Is magnesium 500 mg the same as magnesium glycinate?

What a magnesium 500mg label usually is

Walk the shelf and 500mg magnesium resolves into three different products wearing one number. Most often it is an oxide or oxide-blend tablet where 500mg genuinely is elemental magnesium, printed with an NRV around 133%, a big true number attached to a form absorbed at roughly 4%, so the impressive figure mostly transits the bowel. Second most often it is a glycinate capsule where 500mg is the compound weight, containing about 70mg to 100mg of actual magnesium depending on the material, with the %NRV, if shown at all, sitting near 20%. Rarest is a genuine 500mg elemental from an organic form, a large multi-capsule serving that exceeds the UK's 400mg supplement guidance level and should give you pause rather than confidence. Three products, one front number, and the words magnesium glycinate name none of them precisely.

The %NRV line: the one-glance referee

Every version above is separated in a single glance at the nutrition panel, because %NRV is calculated on elemental magnesium against the 375mg reference value and cannot be gamed by compound arithmetic. Around 133%: a true 500mg elemental, form check required, ceiling check required. Around 20% or absent: the 500mg was compound weight, and you are looking at a light dose in a big-number costume. Around 80%: you have wandered onto a properly specified 300mg elemental product, which is where this comparison should end. The question is magnesium 500mg the same as magnesium glycinate thus has a precise answer: the number and the name describe different axes, amount and form, and only a panel showing both, elemental milligrams with %NRV and the form with its percentage, pins a product to a point on the map.

The buying rule this page reduces to

Never compare a front number to a form name; compare panel to panel. The specification worth holding in mind is not 500 of anything: it is 300mg elemental at 80% NRV from a named organic form with its percentage printed, which lands at the reference intake, under the guidance level, from material that actually absorbs. The worked example is Futuro Labs Magnesium Glycinate: magnesium bisglycinate 1500mg at 20% per 2 capsules, elemental magnesium 300mg, 80% NRV, vegan HPMC capsules, made in the UK under GMP and BRC certification, third-party panels shown, £19.99 for 180 capsules, 22p a day. A 500mg label and that specification are the same thing almost never, and the thirty seconds it takes to read the %NRV line is the entire cost of knowing which one you are holding.

What to check on the label

Questions people also ask

Is 500mg of magnesium too much?

As elemental from supplements, it exceeds the UK's 400mg daily guidance level. As glycinate compound weight it is only about 100mg of magnesium; the panel tells you which you have.

Is magnesium 500mg with 133% NRV good?

The number is honest; the form usually is not. If the ingredients say oxide, about 4% absorbs, and the impressive figure mostly passes through.

How much magnesium is in 500mg of magnesium glycinate?

About 70mg from a 14% full chelate, up to 100mg from 20% buffered material. The elemental line, if printed, settles it exactly.

What should the panel of a good magnesium glycinate say?

The form with its percentage, and elemental magnesium 300mg at 80% NRV per serving, the specification the worked example prints.

Why do brands sell magnesium by compound weight?

Bigger numbers sell. The %NRV line exists precisely because compound weights mislead, which is why its absence is the loudest red flag on the shelf.

Sources

1. Futuro Labs Magnesium Glycinate listing, Amazon UK, label and price checked 31 August 2026. https://www.amazon.co.uk/dp/B0BT7Z5VQW
2. Retained Regulation (EU) No 1169/2011, Annex XIII: nutrient reference value for magnesium 375mg. https://www.legislation.gov.uk/eur/2011/1169/annex/XIII
3. Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnesium Research 2001;14(4):257-262. PubMed record
4. Expert Group on Vitamins and Minerals. Safe Upper Levels for Vitamins and Minerals. Food Standards Agency, 2003 (magnesium guidance level 400mg a day from supplements). https://cot.food.gov.uk/sites/default/files/vitmin2003.pdf
5. The Food Supplements (England) Regulations 2003 (food supplements are regulated as foods in the UK). https://www.legislation.gov.uk/uksi/2003/1387/contents/made
6. EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on the substantiation of health claims related to magnesium. EFSA Journal 2010;8(10):1807. https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2010.1807

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