Folic Acid (Vitamin B9)

Grades and forms

Folic acid (pteroylmonoglutamic acid) is the synthetic, fully oxidised form of folate used in most EU food supplements. It is an orange to yellow crystalline powder, and labels declare it in micrograms. Because a serving holds only micrograms of folic acid, the choice of grade is mostly a choice about how you will dilute it. The folate nutrient guide covers the wider family of forms.

Manufacturers buy two broad types of folic acid powder:

• Pure crystalline folic acid: food grade or pharmacopoeia grade. It suits plants that make their own premix or add folic acid to a multi-vitamin premix.
• Diluted forms (triturations): folic acid dispersed on a carrier at a stated content. They make weighing and blending microgram quantities practical in standard equipment.

Four points usually decide the choice:

• the pharmacopoeia your customers or markets require
• whether you have a validated premixing step
• the carrier’s compatibility with the rest of the formula
• the assay basis stated on the certificate

Ask for the grade you need in the quote form. SoleChem sends the specification sheet and the certificate of analysis with its quote.

EU regulatory status

The vitamin is listed in Annex I of Directive 2002/46/EC. Pteroylmonoglutamic acid, which is folic acid, is listed under folate in Annex II. Folic acid may therefore be used as a vitamin source in food supplements throughout the EU. The permitted forms guide explains how the two annexes work together.

The same substance appears in Annex II of Regulation (EC) No 1925/2006, which covers adding vitamins to other foods. Maximum amounts in food supplements are not harmonised at EU level. Each member state sets its own, as described in the maximum levels guide.

The label declares the amount in the unit given in Annex I of the Directive, which for this vitamin is micrograms. The percentage declaration uses the reference value in Annex XIII of Regulation (EU) No 1169/2011. See the labelling guide for the full requirements. For authorised claim wording, consult the EU Register of nutrition and health claims and the health-claims guide.

Formulation notes

Content uniformity. Microgram inclusion is the main technical risk. Use geometric dilution or a pre-blend with a carrier before adding folic acid to the main batch. Validate blend uniformity, and watch for segregation in direct-compression tablets where particle sizes differ widely.

Solubility. Folic acid dissolves poorly in water and in acidic solutions. It dissolves in dilute alkaline solutions. This matters for liquids, drink powders and effervescent tablets, where the matrix is usually acidic.

Light and heat. Folic acid degrades under light, especially ultraviolet. In solution, riboflavin speeds up this photodegradation. Protect premixes during processing and use light-protective packaging. Losses are greater in solution, at low pH and with heat.

Overage. Set any overage from your own stability data for the finished product. The overage calculator handles the arithmetic.

Label-claim arithmetic. Label claims are expressed as folic acid. Calculate the input per serving like this:

• input (µg) = label claim (µg) ÷ folic acid content as a decimal fraction
• for a trituration, use the folic acid content stated on its certificate
• if the assay is on the anhydrous basis, first multiply it by (1 − water fraction) to get the as-is content

The certificate of analysis states which basis applies to each lot.

How it compares to other forms

The two forms have different molar masses, so the same mass of powder does not deliver the same amount of folate. Agree the expression basis with your regulatory team before setting the label claim. The folic acid vs L-methylfolate comparison works through the differences.