Abbreviations on magnesium, zinc and iron packaging

Magnesium cannot be put into a capsule in its pure form — it is a metal. In supplements it appears as a salt or chelate, meaning combined with something else: citric acid, oxygen or glycine. That “something else” also has mass, usually much more than magnesium itself.

That is why “Magnesium citrate 1000 mg” and “Magnesium 1000 mg” are two entirely different statements. Regulations require the element itself to be stated in the nutrition table, so the number you need is always there — it just rarely appears on the front of the package.

The terms one by one

Elemental ionmagnesium, zinc or iron content

The mass of the element itself, without the rest of the molecule. It is the only value that can be compared fairly between products, and the only one we calculate. In the nutrition table it is simply described as “Magnesium”, “Zinc” or “Iron”.

Citratecitric acid salt

The most common form of magnesium. Magnesium itself accounts for about 16% of its mass, so 1000 mg of citrate contains roughly 160 mg. Manufacturers who promote a large number on the front almost always state the mass of the salt.

Magnesium oxidethe simplest magnesium salt

It contains about 60% magnesium, the most of all common forms. That is why products with a high elemental content in a small tablet are usually based on oxide.

Diglycinateamino-acid chelate

A combination of an element with two glycine molecules. The elemental content is low here, about 14% for magnesium, so tablets can be large or the dose divided into several units per day.

Lactatelactic acid salt

An intermediate form, about 12% magnesium. Common in pharmacy products combined with vitamin B6.

Picolinatepicolinic acid salt

The most common form of zinc in supplements. As with every salt, the number on the front describes the whole molecule — zinc itself is about 21% of its mass.

Zinc oxidethe simplest zinc salt

It contains about 80% zinc, the most of all forms found in supplements. This is why it appears in multi-ingredient products, where space in a tablet is limited.

Gluconategluconic acid salt

Found in both zinc and iron products. The elemental content is low: about 14% for zinc and about 12% for iron, several times less than in oxide.

Sulphate and fumarateiron salts

The two most common iron forms, with different elemental content: about 20% in heptahydrate sulphate and about 33% in fumarate. The label must still state iron itself in the table, so there is no need to calculate it independently.

B6vitamin B6 with magnesium

A standard addition to magnesium products. It changes the product composition, so we treat pure magnesium and magnesium with B6 as two different things.

Other groups of terms

Omega-3 Vitamin D Vitamin C B vitamins Collagen Creatine Probiotics Label and calculations

How the numbers from a label turn into the cost of a day is shown in the omega-3 calculator — for now this is the only finished category. The rules by which we build the ranking are described in the How we rank section.