Vitamin B2 (Riboflavin) forms for supplement manufacturing

How the forms compare

There is no single best form of vitamin B2 for manufacturing. The choice is between riboflavin, which is the vitamin itself, and riboflavin 5’-phosphate sodium, which supplies about 78.7 % riboflavin by mass. Riboflavin suits dry formats. The phosphate salt is the water-soluble form for drinks, effervescent tablets and other aqueous systems.

The content figure drives the weighing. To declare 10 mg of riboflavin per serving you need 10 mg of riboflavin or about 12.7 mg of riboflavin 5’-phosphate sodium. Both figures are before correction for the assay on the certificate of analysis and before any overage. The elemental content calculator and the overage calculator handle both steps.

Solubility decides how each form behaves in water. Riboflavin stays largely undissolved in a liquid, so it can settle or show as yellow specks. Riboflavin 5’-phosphate sodium dissolves to give a clear yellow solution with a green fluorescence.

Both forms are intensely yellow and both are sensitive to light, particularly in solution. Even at milligram inclusion levels they colour a tablet or powder visibly, so blend uniformity shows up as colour uniformity. Opaque packaging and opaque capsule shells limit light exposure during storage.

Choosing a form: best form of vitamin B2 by format

• Format. For tablets and capsules, riboflavin is the usual choice because solubility is irrelevant there. For effervescent tablets, drink powders and liquids, the phosphate salt dissolves fully. For gummies, the phosphate salt dissolves in the aqueous mass, while riboflavin can only be dispersed.
• Label claim per capsule. Vitamin B2 claims are usually expressed in milligrams, so the 21 % difference in content rarely limits fill volume. It matters more for blend uniformity, because such small masses need a premix or a diluted form to distribute evenly.
• Appearance. Riboflavin can cause yellow speckling in tablets if it is poorly dispersed. In clear drinks, undissolved riboflavin gives sediment; the phosphate salt does not.
• Taste. Both forms have a bitter note. In chewables, gummies and drinks, plan flavour masking around the vitamin B2 content.
• Cost per milligram of riboflavin. Riboflavin generally costs less per milligram of the vitamin. The phosphate salt usually costs more per kilogram and delivers less riboflavin per gram.
• Regulatory status. Both forms are listed for use in food supplements, so the choice is technical rather than regulatory.

Riboflavin 5’-phosphate is the compound known as flavin mononucleotide (FMN). That is a chemical description. Any product wording suggesting one form works better in the body is a health claim and falls under Regulation (EC) No 1924/2006; see the health-claims guide before writing it.

Combining both forms is uncommon. It can make sense in a range that shares one vitamin premix across tablets and drinks, provided each product’s label claim is calculated on the actual form used. Name the form and format in the quote form; SoleChem sends the specification sheet and the certificate of analysis with its quote.

EU regulatory status

Directive 2002/46/EC lists vitamin B2 in Annex I. Annex II lists both riboflavin and riboflavin 5’-phosphate, sodium, as substances that may be used to manufacture food supplements. The site’s guide to permitted forms covers the Annexes in more detail.

Article 4 of the Directive also sets out which purity criteria apply to the substances in Annex II. Where EU purity criteria exist for the same substance as a food additive, they are found in Regulation (EU) No 231/2012. The specification sheet states the grade and the standard the material meets.

The EU has not set harmonised maximum levels for vitamin B2 in food supplements. Member states apply their own rules, which differ, and some require notification when a product is placed on their market. The guide to maximum levels by country explains how these national rules work.

Riboflavins are also authorised food colours under Regulation (EC) No 1333/2008. When either form is added as a source of vitamin B2, the food-supplement rules apply. When it is added to colour the product, the additive rules and their conditions of use for food supplements apply.

On the label, vitamin B2 is declared as the vitamin in milligrams, not as the mass of the salt. The labelling guide covers the declaration format under Directive 2002/46/EC and the general labelling rules of Regulation (EU) No 1169/2011.