Best Magnesium Supplement in the UK (2026): Complete Buying Guide
The best magnesium supplement for most people in the UK is Solgar Magnesium Glycinate: 240 mg of magnesium as bisglycinate in 2 capsules, £0.53 a day at Solgar’s UK list price, sold by Amazon UK. That is under the NHS’s 400 mg and the EU’s 250 mg safety line for supplements. It is not the cheapest glycinate: we chose it because it is bisglycinate only and Amazon UK sells it itself. For a lower cost, Lamberts’ bisglycinate gives 150 mg a capsule.
By Erin Rose Updated October 15, 2026 How we chose
Our pick for most people in the UK
Solgar Magnesium Glycinate
Pure magnesium bisglycinate, sold by Amazon UK
- Magnesium
- 240 mg a serving2 capsules, 64% NRV
- A day
- £0.53one serving, Solgar’s UK list price
- Form
- Bisglycinate onlyno magnesium oxide in the ingredients
- UK safety line
- Under all threeNHS 400 mg, EU 250 mg, US 350 mg
- Bottle
- 60 capsules, £15.99Solgar’s UK list price
- Per 300 mg
- £0.67to compare with others
Our take
Why we pick it Two capsules give 240 mg of magnesium, all as bisglycinate (glycinate). That is under the 250 mg a day the EU’s food safety agency (EFSA) sets as the safe limit for magnesium from supplements, and well under the 400 mg the NHS says is unlikely to cause harm. Amazon UK sells and ships it itself, not a reseller. Glycinate is the form most people ask for and is often called gentle on the stomach.
What to know It is not the cheapest. Lamberts’ bisglycinate costs £0.40 per 300 mg of magnesium against £0.67 for this one. We found no UK magnesium product on a public testing list we could read (more below), so this pick rests on the label, the dose and the seller.
Label and testing
We found no UK magnesium product on USP Verified, NSF/ANSI 173 or Informed Sport that we could confirm. We could not open the Informed Sport and Informed Choice registries (run from the UK) on October 15, 2026, so we claim no listing for any product here. Magnesium (as bisglycinate) 240 mg, 64% NRV, per 2 capsules; no other magnesium form in the ingredients (Amazon listing, read October 15, 2026).
Our picks at a glance
Two more picks for different needs. Every product on this page was in stock on Amazon.co.uk with a UK delivery address on October 15, 2026. Costs use each brand’s own UK price, because Amazon’s changes daily.
- A lower cost, and you set the dose Lamberts Gentle Magnesium Bisglycinate
- The lowest cost per mg Lamberts MagAsorb Magnesium Citrate 150 mg
A lower cost, and you set the dose
Lamberts Gentle Magnesium Bisglycinate
Pure bisglycinate from a UK brand
- Magnesium
- 150 mg a capsule40% NRV; take 1 or 2
- A capsule
- £0.20Lamberts’ UK list price
- Form
- Bisglycinate only
- Bottle
- 60 capsules, £11.95Lamberts’ UK list price
- Per 300 mg
- £0.40
- Seller
- A pharmacy resellerstock was low when we checked
Our take
150 mg of magnesium as bisglycinate in each capsule, so one capsule is a light dose and two (300 mg) is still under the NHS’s 400 mg. It costs £0.40 per 300 mg at Lamberts’ own price, less than our pick. On Amazon UK it is sold by a pharmacy reseller, not Amazon, and only a few were left when we checked on October 15, 2026.
Label and testing
Magnesium (as bisglycinate) 150 mg per capsule, 1 to 2 a day (Lamberts' own page, read October 15, 2026). Not found on a public testing list we could read.
The lowest cost per mg
Lamberts MagAsorb Magnesium Citrate 150 mg
Magnesium citrate, 150 mg a tablet
- Magnesium
- 150 mg a tablet40% NRV; take 1 or 2
- A tablet
- £0.13Lamberts’ UK list price
- Form
- Citrateabsorbed better than oxide in small studies
- Bottle
- 180 tablets, £22.95Lamberts’ UK list price
- Per 300 mg
- £0.26
- Seller
- A resellerdispatched by Amazon
Our take
At list price, citrate costs less per mg than glycinate, and this is the cheapest per mg of the UK products we priced: £0.26 for 300 mg. In small studies citrate was absorbed better than oxide. At higher doses it can loosen stools; if it does, switch to a glycinate. No trial shows glycinate works better than citrate for general use.
Label and testing
Magnesium (as citrate) 150 mg per tablet, 1 to 2 a day (Lamberts' own page, read October 15, 2026). Not found on a public testing list we could read.
How to Choose: Quick Decision Matrix
| Your situation | What to buy |
|---|---|
| You want one magnesium supplement | Solgar Magnesium Glycinate, £0.53 a day for 240 mg (our pick) |
| You want a lower cost, still glycinate | Lamberts Gentle Magnesium Bisglycinate, £0.20 a capsule for 150 mg (above) |
| You want the lowest cost per mg | Lamberts MagAsorb Magnesium Citrate 150 mg, £0.26 per 300 mg (above) |
| You want 200 mg in one tablet | Solgar Magnesium Citrate, 200 mg a tablet. The label’s 2-tablet serving is 400 mg (107% NRV), over EFSA’s 250 mg; 1 tablet stays under it. |
| You want a small glycinate capsule | Pure Encapsulations Magnesium Glycinate 120 mg, 120 mg a capsule; sold on Amazon UK only as a 2-pack, and we could not read a UK price |
| You already use Doctor’s Best | Doctor’s Best High Absorption Magnesium, 200 mg in 2 tablets; sold in the UK by an importer. Its label allows 2 tablets twice a day (400 mg). |
| You want a powder to mix in water | Natural Calm (Natural Vitality), a citrate powder; imported, and we did not read the UK tub’s label |
| You want L-threonate | Double Wood Magnesium L-Threonate, about 144 mg of magnesium in 4 capsules; sold by an importer; little human evidence |
What’s Different When You Buy Magnesium in the UK
| Who says it | Supplement limit | What it means |
|---|---|---|
| EFSA (EU food safety agency) | 250 mg | The safe upper limit for magnesium from supplements, from age 4. Set because more can cause mild diarrhoea. |
| US NIH | 350 mg | The US upper limit for magnesium from supplements and medicines, from age 9. |
| NHS (UK) | 400 mg | “Having 400mg or less a day of magnesium from supplements is unlikely to cause any harm.” It comes from the UK expert group’s 2003 guidance level. |
- You need less than an American, on paper. The NHS says 300 mg a day for men and 270 mg for women (ages 19 to 64). The US figure is 400 to 420 mg for men. EFSA says 350 mg for men and 300 mg for women. The NHS says most people can get what they need from food.
- Read the % NRV. UK labels show magnesium as a share of 375 mg. Our pick is 64% NRV. A product at 100% NRV gives 375 mg a day, which is over EFSA’s 250 mg.
- Check for oxide in “bisglycinate”. Three UK listings we read name bisglycinate but also contain magnesium oxide, the cheap form that was about 4% absorbed in one study. Look at the words in brackets on the magnesium line. All three picks above are one form only.
- The US favourites are not here. Nature Made, Thorne, KAL, Vitamin Shoppe and BulkSupplements glycinates had no Amazon UK listing. Some US brands reach Amazon UK through importers; their UK labels may differ, so read the tub.
- No UK product on a testing list we could confirm. Informed Sport and Informed Choice are UK-run programmes, but we could not open their registries, and we found no Solgar, Lamberts or Pure Encapsulations magnesium on USP or NSF lists. A “tested” claim on a label, with no programme named, is the brand’s own word.
| Item | Value |
|---|---|
| Lamberts MagAsorb Magnesium Citrate 150 mg | £0.26 |
| Solgar Magnesium Citrate | £0.39 |
| Lamberts Gentle Magnesium Bisglycinate | £0.40 |
| Solgar Magnesium Glycinate | £0.67 |
Every Magnesium Product We Checked on Amazon UK
| Product | Magnesium | Form | Per 300 mg | Sold by | Buy |
|---|---|---|---|---|---|
| Solgar Magnesium Glycinate | 240 mg / 2 capsules (64% NRV) | bisglycinate | £0.67 | Amazon | Check price |
| Lamberts Gentle Magnesium Bisglycinate | 150 mg / 1 capsule (40% NRV) | bisglycinate | £0.40 | a pharmacy reseller (medino) | Check price |
| Pure Encapsulations Magnesium Glycinate 120 mg | 120 mg / 1 capsule (32% NRV) | glycinate | — | Pattern UK (reseller) | Check price |
| Doctor's Best High Absorption Magnesium | 200 mg / 2 tablets (53% NRV) | glycinate lysinate chelate | — | an importer selling as hello_health on Amazon | Check price |
| Lamberts MagAsorb Magnesium Citrate 150 mg | 150 mg / 1 tablet (40% NRV) | citrate | £0.26 | a reseller (Health Plus More) | Check price |
| Solgar Magnesium Citrate | 400 mg / 2 tablets (107% NRV) | citrate | £0.39 | Amazon | Check price |
| Natural Vitality Natural Calm Magnesium Powder, Unflavoured | see the tub | citrate powder | — | an importer (MALMO) | Check price |
| Double Wood Magnesium L-Threonate | 144 mg / 4 capsules (38% NRV) | L-threonate | — | an importer (Drezz2UStore) | Check price |
How We Chose
Our US guide picks the top-scoring glycinate on a public testing list. No UK product met that test, so we used the same order of checks with what the UK shopper can verify:
- Sold in the UK. We opened every product on Amazon.co.uk with a UK delivery address on October 15, 2026 and kept only those you could add to the basket.
- One form, stated on the label. Glycinate or citrate, with no magnesium oxide mixed in.
- A dose under the safety lines. One serving at or under EFSA’s 250 mg, or easy to split.
- A trustworthy seller. Sold by Amazon or a pharmacy, not an unknown importer, where we had the choice.
- Cost per 300 mg at the brand’s own UK price.
Facts about forms and research are the same in every country; see magnesium forms compared and the UK dosage guide.
Frequently Asked Questions
What is the best magnesium supplement in the UK?
For most people, Solgar Magnesium Glycinate: 240 mg of magnesium as bisglycinate in 2 capsules, £0.53 a day at Solgar’s UK list price, sold by Amazon UK. For a lower cost, Lamberts Gentle Magnesium Bisglycinate gives 150 mg a capsule.
How much magnesium do I need a day in the UK?
The NHS says 300 mg a day for men and 270 mg for women aged 19 to 64, and that you should be able to get it from food. EFSA, the EU food safety agency, sets 350 mg for men and 300 mg for women. UK magnesium dosage guide.
Is 400 mg of magnesium too much?
From supplements, the NHS says 400 mg or less a day is unlikely to cause harm, and that more than 400 mg can cause diarrhoea. EFSA’s safe limit for magnesium from supplements is lower, 250 mg a day, and the US limit is 350 mg. Food does not count toward any of these.
What does % NRV on a UK magnesium label mean?
NRV is the nutrient reference value printed on UK and EU labels. For magnesium it is 375 mg. So 100% NRV is 375 mg, which is over EFSA’s 250 mg limit for supplements. A label at about 67% NRV or less is under it.
Can I buy Nature Made or Thorne magnesium glycinate in the UK?
Not on Amazon UK when we checked: the US Nature Made, Thorne, KAL, Vitamin Shoppe and BulkSupplements glycinates had no UK listing. Doctor’s Best and Double Wood are sold by importers. That is why the UK picks differ from our US guide.
Should I buy glycinate or citrate in the UK?
Either works for general use; no trial shows one is better. In the UK, at list price, citrate is the cheaper buy: Lamberts MagAsorb Magnesium Citrate 150 mg costs £0.26 per 300 mg against £0.67 for our glycinate pick. Choose glycinate if citrate loosens your stools. UK forms compared.
Which magnesium is best for sleep?
No form is proven best. Three small trials in older adults used 320 to 729 mg a day of oxide, citrate and effervescent tablets, and a 2021 review found people fell asleep about 17 minutes faster, with low-quality evidence. A 2025 trial of 250 mg as bisglycinate found a small effect. The 320, 500 and 729 mg doses are above EFSA’s 250 mg line, and 500 and 729 mg are above the NHS’s 400 mg.
More UK Magnesium Guides
- How much magnesium per day in the UK · magnesium forms compared
- US research pages that apply anywhere: magnesium and sleep · side effects · glycinate vs citrate
Sources
- NHS. Vitamins and minerals: others (magnesium). Last reviewed August 3, 2020; read October 15, 2026.
- Expert Group on Vitamins and Minerals. Safe Upper Levels for Vitamins and Minerals. Food Standards Agency, 2003 (archived copy; the FSA link no longer works).
- EFSA. Scientific Opinion on Dietary Reference Values for magnesium. EFSA Journal 2015;13(7):4186.
- EFSA / Scientific Committee on Food. Tolerable Upper Intake Levels for Vitamins and Minerals (magnesium, 2001), 2006; still the current figure in EFSA’s 2025 summary.
- Regulation (EU) No 1169/2011, Annex XIII, as retained in Great Britain: nutrient reference values (magnesium 375 mg).
- US NIH Office of Dietary Supplements. Magnesium fact sheet for health professionals.
- Mah J, Pitre T. Oral magnesium supplementation for insomnia in older adults. 2021. PubMed 33865376. Schuster J, et al. Magnesium bisglycinate in adults reporting poor sleep. 2025. PubMed 40918053.
- Products: Amazon.co.uk listings and Solgar and Lamberts UK websites, read October 15, 2026.