Vitamin B1 (Thiamine) forms for supplement manufacturing

How the vitamin B1 forms compare

The two vitamin B1 forms on this page are thiamine hydrochloride and thiamine mononitrate. Calculated from their formulas, they contain 78.7 % and 81.1 % thiamine respectively, anhydrous basis. The best form of vitamin B1 for a product depends more on format than on content. The hydrochloride suits liquids and soluble formats. The mononitrate suits dry blends and tablets.

The content figures divide the molar mass of the thiamine cation (C12H17N4OS+, 265.36 g/mol) by the molar mass of each salt: 337.3 g/mol for the hydrochloride and 327.36 g/mol for the mononitrate. Commercial lots are tested against a specification, and the certificate of analysis states the assay and its basis. Use those figures for batch calculations, or run them through the elemental content calculator.

As a worked example, a label claim of 10 mg thiamine per serving needs about 12.7 mg of thiamine hydrochloride or 12.3 mg of thiamine mononitrate. A claim of 50 mg needs about 63.6 mg or 61.7 mg. At these masses the content difference rarely decides capsule size or tablet weight.

The practical differences lie in solubility and moisture behaviour. Thiamine hydrochloride dissolves readily and gives acidic solutions, where thiamine is comparatively stable. It is also more hygroscopic, which can cause caking or loss in humid dry blends. Thiamine mononitrate is less hygroscopic and is the conventional choice for compressed multivitamin tablets and long-shelf-life premixes.

Both forms share the same weaknesses. Thiamine degrades with heat, in neutral to alkaline conditions and in the presence of sulfites. Both have a characteristic bitter, slightly sulfurous taste and odour, noticeable in chewables, gummies and unflavoured powders.

Cobalamin forms are covered separately in the vitamin B12 forms guide.

Choosing a form

• Format. For drinks, liquid concentrates and effervescent tablets, the hydrochloride dissolves fully and quickly. For tablets and dry premixes, the mononitrate handles humidity better during blending, compression and storage.
• Label basis. Confirm whether a claim or customer specification is expressed as thiamine or as thiamine hydrochloride. The two bases differ by about 27 %, a common source of under- or over-dosed batches.
• Switching forms. 1 g of thiamine mononitrate supplies the same thiamine as about 1.03 g of thiamine hydrochloride. Recheck stability and dissolution after any switch, not only the input mass.
• Stability and overage. Losses over shelf life depend on moisture, pH, heat and the other ingredients in the formula. Set the overage from your own stability data; the overage calculator handles the arithmetic.
• Compatibility. Keep sulfite-containing ingredients and alkaline components away from thiamine where possible. In multi-nutrient blends, consider moisture from hygroscopic salts and the pH of any liquid phase.
• Taste. At typical inclusion levels in capsules taste is irrelevant. In chewables, gummies and powders, budget for flavour masking whichever form you choose.
• Cost. Compare offers per kilogram of thiamine, not per kilogram of salt, so that the content difference is accounted for.
• Regulatory status. Both forms are listed for use in EU food supplements, so the choice is technical rather than regulatory.

When you request a quote through the quote form, state the form, the label basis and the dosage format.

EU regulatory status

Directive 2002/46/EC governs vitamins and minerals in food supplements. Annex I lists thiamin among the vitamins that may be used. Annex II lists thiamin hydrochloride and thiamin mononitrate as permitted forms. The permitted forms guide explains how the two annexes work together.

The Directive also requires permitted forms to meet purity criteria. Where Union specifications do not exist, generally acceptable purity criteria recommended by international bodies apply. The specification sheet shows which criteria a lot is tested against.

For foods other than supplements, Regulation (EC) No 1925/2006 contains its own Annex II list of vitamin forms. Both thiamine salts appear there too.

No harmonised EU maximum levels for thiamin in food supplements have been adopted. Member states apply national limits, and these differ. The competent authority of each member state publishes its rules; the maximum levels guide explains how to find them.

The label declares the amount of thiamin per recommended daily portion, together with a percentage of the reference value. The labelling guide covers the format. Authorised claim wording is held in the EU Register of nutrition and health claims, explained in the health claims guide.