Magnesium forms for supplement manufacturing

How the magnesium forms compare

The magnesium forms SoleChem supplies range from 8.9 % to 60.3 % elemental magnesium, anhydrous basis. That spread sets how much raw material a label claim needs: 166 mg of magnesium oxide or 1,121 mg of magnesium taurate per 100 mg of magnesium. The table compares the forms as manufacturing materials, not on physiological effect.

Oxide and carbonate are inorganic and carry the most magnesium per gram. Both are practically insoluble in water but react with acids. Carbonate releases carbon dioxide on contact with acid, which is why it pairs with food acids in effervescent systems. Neither suits a clear ready-to-drink liquid.

The citrate, malate, bisglycinate and taurate forms combine magnesium with an organic acid or an amino acid. The counter-ion adds mass, so content falls to between 8.9 % and 16.2 %. Magnesium taurate, the salt of magnesium with taurine, sits at the bottom of that range. Solubility depends on stoichiometry, hydration and grade, so the specification sheet is the reference.

All percentages above are theoretical values on the anhydrous basis. Commercial grades are often hydrates, and some bisglycinate grades are buffered with magnesium oxide. Use the assay on the certificate of analysis for label-claim arithmetic; SoleChem sends the specification with every quote. The elemental content calculator and overage calculator handle the recalculation.

Choosing a form

There is no single best form of magnesium for manufacturing. The choice follows the label claim, the format, the cost target and the regulatory position in each market.

• Label claim per unit. A claim of 200 mg magnesium needs about 332 mg of oxide, 694 mg of carbonate, 1,238 mg of citrate, 1,286 mg of malate, 1,418 mg of bisglycinate or 2,242 mg of taurate. High claims in one unit point to oxide or carbonate. The organic forms usually need more than one capsule or tablet per serving.
• Format. Oxide and carbonate keep tablet mass low; see ingredients for tablets. Capsule fill volume limits the organic forms; see ingredients for capsules. Carbonate works as a reactive base and trimagnesium dicitrate as a soluble salt in effervescent tablets. Citrate forms are common in drink powders and sachets. In gummies the mass a piece can carry is the constraint.
• Solubility. Clear drinks and effervescent tablets need a form that dissolves. Capsules and tablets tolerate insoluble forms.
• Taste. Magnesium salts can taste bitter or astringent in solution. Masking matters most in drinks, chewables and gummies.
• Cost per milligram of magnesium. Oxide and carbonate are generally the lowest. Organic salts and chelates cost more per milligram, and taurate’s 8.9 % content makes it the most expensive per milligram of magnesium.
• Regulatory status. The form must be permitted for food supplements in the EU and in each target market. See the section below.

Magnesium citrate vs glycinate

Citrate carries 16.2 % magnesium against 14.1 % for bisglycinate. Per 100 mg of magnesium that means about 619 mg of citrate or 709 mg of bisglycinate. Citrate is the usual choice for drink powders and effervescent formats, while bisglycinate is used mostly in capsules and tablets. The magnesium citrate vs magnesium glycinate comparison covers both in detail.

Magnesium oxide vs citrate

Oxide needs 166 mg of powder per 100 mg of magnesium; citrate needs 619 mg, close to four times as much. Oxide suits compact tablets and low cost per milligram. Citrate suits products that must dissolve. See magnesium oxide vs magnesium citrate.

EU regulatory status

Article 4(1) of Directive 2002/46/EC permits only the vitamins and minerals in Annex I, in the forms in Annex II, in food supplements. Magnesium is in Annex I. Annex II lists magnesium carbonate, magnesium oxide, magnesium salts of citric acid and magnesium bisglycinate.

Magnesium citrate and trimagnesium dicitrate both fall under the citric acid salts entry. Magnesium malate and magnesium taurate are also listed in Annex II under their own entries. The permitted forms guide explains how to read the list. For fortified foods, the parallel list is in Annex II of Regulation (EC) No 1925/2006.

Magnesium carbonate (E504) and magnesium oxide (E530) are also food additives under Regulation (EC) No 1333/2008. Additive use follows that regulation; use as a magnesium source follows the supplement rules. Specifications for food additives, including purity criteria, are set in Regulation (EU) No 231/2012; check the entries for E504 and E530.

Maximum amounts of magnesium per daily portion are not harmonised at EU level. Article 5 of the directive provides for them, but member states currently set their own. Some member states also require notification of the placing on the market, with a model of the label. See maximum levels by EU country.

Article 8 of the directive requires the amount of each nutrient to be declared per recommended daily portion. For magnesium that is milligrams of the element, not of the salt; see labelling a food supplement. Authorised claim wording is in the EU Register of nutrition and health claims, explained in the health claims guide.