Allergen Analysis: Reporting the 26 EU Allergens in Fragrance Products

A fragrance leaves a mark on skin. Sometimes a pleasant memory, sometimes a rash. The European Union took the latter seriously and placed certain fragrance substances on a mandatory disclosure list. The rest is your responsibility.

For many years this list was known as the 26 substances. The 2023 revision (EU 2023/1545) expanded it, pushing the total number of declarable substances above 80. So the term "26 allergens" now serves as shorthand for a larger family — yet the core group in industry parlance still consists of those original 26 names.

The critical point here is this: these substances are not "dangerous" — they are "declarable". They are ingredients that sensitive skin types need to be aware of, but which can be used safely at the correct levels. Being on the list is not a ban; it is a demand for transparency.

The correct approach, therefore, is to know which allergen is present at which level when you formulate your fragrance oil. You cannot put on a label what you do not know; and what you omit from the label creates legal risk.

Your nose may sense a Citral, but it cannot tell you its proportion. The eyes of this operation are GC-MS: Gas Chromatography–Mass Spectrometry (gas chromatography separates the substance; the mass spectrometer identifies each component).

The working principle is straightforward: a fragrance oil sample is vaporised and separated into molecules that travel at different speeds along a column (a long, narrow tube). Each molecule leaves the column at a different time — this is called the retention time. The mass spectrometer then provides the "fingerprint" of each component. Together, they reveal every allergen in your fragrance oil, both by identity and by proportion.

This follows the same logic as other methods used to characterise a fragrance oil: a refractometer reads the refractive index; a viscometer describes flow. GC-MS is the chemical map of the composition. All three together form the quality profile of a fragrance oil.

Do not confuse two separate concepts. One is the usage limit (IFRA — how much of a substance you may include); the other is the declaration threshold (SCCS/EU — above what level you must declare it on the label).

The declaration threshold under the classic rule is clear: for leave-on products (those that remain on skin, such as perfume), any allergen present above 0.001% (10 ppm) in the finished product must be named on the label; for rinse-off products (such as soap), the threshold is 0.01% (100 ppm). Allergens below these thresholds do not trigger a declaration requirement.

Important caveat: IFRA limits apply to individual substances within the fragrance oil and to the product category — not to the total fragrance oil proportion. There is no blanket rule such as "any fragrance oil is safe up to 20%." If a fragrance oil contains a high level of Citral, that substance may reach the IFRA ceiling even at a low fragrance oil dosage.

Finding the allergen percentage in the finished product is a simple chain calculation: allergen proportion in the fragrance oil × fragrance oil proportion in the formula = proportion in the finished product.

You have gathered the data and done the calculations. Now you need to transfer that information correctly — both to the label and to your B2B customers. The process follows a step-by-step sequence.

The pitfalls where manufacturers stumble in allergen reporting are well-known. Let's flag a few traps, then answer three fundamental questions.

The biggest mistake is taking the allergen percentage as it appears in the fragrance oil and writing it directly on the label. What goes on the label is the proportion in the finished product, not in the fragrance oil. The second mistake is calculating by ml and ignoring the density difference. The third is being stuck on the old "26 allergens" list and overlooking the 2023 expansion.