Magnesium glycinate: what the label has to tell you

Two weights, not one

Magnesium glycinate is a compound. The magnesium sits bound to glycine, so the weight of the compound and the weight of the magnesium inside it are two different numbers.

Read the compound weight as the weight of the raw material used. Read the elemental figure as the magnesium itself. Mixing them up is the most common misreading of this kind of label.

Where the elemental figure lives

On a UK supplement label the nutrient panel names the nutrient and gives the amount per stated portion. That amount refers to elemental magnesium, not to the glycinate it arrived in.

The ingredients list is where the compound name appears. Seeing magnesium bisglycinate in the ingredients and magnesium in the nutrient panel is normal, and the two figures are not meant to match.

• Nutrient panel row: magnesium, as elemental magnesium per portion.
• Ingredients list: the salt or chelate the magnesium was supplied as.
• A large front of pack number with no panel behind it is pack design, not label data.

What the NRV percentage is actually doing

NRV stands for nutrient reference value. It is a fixed reference figure per nutrient, set in law, and the percentage simply states how the portion compares with that reference.

It is a comparison column and nothing else. Two labels showing the same magnesium NRV percentage carry the same elemental magnesium per portion, whatever compound is printed on the front.

Ninety capsules is not ninety portions

This pack is listed as 90 capsules. That is a count of capsules and carries no information about how long a pack lasts.

A portion may be one capsule or several, and only the label can say which. Until the portion is stated, two packs with the same capsule count are not comparable on cost.

Lining this up against other magnesium formats

Magnesium compounds carry different proportions of elemental magnesium by weight, so identical milligram figures in two ingredients lists can resolve to very different nutrient panel rows.

• Read the nutrient panel first, then go back to the ingredients list.
• Compare elemental magnesium per portion, never capsule size or capsule count.
• Work out cost per portion only once the portion size is printed.

What the label tells you

The full ingredients list, the amount per portion, allergens, dietary suitability, directions and storage are printed on the pack.

Read the label before you take any supplement, and check the product page for the format, pack size and price before you buy.