Developing a fragrance involves much more than creating an appealing scent and finding the right balance between top, heart and base notes. Before a perfume can reach the market, a brand needs to understand precisely which substances are present in the composition, which are subject to restrictions, which allergens must be individually declared on the label, and how all of this affects the safety and formulation of the finished product.

Fragrance allergens play a particularly important role in this process. Many raw materials used in perfumery contain substances that can cause sensitisation reactions in certain individuals. This does not mean that an aromatic raw material is unsafe simply because it contains an allergen. It means that its use must comply with the relevant safety and regulatory framework and that, when certain thresholds are exceeded, specific substances must be individually identified in the ingredient list.

This issue is particularly relevant in the European Union. Commission Regulation (EU) 2023/1545 amended Regulation (EC) No 1223/2009 to expand the requirements for the individual labelling of fragrance allergens. The amendment followed, among other factors, the identification by the SCCS of 56 additional fragrance allergens that had caused allergies in humans and were not previously subject to the same individual labelling requirement.

For a fragrance brand, this means that allergen management should be addressed from the earliest stages of product development. It should not become a concern only when the packaging is ready to be printed. At MS PARFUMS, fragrance composition, raw-material documentation, final concentration, safety assessment and labelling should be understood as interconnected elements within the development of a perfume.

What are fragrance allergens?

Fragrances can contain dozens of different raw materials, each of which may itself have a complex chemical composition. Within these materials, certain substances are associated with the possibility of causing sensitisation or contact allergy in some individuals.

Once a person has become sensitised, subsequent exposure to a sufficient amount of the allergen may trigger a reaction. European regulation therefore addresses both the prevention of new sensitisation and the provision of information that allows consumers who are already sensitised to identify certain substances in the products they use.

This explains why individual allergen labelling is so important. A consumer who knows that they are sensitive to a particular substance needs to be able to determine whether that substance is present in a cosmetic product.

In perfumery, however, it is essential to avoid a common misunderstanding: “allergen” does not automatically mean “prohibited ingredient.” Depending on the substance, legislation may establish labelling requirements, concentration limits, restrictions on use or other specific conditions.

The technical challenge is therefore to know exactly which substances are present in the formula and determine which requirements apply to the finished product.

Allergens can come from both natural and synthetic raw materials

One of the most common misconceptions is that allergens are associated exclusively with synthetic ingredients. In reality, many substances subject to allergen declaration can occur naturally in essential oils, extracts and other aromatic raw materials of botanical origin.

This means that developing a fragrance positioned as natural does not automatically eliminate allergen considerations. The chemical composition of natural materials must be properly understood so that the presence of relevant substances in the finished product can be calculated.

Certain essential oils, for example, may naturally contain fragrance components covered by regulatory requirements. It is therefore not enough to look at the commercial name of the raw material. Its technical documentation and composition, together with the information supplied by the manufacturer or supplier, must be considered.

Synthetic ingredients are not exempt either. From a regulatory perspective, what matters is the presence of the relevant substances and the conditions applicable to them, rather than whether their origin is natural or synthetic.

This distinction is also important for marketing. Terms such as “natural” or “clean” should not be used to imply that a fragrance is automatically free from the possibility of sensitisation.

From the perfumer’s formula to the finished product

A brand may receive a fragrance composition developed by a perfumer and subsequently use it at a particular concentration to manufacture an Eau de Parfum, Eau de Toilette or another perfumed cosmetic product. However, managing allergens correctly requires more than simply knowing how much fragrance concentrate is being used.

It is necessary to determine which relevant allergens are present in that concentrate and what their effective concentration will be in the finished cosmetic product.

This calculation matters because European labelling requirements are based on the concentration of the relevant substances in the finished product.

For fragrance allergens subject to individual declaration, European legislation establishes thresholds of 0.001% in leave-on products and 0.01% in rinse-off products. When the applicable threshold is exceeded, the substance must be individually indicated in the ingredient list in accordance with the conditions established in Annex III of the Cosmetics Regulation.

A conventional hydroalcoholic perfume is generally a leave-on cosmetic product because it remains on the skin rather than being rinsed off. The relevant ingredients therefore need to be assessed according to the regulatory category and conditions applicable to the specific finished product.

This demonstrates why fragrance concentration can have technical and regulatory consequences. If the percentage of fragrance concentrate used in the finished formula changes, the final concentration of certain components may also change, potentially affecting the information that needs to appear on the label.

The European changes to fragrance allergen labelling

For many years, the European cosmetics industry worked with a defined group of fragrance allergens that had to be individually identified when their concentrations exceeded the relevant thresholds. Scientific assessment, however, continued to evolve.

The SCCS identified 56 additional fragrance allergens that had caused allergies in humans and were not previously subject to individual labelling. As a result, Regulation (EU) 2023/1545 expanded and updated Annex III of the EU Cosmetics Regulation.

The amendment is not simply a separate list of additional names. It also updates certain existing entries, groups some substances and specifies the names to be used in the ingredient list in particular circumstances.

For brands, this has a direct practical consequence: packaging artwork and ingredient lists must be prepared according to the regulatory requirements applicable when the product is placed on the market.

The regulation also introduced transitional periods to allow operators to adapt products and packaging. This makes it particularly important for fragrance projects being developed around the current transition period to use updated regulatory documentation rather than automatically reusing ingredient lists from older products.

A fragrance that was labelled correctly under previous requirements should therefore not simply be used as a template for a new launch without checking whether the applicable requirements have changed.

“Parfum” is not always enough in the ingredient list

On a cosmetic label, a fragrance composition may be identified using the term “Parfum.” However, this does not mean that every aromatic component can simply remain covered by that single designation.

Article 19 of the EU Cosmetics Regulation establishes requirements for ingredient information, while fragrance allergens subject to individual declaration under Annex III must additionally appear when their relevant thresholds are exceeded. Regulation 2023/1545 maintains this principle while expanding the substances covered.

A perfume ingredient list may therefore include “Parfum” to identify the fragrance composition while also listing the individual fragrance allergens that must be declared.

From a packaging-design perspective, this is increasingly relevant. The expansion of individually labelled allergens can result in longer ingredient lists for certain fragrance formulations.

Brands should therefore avoid finalising the physical design of a box or label before the necessary information about the finished formula is available.

Otherwise, they may discover too late that the space allocated to the INCI list is insufficient or that packaging artwork that was already prepared for printing needs to be modified.

Correct allergen identification begins with supplier documentation

Effective regulatory management depends on a reliable documentation chain. Manufacturers need accurate information about the raw materials they use, and a significant part of that information comes from suppliers.

When working with a fragrance compound, it is essential to obtain the technical documentation required to evaluate its use in the intended finished product. This documentation helps determine the relevant characteristics of the material and calculate the presence of certain substances in the final formula.

In addition to allergen information, fragrance development may require the review of documents relating to specifications, safety and conditions of use.

This is also where the IFRA Standards become relevant. They are an important industry reference for the safe use of fragrance ingredients. However, different levels of compliance should not be confused. Compliance with IFRA Standards does not automatically replace the legal obligations established under applicable cosmetics legislation.

A fragrance intended for the European market must comply with the EU Cosmetics Regulation, while also taking into account the relevant industry standards and supporting documentation.

The most effective approach is therefore to integrate these elements into the development process instead of reviewing them separately immediately before launch.

Allergens and formulation: the impact begins before labelling

Allergen management is not exclusively an administrative or labelling matter. It can also influence the formulation of the fragrance itself.

Imagine that a brand wants to build a perfume around particular natural raw materials. If these materials contribute significant quantities of substances subject to restrictions or individual declaration, the perfumer and technical team need to know this during development.

This does not necessarily mean that those materials need to be removed. Their concentrations may be adjusted, alternative raw materials may be considered, or certain accords may be reformulated while preserving the intended olfactory identity.

The key is having the information early enough.

Discovering a relevant limitation after the fragrance has already received final olfactory approval can require changes that affect the creative result. By incorporating regulatory criteria into the first development trials, creativity and compliance can progress in parallel.

This is particularly important in perfumery because even relatively small changes to a raw material can alter the balance of the overall composition. Replacing an ingredient is not always as simple as selecting another material with an apparently similar smell.

Safety and allergy: concepts that need to be communicated accurately

The presence of a fragrance allergen that requires declaration does not, by itself, mean that the perfume is unsafe for the general population. Individual labelling is particularly important because it enables people who are already sensitised to identify substances that may be relevant to them.

This is why brands need to use precise language when communicating about fragrance safety.

Claims such as “allergen-free” should be approached with particular caution. Given the complexity of fragrance compositions and the need to define precisely what such a claim means, it should not be used as a broad marketing statement without adequate substantiation.

Similarly, “natural” should not be presented as synonymous with “hypoallergenic” or “safer”. Natural aromatic materials can contain substances capable of triggering sensitisation reactions in certain individuals.

Accurate communication helps prevent misleading expectations while supporting consumer confidence in the product.

What happens if the fragrance concentration changes?

A decision that may initially appear purely commercial can have important regulatory consequences. Consider a brand that develops a fragrance using a particular concentration of fragrance compound and later decides to increase that concentration to create a more intense version.

The olfactory result will change, but so will the concentrations of the components present in the finished product.

The allergen calculation therefore needs to be reviewed.

A substance that was below the declaration threshold at one concentration could exceed it after the percentage of fragrance compound is increased. The conditions of use applicable to relevant ingredients may also need to be reassessed.

An Eau de Parfum, an Eau de Toilette and a more concentrated interpretation should therefore not automatically be assumed to share exactly the same ingredient information simply because they originate from a similar fragrance composition.

Each finished product needs to be assessed according to its own final formula.

The same principle applies to reformulation. Changing a raw material, switching supplier or adjusting the fragrance concentrate can make it necessary to review the technical documentation and labelling.

Oxidation and allergens: another factor to consider

European regulation also recognises the relevance of certain substances that can be transformed through processes such as air oxidation or bioactivation. Regulation (EU) 2023/1545 addresses prehaptens and prohaptens capable of transforming into known contact allergens and subjects them to the relevant regulatory approach.

This demonstrates why allergen management cannot be reduced to simply reading a list of ingredient names.

The stability of the fragrance and its storage conditions also matter. Light, temperature and oxygen can influence the evolution of certain aromatic components.

Fragrance development should therefore consider formulation, stability and packaging together. Appropriate storage and protection help maintain the intended characteristics of the product throughout its expected life.

The bottle, closure system and storage recommendations are consequently not purely aesthetic decisions. They form part of the technical development of the finished fragrance.

Why labelling should be based on the definitive formula

One mistake brands should avoid is preparing the definitive ingredient list too early in the development process.

The information appearing on the label needs to correspond to the product that will actually be manufactured and marketed. If the formula changes during development, the associated documentation needs to be reviewed.

This is particularly important in perfumery because the fragrance concentrate may go through multiple adjustments before the final version is approved. A modification can change not only the scent but also the presence and concentration of substances requiring individual declaration.

Good version control is therefore essential. The approved fragrance concentrate, manufacturing formula, supplier documentation and ingredient list should all correspond to the same final version.

Using outdated documentation could result in discrepancies between the actual product composition and the information appearing on the packaging.

With the expansion of European fragrance-allergen labelling requirements, this coordination has become even more important.

Product documentation and safety assessment

Fragrance allergens cannot be considered separately from the other obligations involved in marketing a perfume as a cosmetic product in the European Union.

Before being placed on the market, the product needs to have the documentation and safety assessment required under Regulation (EC) No 1223/2009. The complete composition and information concerning the raw materials are fundamental to the cosmetic product safety assessment.

This means that the information used to prepare the ingredient list should be consistent with the product’s technical documentation.

The objective is not simply to meet a formal requirement. Proper traceability makes it possible to understand what has been manufactured, which raw materials were used and under what conditions.

For brands, establishing this structure during the early stages of development significantly reduces the risk of discovering documentation or labelling problems shortly before launch.

Can a fragrance be developed with its allergen profile in mind from the beginning?

Yes. For certain projects, this can be a strategic development decision. If a brand establishes specific requirements concerning certain ingredients or substances within its initial brief, the perfumer can take them into account during the creative process.

However, every additional restriction can reduce the creative palette available to the perfumer. The more materials that are excluded, the more challenging it may become to reproduce certain olfactory profiles.

Restrictions should therefore have a clear purpose rather than being introduced simply because particular ingredients are perceived negatively from a marketing perspective.

A technically coherent strategy is to distinguish between requirements imposed by regulation, voluntary criteria related to brand positioning and restrictions that are genuinely necessary for the product concept.

This distinction avoids unnecessarily limiting the formulation while giving the perfumer a clear and workable brief.

Regulation and creativity should not be treated as opposing forces

One of the major challenges in fragrance development is ensuring that regulatory compliance does not become a final correction applied after the creative work has already been completed.

The perfumer needs sufficient freedom to build a distinctive olfactory identity, but also needs to understand the technical and regulatory boundaries of the product being developed.

When these two dimensions progress together, adapting a formula during its early versions is significantly easier than reformulating a fragrance that has already received final approval.

This is especially important at a time when fragrance-allergen requirements have evolved and brands need to prepare for broader ingredient-list and labelling obligations.

Regulation should not be viewed solely as an obstacle. It can also provide a framework for developing better-documented products and delivering more transparent information to consumers.

MS PARFUMS and allergen management during fragrance development

Creating a fragrance for a brand requires coordination between olfactory creation, raw materials, concentration, formulation, safety, regulation and labelling. Fragrance allergens affect almost every one of these areas.

At MS PARFUMS, allergen management should begin with the selection and documentation of the fragrance composition. As the concentrate and its percentage in the finished product are established, the presence of relevant substances can be calculated and the corresponding regulatory conditions reviewed.

This process needs to remain connected to formulation. If a raw material is changed during development or the fragrance concentration is modified, the impact on the finished composition should be reassessed.

The resulting technical information can then support the preparation of the ingredient list and the documentation required for the safety assessment and commercialisation of the product.

This methodology prevents allergen control from becoming a final check performed only when the product is almost ready to launch.

For a brand, the advantage is clear: the perfume is developed from the outset with both its olfactory identity and its technical and regulatory viability in mind.

Conclusion: understanding allergens is part of developing a successful fragrance

Fragrance allergens are an essential part of the technical management of a perfume. They may originate from both natural and synthetic raw materials, and their presence needs to be assessed according to the composition and concentration of the finished product.

European legislation establishes specific requirements for individual allergen declaration, and Regulation (EU) 2023/1545 significantly expanded the European framework for fragrance-allergen labelling. For substances subject to these requirements, the general thresholds for individual declaration are 0.001% in leave-on products and 0.01% in rinse-off products.

For a fragrance brand, this means that identification, formulation, documentation, safety and labelling need to be managed together. An accurate ingredient list cannot be prepared without knowing the definitive formula, and a formula should not be developed without considering the restrictions and requirements applicable to its ingredients.

Effective management begins with reliable raw-material information and continues through calculation at finished-product level, safety assessment and correct preparation of the label.

At MS PARFUMS, integrating these elements from the earliest stages makes it possible to transform an olfactory concept into a fragrance prepared for the market without separating creativity from compliance. Launching a perfume is not only about making it smell exceptional; it also means knowing exactly what it contains, how it has been formulated and what information the consumer needs to know.