Best Magnesium Supplements UK (2026): Our Top Picks
Magnesium deficiency is one of the most common nutritional shortfalls in the UK. We break down the best forms, what to look for, and our top recommended products.
Why magnesium matters more than you think
Magnesium is involved in over 300 enzymatic reactions in the body — from energy production to muscle contraction to sleep regulation. Yet surveys consistently show that a large proportion of UK adults fail to meet the recommended daily intake. It's one of the few supplements where the evidence for broad benefit is genuinely strong.
Which form of magnesium is best?
Not all magnesium supplements are created equal. The form (or "chelate") determines how well it's absorbed and what side effects it might cause.
Magnesium glycinate
This is our top recommendation for most people. It's bonded to glycine — an amino acid — which significantly improves absorption and makes it much gentler on the digestive system. If you've had issues with other forms causing loose stools, glycinate is the one to try.
Magnesium citrate
Good bioavailability and widely available. Has a mild laxative effect at higher doses, which some people find useful if they also have occasional constipation. A solid all-rounder.
Magnesium oxide
The most common form in cheap supplements. Bioavailability of around 4% — essentially a waste of money. Avoid.
What to look for on the label
Check the "elemental magnesium" amount — not just the total compound weight
Look for glycinate or citrate forms over oxide or carbonate
A good daily dose is 200–400mg elemental magnesium
Check for unnecessary additives or fillers in budget options
Our top pick: Simply Supplements Magnesium Glycinate 400mg
For most UK shoppers, Simply Supplements Magnesium Glycinate represents excellent value without compromising on form quality. At under £15 for 60 capsules, it's competitively priced and uses the superior glycinate form that most premium brands charge a premium for.
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