An official control laboratory finds 19 µg of vitamin D in a sample declared at 25 µg per daily portion (hypothetical example). Is that non-compliant? The answer depends on the tolerance range. The European Commission guidance of December 2012 on tolerances sets −20% to +50% for vitamins in food supplements and −20% to +45% for minerals around the declared value. These tolerances already include measurement uncertainty, so the authority does not add it a second time. The limits are calculated from the extreme values that round to the number on the label, and the result must stay within the range throughout the shelf life. Where the declaration sits exactly at a claim threshold (“source of”, a health-claim condition), only measurement uncertainty is tolerated downwards. In the example above the lower limit is 19.6 µg, so 19 µg is outside the tolerance and is assessed under the criteria in point 2.4 of the guidance.
1. Legal status: the law says “average values”, the guidance gives the numbers
Article 8(2) of Directive 2002/46/EC requires vitamins and minerals to be declared per portion of the product as recommended for daily consumption. Article 9(1) adds that the declared values “shall be average values based on the manufacturer’s analysis of the product”. Polish law repeats this in § 5(6) of the Minister of Health regulation: contents are expressed as average values based on the manufacturer’s analysis of the product.
Neither the Directive nor the national regulation sets a percentage tolerance. Article 9(1) of the Directive provides for further rules on differences between declared values and those established in official checks to be decided in committee procedure. The figures authorities actually use come from the Commission guidance of December 2012, agreed with the Member States. The document itself states that it has no formal legal status and that ultimate interpretation lies with the CJEU. In control practice it is nevertheless the reference point, and the guidance expressly asks authorities to account for these tolerances in their control plans.
2. Table 2 of the guidance: tolerances for food supplements
| Nutrient | Food supplements (Table 2) | Other foods (Table 1), for comparison |
|---|---|---|
| Vitamins | +50% / −20% | +50% / −35% |
| Minerals | +45% / −20% | +45% / −35% |
The narrower lower limit for supplements (−20% instead of −35%) reflects that a supplement is a dosed form and its nutrient content is its main parameter. The upper limit is wide because manufacturers use an overage to compensate for vitamin degradation during storage. For vitamin C in liquids the guidance accepts higher upper tolerances, without giving a figure. Table 2 tolerances “include the uncertainty of measurement”. The authority therefore may not widen the range by the laboratory’s uncertainty, and the operator may not subtract it from a result below the limit.
3. How to calculate the range: rounding first, then the percentage
The guidance applies the tolerance to the extreme values that round to the number on the label (section 6). Vitamin A, folic acid, chloride, calcium, phosphorus, magnesium, iodine and potassium are rounded to 3 significant figures; all other vitamins and minerals to 2. The guidance’s own example: folic acid declared at 125 µg per unit corresponds to 124.5–125.4 µg, so the tolerance range is 99.6–188 µg.
| Declaration per daily portion (example) | Values behind the rounding | Lower limit | Upper limit |
|---|---|---|---|
| Vitamin D 25 µg (2 significant figures), no claim | 24.5–25.4 µg | 24.5 × 0.80 = 19.6 µg | 25.4 × 1.50 = 38.1 → 38 µg |
| Magnesium 300 mg (3 significant figures), no claim | 299.5–300.4 mg | 299.5 × 0.80 = 239.6 → 240 mg | 300.4 × 1.45 = 435.6 → 436 mg |
| Folic acid 125 µg (guidance example 2) | 124.5–125.4 µg | 99.6 µg | 188 µg |
4. Declaration at a claim threshold: only measurement uncertainty downwards
Table 2 is not the only rule. Section 5 of the guidance covers nutrients for which a nutrition or health claim under Regulation 1924/2006 is made. The guidance expressly mentions the vitamin or mineral level for a “source of” claim and the levels in the conditions of use of health claims. The vitamin and mineral health claims in Regulation 432/2012 require the product to be at least a “source of” the nutrient, i.e. 15% NRV per daily portion. Three situations follow:
- Point 5.1 – declaration equal to the threshold. Example: zinc 1.5 mg (15% of the 10 mg NRV) with a zinc health claim. Below the declaration only measurement uncertainty is tolerated; above it, the “side 1” tolerance of Table 3 (+45% for minerals, +50% for vitamins). A 1.5 mg declaration corresponds to 1.45–1.54 mg. A result of 1.30 mg ± 0.13 mg (10% uncertainty assumed) gives 1.43 mg and is outside the tolerance. A result of 1.35 mg ± 0.14 mg gives 1.49 mg and is within it.
- Point 5.2 – declaration with a safe margin. If the Table 2 lower limit does not reach the claim threshold, the ordinary −20%/+45% applies. Zinc 2.0 mg corresponds to 1.95–2.04 mg, and 1.95 × 0.80 = 1.56 → 1.6 mg, above 1.5 mg. The range is 1.6–3.1 mg.
- Point 5.3 – the intermediate zone. If the Table 2 range overlaps the threshold (e.g. zinc 1.8 mg: 1.75 × 0.80 = 1.40 mg < 1.5 mg), the guidance applies a tolerance of the “side 1” magnitude of Table 3 to the level in the claim conditions, not to the declaration. The claim threshold itself therefore remains the lower limit.
Point 5.4 adds that where the claim states a specific figure above the threshold (“contains 3 mg zinc”), point 5.1 applies to that figure. Practical conclusion: a product bearing a claim cannot “use” the −20% if its declaration sits at the threshold.
5. The Polish 15% NRV minimum and the tolerance
§ 4(2) of the Polish Minister of Health regulation requires every vitamin and mineral to be present in the recommended daily portion at no less than 15% of the NRV in Annex XIII Part A point 1 FIC. This is a composition requirement, not a claim. Section 5 of the 2012 guidance covers the minimum amounts under Regulation 1925/2006 for fortified foods, but does not mention national minima for supplements. There is thus no text allowing a product to fall below 15% NRV at control by virtue of the −20% tolerance. A declaration exactly at 15% NRV is the most exposed: any result below the declaration that measurement uncertainty does not explain can be challenged both as a deviation from the declaration and as a failure to meet the composition minimum.
6. Upper limit and maximum amounts
The guidance states (point 2.1 and section 5) that where maximum amounts of vitamins or minerals have been set, the maximum takes priority over the upper tolerance. A +50% tolerance does not legalise exceeding a maximum. Article 5 of Directive 2002/46/EC provides for maximum and minimum amounts to be set by the Commission. In the absence of harmonised rules, Member States may apply national rules compatible with Articles 34 and 36 TFEU, and the guidance leaves existing authority practice in place in that case. For formulation, this means the stability overage must be planned so that the top of the range does not exceed the level the target market treats as the maximum.
7. The whole shelf life, and what happens when a result falls outside the range
Point 2.2 of the guidance: the measured value should be within the tolerances during the entire shelf life. For vitamins prone to degradation, such as vitamin C, the declaration must take into account the stability result at the end of shelf life, not only the analysis of a fresh batch. Point 2.3 adds that declared values should approximate the average across multiple batches and should not be set at either extreme of the range. For nutrients consumers want more of, the declaration must not exceed the actual average.
A result outside the tolerance does not automatically mean a sanction. Point 2.4 of the guidance lists factors the authority should assess: the nutrient, the extent and direction of the deviation, natural variation, degradation rates in the matrix, analytical variability, product homogeneity, results of other samples from the lot, the validity of the manufacturer’s process for establishing the declaration, how the company’s self-monitoring works, and previous problems or sanctions. The response depends on these: from guidance and warnings to enforcement notices or fines. The manufacturer may be asked to justify the deviation.
For samples taken in official controls, Article 35 of Regulation (EU) 2017/625 gives the operator the right to a second expert opinion at its own expense. It is therefore worth knowing the method and uncertainty of the laboratory that tested the sample, and having your own batch and stability data ready before responding to the authority.
8. What the guidance does not decide
- Other substances (botanical extracts, caffeine, lutein, omega-3 fatty acids, probiotics). Table 2 covers only vitamins and minerals. For other substances declared under Article 8(1) of the Directive there are no numerical EU tolerances. Assessment rests on Article 9(1) of the Directive (average values from analysis) and the prohibition on misleading information in Article 7 FIC.
- Permissibility of the chemical form. The tolerance concerns quantity, not whether a form may be used in a supplement.
- The %NRV figure on the label. The %NRV (Article 8(3) of the Directive) follows from the declared amount; there is no separate tolerance for the percentage.
- Foods for specific groups. The guidance does not cover foods under Directive 2009/39/EC (foods for particular nutritional uses, which then included FSMP) or mandatory fortification under Article 11 of Regulation 1925/2006.
9. Checklist: declaring vitamins and minerals on a food supplement
- Analyse the finished product. Base the declaration on analysis of the product (Article 9(1) of the Directive, § 5(6) of the Polish regulation), ideally across several batches.
- Stability. Set the overage from stability testing so that at the end of shelf life the result does not fall below −20% of the declaration.
- Range. Calculate the limits from the values behind the rounding (2 or 3 significant figures) and compare them with batch results.
- Claims. If the product bears a “source of”, “high” or 432/2012 health claim, check whether the declaration sits at the threshold (points 5.1/5.3). If so, you have only measurement uncertainty downwards.
- 15% NRV minimum. On the Polish market, do not declare a nutrient exactly at the § 4(2) minimum without an analytical margin.
- Maxima. Check that the top of the range (+50% / +45%) does not exceed the maximum applied in the target market.
- Documentation for inspection. Keep the specification, batch results, stability report and overage rationale together, ready to present to the authority.
Glossary
- Tolerance
- The acceptable difference between the declared value and the value established in official control (section 1.1 of the 2012 guidance).
- Measurement uncertainty
- A parameter of the laboratory result determined for each analysed value; already included in the Table 2 tolerance.
- Overage
- Deliberately adding more of a nutrient than declared so that content does not fall below the tolerance by the end of shelf life.
- Side 1 / side 2
- Columns of Table 3 of the guidance: a quantitative tolerance on one side, only measurement uncertainty on the other.
Conclusion
A vitamin in a food supplement may deviate from its declaration by −20% to +50%, a mineral by −20% to +45%, calculated from the values behind the rounding and with measurement uncertainty already included. This rule comes from Commission guidance, not from legislation, but control authorities use it as the reference point. It has two important limits. First, a declaration at a claim threshold removes the downward margin: only measurement uncertainty remains. Second, the range must hold until the last day of shelf life, and its top may not exceed a maximum. A safe declaration rests on analysis of the finished product, stability testing and a deliberately planned overage.
Primary sources
- European Commission, Guidance document for competent authorities … with regard to the setting of tolerances for nutrient values declared on a label (December 2012): points 2.1–2.4, section 4 (Table 2), section 5 (Table 3, points 5.1–5.4), section 6.
- Directive 2002/46/EC on food supplements: Articles 5, 8, 9.
- Polish Minister of Health Regulation on the composition and labelling of food supplements (consolidated text Dz.U. 2023 item 79): § 4(2), § 5(3)–(6).
- Regulation (EU) No 1169/2011: Articles 7, 29(1)(a), 31(4); Annex XIII Part A.
- Regulation (EC) No 1924/2006: Annex (“source of”, “high” claims).
- Commission Regulation (EU) No 432/2012: conditions of use for vitamin and mineral health claims.
- Regulation (EU) 2017/625 on official controls: Article 35 (second expert opinion).
Related: “Source of vitamin” on a food supplement: which portion 15% NRV refers to.