnesium.

On the label

Magnesium · Blends and other forms
1.81 g per serving (stated on the label)
Pack
90 capsules · 45 servings · 2 capsule(s) a serving
Cost per serving
24p (45 servings in the pack)
More label details
Barcode
5061062522218
Sold by
Protein Works
What the listing says
“90 Capsules” · “Per 2 Capsules” · “[Magnesium ; 1813mg]”
Ingredients

Magnesium Bisglycinate, Magnesium Citrate, Magnesium Malate, Capsule Shell (Hydroxypropyl Methyl Cellulose), Anti-Caking Agent (Magnesium Stearate).

From the Protein Works listing. Check the pack itself if you have an allergy: labels mark allergens in bold.

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One 100 mg dose is our comparison unit, not a recommendation.

Price history

1 price change since 23 September 2026. Checked on 2 days, most recently 9 October 2026.

Lowest recorded
£9.9923 Sept
Highest recorded
£10.999 Oct
First recorded
£9.9923 Sept
Checked on
2 dayssince 23 Sept
Pack price at each check.
  1. Up at Protein Works: £9.99 → £10.99 (+10%)
  2. First checked at Protein Works: £9.99

Questions about this product

How much does Protein Works Magnesium Glycinate X3 cost per 100 mg magnesium?

1p per 100 mg magnesium, from £10.99 for 90 capsules at Protein Works, checked on 9 October 2026.

Is it the cheapest of the magnesium blends and other forms in the UK?

No, it is 2nd of 79. Magnesium 500mg at ZipVit works out at 1p per 100 mg magnesium.

How long does one pack last?

2.2 years at one 100 mg dose. The pack holds 81.6 g in total.

About Protein Works

Founded 2012 · Liverpool, England · Part of Lactalis

Protein Works is a British nutrition company founded in 2012 by Mark Coxhead, Nick Smith and Karl Jacobie. It is based at PW Campus in Speke, Liverpool, which opened in 2025 and replaced several sites in Runcorn.

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