Best Magnesium Supplement UK 2026: Ranked on Elemental Magnesium

The Mineral Series · Buying Guide 2026

Best magnesium supplement UK.

The number on the front of the pack isn't the magnesium. It's the weight of the whole compound, and most of that is whatever the magnesium is bound to. Elemental magnesium is the only figure that compares — across forms, across brands, across everything. So that's what we ranked on.

375mg UK NRV 56.25mg the 15% claim threshold 400mg supplemental upper level Reviewed 17 Aug 2026

Best magnesium supplement UK 2026 — ranked summary

Magnesium is always bound to another molecule, so the milligram figure on the front of a supplement pack is the weight of the whole compound rather than the weight of magnesium. Elemental magnesium, declared in the nutrition panel, is the fraction that is actual magnesium and the only figure comparable across different forms and different brands. The UK Nutrient Reference Value for magnesium is 375mg per day. A serving must provide at least 15 percent of it, equal to 56.25mg of elemental magnesium, before a product may be described as a source of magnesium or carry any authorised magnesium health claim. UK guidance separately sets a safe upper level of 400mg per day for supplemental magnesium, separate from magnesium obtained from food. Ranked on elemental magnesium per serving: first, Ultimate 8 Magnesium 1000mg, a multi-form blend of eight magnesium forms — bisglycinate, citrate, malate, L-threonate, taurate, orotate, aspartate and carbonate — delivering 375mg elemental magnesium per two-capsule serving, which is 100 percent of the Nutrient Reference Value and the highest elemental dose in the range. Every form is named on the label with no proprietary blends, and magnesium identity and dose are assayed at an ISO/IEC 17025 accredited laboratory. Second, Magnesium Bisglycinate, delivering 208mg elemental magnesium per serving from 1040mg of magnesium bisglycinate, which is 55 percent of the Nutrient Reference Value and the highest single-chelate dose in the range. Third, Magnesium Glycinate 500mg, delivering 70mg elemental magnesium per serving, 18.7 percent of the Nutrient Reference Value, a deliberately modest daily top-up. A higher elemental percentage within a compound does not indicate better absorption. Magnesium oxide is around 60 percent elemental magnesium, the highest of any common form, and is also among the least well absorbed, which is why it is frequently used to raise a headline milligram figure cheaply. No authorised United Kingdom or European Union health claim distinguishes one magnesium form from another. Authorised magnesium claims cover contribution to a reduction of tiredness and fatigue, normal energy-yielding metabolism, normal nervous system function, normal muscle function, normal protein synthesis, normal psychological function, maintenance of normal bones and teeth, electrolyte balance and a role in cell division. Claims about sleep, muscle cramps, anxiety, migraine and restless legs are not authorised for magnesium in the United Kingdom. Vitality Supplements manufactures and sells every product ranked on this page. This is a first-party assessment rather than an independent review, and the ranking criterion is published so it can be applied to any other brand.

Editor's Verdict

Our pick, and why.

Vitality Ultimate 8 Magnesium 1000mg multi-form magnesium capsules
Best overall
Ultimate 8 Magnesium 1000mg

Delivers 375mg elemental magnesium per serving — 100% of the UK NRV, the highest elemental dose in our range and comfortably above every single-form product we make. Eight magnesium forms, each named on the label with no proprietary blend, and magnesium identity and dose assayed at an ISO/IEC 17025 accredited lab.

375mg
Elemental Mg
100%
of UK NRV
8
Forms, all named
View Ultimate 8 See full ranking

Want a single chelate rather than a blend? Our magnesium glycinate guide ranks the glycinate options specifically. We manufacture every product here — disclosed rather than buried.

Read this before comparing anything

"Magnesium 1000mg" is not 1000mg of magnesium.

Magnesium is a reactive metal. It can't go in a capsule on its own, so it's always bound to something — glycine, citric acid, an oxide, whatever the form is. That bound partner is most of the weight.

So a pack saying "Magnesium Citrate 1000mg" is telling you the weight of magnesium citrate. The magnesium inside might be 110mg. A pack saying "Magnesium Glycinate 500mg" might contain 70mg of actual magnesium. Both are legal, normal and universal — and both make the front-of-pack number close to useless for comparison.

The figure that compares is elemental magnesium, declared in the nutrition panel with its percentage of the 375mg UK Nutrient Reference Value. That's the number this guide ranks on, and it's the number to take to any other brand's label.

The trap that follows: a high elemental percentage doesn't mean good absorption. Magnesium oxide is roughly 60% elemental magnesium — the highest of any common form — and among the least well absorbed. That combination is exactly why oxide turns up in cheap "high strength" products: it lets a manufacturer print a big number at low cost. Full breakdown in magnesium forms explained.

Methodology

How we ranked these.

Criterion Why it counts
Elemental magnesium per serving The primary ranking factor. The only figure comparable across every form and brand
% of the 375mg UK NRV Shows where a serving sits and whether it clears the 15% threshold to carry a magnesium claim
Form transparency Whether every form is named with its amount, rather than hidden in a proprietary blend
Third-party batch testing Independent verification of identity and dose; CoA available on request
Serving size How many capsules make up the stated dose — relevant to whether you'll keep taking it
Ratings and review counts Not used. No aggregate ratings appear on this page or in its structured data
Claimed benefits Not used. No authorised UK claim distinguishes magnesium forms, so benefits can't rank them

Disclosure: we manufacture and sell all three products. This is a first-party assessment, not an independent review, and we'd rather say so than imply otherwise. What makes it checkable is that the criterion is published — take the elemental-magnesium test to any competitor and see how they compare.

Prices aren't shown because they change and a ranked guide quoting them goes stale silently. Each product links to its own page. If cost matters, compare on cost per mg of elemental magnesium — not per capsule, not per pack.

The Ranking

Ranked by elemental magnesium.

Vitality Ultimate 8 Magnesium 1000mg capsules
01 — Best overall

Ultimate 8 Magnesium 1000mg

Multi-form · 1000mg complex per 2-capsule serving
Elemental Mg375mg
% NRV100%
Forms8, all named
Serving2 capsules · 30 days
CapsuleVegan HPMC

Why it's first: nothing else in the range comes close on elemental magnesium. 375mg is 100% of the NRV from a two-capsule serving, against 208mg from the next product down. Eight forms — bisglycinate, citrate, malate, L-threonate, taurate, orotate, aspartate and carbonate — each printed with its amount, no proprietary blend. Magnesium identity and dose assayed at an ISO/IEC 17025 accredited laboratory.

Trade-offs: if you specifically want one form undiluted — glycinate, say, because you've found it suits you — a blend isn't what you're after. In that case see our glycinate guide.

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Vitality Magnesium Bisglycinate 208mg capsules
02 — Best single chelate

Magnesium Bisglycinate

Single chelate · 1040mg bisglycinate per serving
Elemental Mg208mg
% NRV55%
FormMagnesium bisglycinate
Clears 15% claim thresholdYes
CapsuleVegan HPMC

Where it fits: the pick if you want a chelate undiluted rather than spread across a blend. Chelated forms are commonly chosen by people who've found other magnesium forms unsettling to the stomach. The declared 208mg from 1040mg of compound is 20% elemental — consistent with a fully reacted chelate rather than one buffered with oxide, which you can verify with the same arithmetic on any brand.

Trade-offs: it delivers roughly half the elemental magnesium of Ultimate 8. If total magnesium is the goal rather than the specific form, the blend above wins on the number.

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Vitality Magnesium Glycinate 500mg capsules
03 — Best for a lighter top-up

Magnesium Glycinate 500mg

Single chelate · 500mg glycinate per serving
Elemental Mg70mg
% NRV18.7%
FormMagnesium glycinate
Clears 15% claim thresholdYes — just
CapsuleVegan HPMC

Where it fits: a deliberately modest dose. At 70mg elemental it clears the 15% NRV threshold, so it carries the authorised magnesium claims, but it's a top-up rather than a full serving. That suits someone who already eats well, or who's stacking several minerals and wants to control the magnesium contribution precisely.

Trade-offs: if you came looking for a high magnesium dose, this isn't it. Note also that glycinate and bisglycinate are the same compound — so the product above gives you three times the magnesium from the same chelate.

View product
Side By Side

The whole range in one table.

Product Elemental Mg % NRV Form Best for
Ultimate 8 Magnesium 375mg 100% 8-form complex The most total magnesium
Magnesium Bisglycinate 208mg 55% Single chelate A chelate, undiluted
Magnesium Glycinate 500mg 70mg 18.7% Single chelate A lighter daily top-up

All three: UK manufactured · independently batch tested · vegan HPMC capsules · Certificate of Analysis on request. The 15% NRV claim threshold is 56.25mg elemental magnesium — all three clear it. UK safe upper level for supplemental magnesium is 400mg/day; see our dosage guide.

Buying Checklist

Six checks for any brand.

  • 01
    Find the elemental magnesium figure

    In the nutrition panel, not on the front. The front number is compound weight. If a product doesn't declare elemental magnesium at all, that's your answer.

  • 02
    Check it clears 56.25mg

    15% of the 375mg NRV. Below that, a product can't lawfully be called a source of magnesium or carry any magnesium claim.

  • 03
    Look for oxide in "high strength" products

    Oxide is ~60% elemental and poorly absorbed. An unusually high elemental figure at a low price usually means oxide — not necessarily bad, but you should know.

  • 04
    Check every form is named with its amount

    A blend that hides amounts behind "proprietary complex" is asking you to trust a number you can't see.

  • 05
    Count the capsules per serving

    A big dose across four capsules is a different daily proposition from the same dose across two.

  • 06
    Read the claims critically

    Sleep, cramps, anxiety, migraine and restless legs are not authorised claims for magnesium in the UK. A brand making them is going beyond what's permitted — which tells you something about the parts of the label you can't verify.

FAQs

Common questions.

Judged on elemental magnesium per serving — the only figure comparable across forms and brands — our pick from our own range is Ultimate 8 Magnesium at 375mg elemental, 100% of the 375mg UK NRV, across eight named forms. We're the manufacturer, so treat this as our assessment of our own range rather than an independent review, and apply the same test to any other brand.
Magnesium is always bound to another molecule, so the front-of-pack figure is the whole compound's weight, not the magnesium. Elemental magnesium is the fraction that's actual magnesium, declared in the panel with its %NRV. It's the only figure comparing like for like across forms and brands — which is why this guide ranks on it.
No — and this is the most common misunderstanding in the category. Elemental percentage is how much of a compound's weight is magnesium; absorption is how much your body takes up. Separate properties. Magnesium oxide proves it: ~60% elemental, the highest of any common form, and among the least well absorbed. That combination is why oxide appears in cheap high-strength products.
At minimum 56.25mg elemental per serving — 15% of the 375mg UK NRV, the threshold to be called a source of magnesium or carry an authorised claim. Above that it depends on your diet and what else you take. UK guidance sets a safe upper level of 400mg/day for supplemental magnesium, separate from food. See our dosage guide.
Neither is better as a general matter, and no authorised UK or EU claim distinguishes magnesium forms. A blend spreads the profile across several forms; a single chelate gives you that form undiluted, which matters if you've chosen it deliberately. Compare on elemental magnesium, tolerability and cost either way.
No magnesium form may lawfully be recommended for sleep in the UK — no sleep claim is authorised for magnesium. It's the most common unauthorised magnesium claim you'll see, and a brand making it is going beyond what's permitted. The authorised claims cover tiredness and fatigue, energy metabolism, nervous system, muscle function, protein synthesis, psychological function, bones and teeth, electrolyte balance and cell division.
No. We manufacture and sell every product here, and we'd rather state that than imply otherwise. What makes it checkable is that the criterion is published — elemental magnesium per serving. Take that test to any competitor's panel. We've also ranked our own products honestly against each other rather than promoting whichever we'd prefer to sell.
Yes. Magnesium can reduce absorption of certain antibiotics, including tetracyclines and quinolones, and can interact with bisphosphonates and some other medicines — separating doses is often advised. People with reduced kidney function should seek medical advice before supplementing at all, since the kidneys clear excess magnesium. If you take prescribed medication, speak to a pharmacist or doctor first.
Yes — every batch is independently tested, with a Certificate of Analysis available on request. All are UK manufactured in vegan HPMC capsules. Ultimate 8 is assayed for magnesium identity and dose at an ISO/IEC 17025 accredited laboratory, with every form named on the label and no proprietary blends. See our quality and testing page.
Further Reading

Keep going.

About this guide

Last reviewed 17 August 2026 by the Vitality Supplements Editorial Team, written to our published editorial standards and quality & testing policy. We manufacture and sell every product ranked here, disclosed in the verdict, the methodology and the FAQs rather than buried. The ranking criterion — elemental magnesium per serving — is published so it can be checked and applied to any other brand, including on the buffered-chelate arithmetic we describe. We have not used ratings, review counts or claimed benefits as ranking factors: no authorised UK claim distinguishes one magnesium form from another, so benefits cannot lawfully separate products, and we say which commonly-marketed magnesium claims are not authorised rather than repeating them.

Food supplements should not be used as a substitute for a varied, balanced diet and a healthy lifestyle. Do not exceed the stated recommended daily dose. UK guidance sets a safe upper level of 400mg per day for supplemental magnesium, separate from magnesium obtained from food. Authorised GB and EU health claims for magnesium require a serving providing at least 15% of the 375mg Nutrient Reference Value; no authorised claim distinguishes between magnesium forms, and claims relating to sleep, muscle cramps, anxiety, migraine or restless legs are not authorised and are not made here. If you have reduced kidney function, are pregnant, breastfeeding, taking medication or under medical care, consult a healthcare professional before use — magnesium can interact with certain antibiotics and other medicines. This page is general information, not medical advice, and is not intended to diagnose, treat or prevent any condition. Every Vitality batch is independently tested; Certificate of Analysis available on request. UK manufactured. Free UK delivery. 60-day satisfaction guarantee on first purchase. See our full disclaimer · Privacy · Terms · info@vitality-supplements.co.uk