Fragrance allergens in perfumery: how to read a declaration and calculate them in the finished product

A raw material allergen declaration is one of the most useful documents when a fragrance formula needs to become a real cosmetic product. Yet this document is also frequently misread: someone sees, for example, “Limonene 25%” and assumes that the finished perfume contains 25% limonene, or confuses the presence of an allergen with an IFRA restriction.

The correct principle is different. The supplier declaration describes the presence of allergens in the raw material or commercial mixture. To determine what must be declared on the cosmetic label, you need to calculate how much of each allergen actually reaches the finished product, adding together all relevant sources.

In the European Union, individual fragrance-allergen labelling is governed by Annex III to Cosmetics Regulation (EC) No 1223/2009, as amended by Regulation (EU) 2023/1545.

What are the current labelling thresholds?

For fragrance allergens covered by Annex III, the individual name must appear in the ingredient list when its concentration in the cosmetic product exceeds:

• 0.001% in leave-on products;
• 0.01% in rinse-off products.

An alcoholic perfume intended to remain on the skin is a leave-on product. In fine fragrance, the practical reference threshold for individual allergen labelling is therefore normally 0.001% in the finished product.

Regulation (EU) 2023/1545 introduced individual labelling requirements for 56 additional fragrance allergens and updated several existing entries. From 31 July 2026, cosmetic products that do not comply with the new requirements can no longer be placed on the Union market. Products already placed on the market before that date may continue to be made available until 31 July 2028.

For current information, see also the European Commission page on fragrance allergen labelling.

What is a supplier allergen declaration?

The format is not identical across manufacturers. The document may be called an Allergen Declaration, Allergen Statement, EU Cosmetic Allergens, or something similar.

It usually contains a table with:

• the allergen name;
• CAS number or another identifier;
• percentage or concentration in the material;
• sometimes the regulatory reference or version of the allergen list used.

Always read the heading and notes carefully. A value may represent analytical data, a value calculated from composition, a maximum specification or another basis defined by the supplier. Do not automatically treat every number as the exact batch value if the document does not say that.

The fundamental calculation

If the raw material is used in a fragrance concentrate that is subsequently diluted to make the finished perfume, the complete calculation is:

% allergen in finished product = % raw material in fragrance concentrate × fraction of fragrance concentrate in finished product × fraction of allergen in raw material

Educational example:

• a raw material contains 25% Limonene;
• the raw material is used at 4% in the fragrance concentrate;
• the finished perfume contains 20% fragrance concentrate.

The calculation is:

4% × 0.20 × 0.25 = 0.20%

The Limonene contributed by that raw material is therefore present at 0.20% in the finished product. In a leave-on product, this is well above the 0.001% labelling threshold, so the relevant name required by the regulation must be considered in the ingredient list.

Calculating the raw material in the finished product first can be more intuitive

The same example can be calculated in two steps:

4% raw material in the concentrate × 20% concentrate = 0.8% raw material in the finished perfume.

Then:

0.8% × 25% allergen = 0.20% allergen in the finished product.

Both methods give the same result.

What if the raw material is already diluted?

You need to distinguish between the commercial concentration of the product and the allergen percentage stated in the supplier document.

If, for example, you buy a raw material already supplied at 50% in a solvent and the allergen declaration has been issued for that commercial product as supplied, the percentage stated in the document already refers to that commercial mixture. You should not arbitrarily “dilute it a second time”.

If instead you are using your own laboratory solution, for example at 10%, that laboratory dilution must also be included in the calculation.

Example:

• pure raw material containing 20% of an allergen;
• your laboratory solution is at 10%;
• you use 5% of that solution in the fragrance concentrate;
• the concentrate is used at 20% in the finished perfume.

Active raw material in the concentrate: 5% × 0.10 = 0.50%.

Allergen in the concentrate: 0.50% × 0.20 = 0.10%.

Allergen in the finished product: 0.10% × 0.20 = 0.020%.

Again, the final value is above the 0.001% threshold for a leave-on product.

The most important part: add all sources together

The same allergen can be present in many materials within one formula. Limonene, for example, may come from several natural raw materials and may also be present as a separate ingredient or as a component of a commercial base.

For finished-product labelling, the contribution from only one raw material is not enough: you must add all contributions of the same allergen.

None of the three sources, considered alone, exceeds 0.001%. The total does. In a leave-on product, the criterion therefore has to be assessed on the total concentration in the finished product, not ingredient by ingredient in isolation.

“Contains allergens” does not automatically mean “must appear on the label”

A raw material may contain traces or small amounts of a fragrance allergen. This does not automatically mean that the allergen name must appear in the finished product's ingredient list.

The correct question is: how much of that allergen is present in the finished cosmetic product?

If the total remains below the applicable threshold in Annex III, an individual declaration obligation does not arise for that specific reason. If the threshold is exceeded, the name required by the regulation must be considered in the ingredient list.

Allergen labelling and IFRA are two different checks

This distinction is essential.

An allergen can need to be listed on the label while the formula remains fully compliant with IFRA limits. Conversely, the fact that a material does not produce an allergen above the labelling threshold does not mean that it cannot have an IFRA restriction.

For maximum-use calculations in fine fragrance, see IFRA Category 4: how to read and calculate limits correctly.

An allergen and an H317 classification are not the same thing

Here too, the documents serve different purposes. H317 — May cause an allergic skin reaction is a CLP hazard statement found in the SDS. The requirement to list a fragrance allergen individually in a cosmetic product's ingredient list instead comes from the Cosmetics Regulation and Annex III.

You therefore cannot build the cosmetic allergen list by reading only Section 2 or Section 3 of an SDS.

For more on the purpose of that document, see SDS in perfumery: how to read a safety data sheet.

Natural raw materials require particular attention

Essential oils, absolutes, resinoids and other Natural Complex Substances can naturally contain several fragrance allergens. Their allergen profile can be much more complex than that of a single synthetic molecule.

When a formula contains several natural materials, the allergen calculation sheet must therefore collect contributions from all of them. It is not sufficient to write only the essential-oil name in the ingredient list and ignore constituents that must be declared individually when they exceed the applicable threshold.

It is also important to use documentation that corresponds to the material actually purchased: botanical origin, production method, grade and batch or commercial specification can affect the data supplied.

A fragrance base can contain allergens without revealing its complete formula

A commercial base or accord can have a proprietary composition. The supplier does not necessarily need to disclose the full formula in order to provide the data needed for regulatory calculation; it can supply an allergen declaration containing the relevant values for that mixture.

This is similar to the SDS: Section 3 does not necessarily represent the complete formula of a base. For allergen calculations, use the document specifically intended to communicate allergen data rather than trying to reconstruct the composition from the SDS alone.

Pay attention to names: a commercial name is not always the label name

The name appearing in a supplier's technical declaration may not be exactly the name that must be printed in the ingredient list. Regulation (EU) 2023/1545 updated several entries, including identifiers, isomers and, in some cases, groups of substances.

For labelling, you should therefore verify the current Annex III entry and the prescribed ingredient-list name rather than mechanically copying an old table or an outdated PDF.

Why 31 July 2026 matters

For many years, professionals worked mainly with the older group of fragrance allergens requiring individual declaration. Regulation (EU) 2023/1545 significantly expanded this system.

From 31 July 2026, the updated requirements apply to new cosmetic products placed on the EU market. Products that do not comply with the new requirements can no longer be placed on the market after that date. The period until 31 July 2028 concerns the continued availability of products that had already been placed on the market before 31 July 2026.

This means that a new formula being prepared today for future commercialisation should not be built using only an old “26 allergens” list found in teaching material or outdated documents.

Practical workflow for the formulator

1. Collect the current allergen declaration for every raw material, base or composition for which one is relevant.
2. Check which commercial product the document refers to and the basis on which the values are expressed.
3. Calculate the actual percentage of each raw material in the finished product.
4. Multiply by the percentage of the allergen in that raw material.
5. Add together the same allergen from every source.
6. Compare the total with the applicable threshold: 0.001% for leave-on or 0.01% for rinse-off, subject to any specific conditions in the relevant regulatory entry.
7. Verify the name to use in the ingredient list under the current Annex III.
8. Check IFRA, CPSR/PIF, SDS and other finished-product requirements separately.

An allergen calculation sheet is not a complete safety assessment

Allergen calculations are used, among other things, to determine which fragrance allergens must be individually identified in the ingredient list. They do not replace the Cosmetic Product Safety Report, the PIF, IFRA verification or the other checks required before commercialisation.

Likewise, exceeding an allergen-labelling threshold does not automatically mean that the product is “unsafe”. It means that consumers must be given the information required by law, particularly so that people who are already sensitised can identify substances of concern to them.

Conclusion

A supplier allergen declaration is not a list to copy onto the label. It is input data for a calculation.

For a professional formula, you need to move from the allergen concentration in each raw material to its actual concentration in the finished product and then add together all sources.

The decisive question is not “Does this raw material contain Limonene, Linalool or Citral?” but “How much of each allergen reaches the finished product in total, and does that total exceed the threshold requiring individual declaration?”

Technical note: the numerical examples are educational. For a product intended for commercialisation, use current supplier documentation, the current Annex III to Regulation (EC) No 1223/2009, the product safety assessment and all other applicable regulatory requirements.