How Safety Assessors Evaluate Cosmetic Ingredients: From Raw Materials to Formula Compliance

For this reason, the ingredients that compose the formula of cosmetics marketed in the European Union must meet certain requirements, including the ones mentioned in the EU Cosmetic Regulation 1223/2009 in order to guarantee their safety.

A safety assessor’s first task is to determine whether an ingredient and the raw material it is part of, are safe for human use under its intended conditions. Safety assessors must review every detail of a formula with precision, ensuring that safety conclusions are context-specific and scientifically sound. Each raw material must be thoroughly assessed, with complete documentation covering composition and impurities.

However, evaluating ingredients alone is not sufficient. The way these ingredients interact within a formula and how the product is used must also be considered. It involves a nuanced analysis of researched toxicological information about a specific substance, exposure, concentration, formulation, and usage patterns. This critical evaluation must be conducted by a qualified safety assessor.

The Safety Assessor will first review the formula provided, ensuring that the total amount of the ingredients equals 100%. The next step is to confirm the exact INCI (International Nomenclature of Cosmetic Ingredients) name for each ingredient in the cosmetic product and verify whether the ingredients are listed in the Annexes of the Cosmetic Regulation 1223/2009.

Safety Assessors follow a structured, internationally recognised methodology, largely based on the Scientific Committee on Consumer Safety (SCCS) Notes of Guidance for Testing and their Safety Evaluation (12th Revision). These notes outline the basic toxicity testing procedures necessary for assessing various human health-related toxicological endpoints. These procedures are internationally recognized, resulting from long-standing scientific consensus.

This process is based on four key pillars:

The first step is to determine whether an ingredient has inherent properties that could be harmful to human health. Toxicologists compile data after a carefully review from scientific literature, regulatory databases, historical usage data, and existing studies (both in vivo and in vitro) to identify any intrinsic properties that could pose risks such as:

• Chemical and physical specifications of cosmetic ingredients (chemical identity, physical form, solubility, etc.).
• For ingredients classified as nanomaterials, additional information such as particle size information will be required.
• Type of cosmetic ingredient (emollient, surfactant, viscosity controlling, etc.).
• CLP classification: Ingredients classified as CMR substances aren’t allowed in cosmetics, unless they are listed in one of the Annexes that permit their use
• Dermal absorption
• Skin irritation or sensitisation
• Mutagenicity
• Carcinogenicity
• Acute toxicity
• Reproductive or developmental toxicity
• Phototoxicity
• Clinical data
• Epidemiological studies

Any requisites of conditions of use to ensure the safety of the ingredient

Next, safety assessors evaluate the relationship between dose and effect, determining thresholds such as:

• PoD (Point of Departure)
• NOAEL (No Observed Adverse Effect Level)
• LOAEL (Lowest Observed Adverse Effect Level)

These benchmarks are critical for defining safe exposure limits in cosmetic formulations.

A key differentiator in cosmetic toxicology is the focus on real-life use. Safety Assessors calculate how much of a substance a consumer is exposed to during normal product use based on:

• Declared functions and uses of the ingredient as a cosmetic ingredient
• Maximal concentration within the formula
• Quantity used per application
• Frequency and duration of use
• Product type (leave-on vs rinse-off)
• Area of application (face, body, lips, etc.)
• Target population (adults, children, etc.)
• Type of cosmetic product where the ingredient will be present (the ingredients’ restrictions may vary in function of the final product function, like for example professional use)

This data is essential for accurately estimating systemic exposure and ensuring that safety assessments reflect real-world conditions.

Finally, risk characterization brings everything together and focuses on systemic effects.

A Margin of Safety (MoS) is calculated: an adequate Margin of Safety indicates that the ingredient can be used safely under the intended conditions of use. Regulatory authorities typically expect a sufficiently high MoS to account for uncertainties, including variability among individuals.

Modern toxicology is evolving rapidly, particularly in response to regulatory and ethical considerations. In the European Union, animal testing for cosmetic purposes has been banned for  ingredient or mixture of cosmetic ingredients has been in force since March 2009 (with the exception of repeated-dose toxicity, reproductive toxicity, and toxicokinetics tests, for which the ban came into force in March 2013), requiring toxicologists to rely on studies that were performed before the ban and/or validated non-animal methods (NAMs):

• In vitro testing methods
• Computational modelling (QSAR)
• Read-across from similar substances

These methods not only address ethical concerns but also enable faster and often more cost-effective assessments. However, while these tools offer powerful insights, they also demand advanced expertise to ensure accurate interpretation and regulatory acceptance.

While toxicological principles provide the scientific backbone, formula checks translate this science into regulatory compliance.

During a formula check, a Safety Assessor conducts a detailed review of the entire formulation, including:

• Verification of INCI ingredient names
• Identification of restricted or prohibited substances
• Assessment of concentration limits based on regulatory annexes
• Evaluation of impurities such as heavy metals
• Cross-checking supplier documentation for consistency

This step goes far beyond automated database screening. It involves a deep analysis of raw material documentation, ensuring that hidden components, impurities, or inconsistencies do not compromise the safety of the product. The simplest way to proceed is to collect all documents and tests available to provide to the safety assessors, and perform a Gap Analysis to outline the missing information and tests to complete the toxicological evaluation.

One of the most common challenges in toxicological evaluation is incomplete or inconsistent data in the raw materials documents. Each raw material is unique, with a specific composition and characteristics. This is why a case-by-case analysis will be carried out to determine what information is necessary for the toxicological evaluation of each raw material and its ingredients. Without accurate data, even the most sophisticated toxicological models cannot deliver reliable conclusions. The easiest way to proceed is to collect all available documents, they are critical tools for identifying impurities, verifying ingredient identity, and ensuring traceability. Depending on the nature of the cosmetic ingredients and the data found in the documents, the safety assessor will advise on the tests and other actions to be performed.

If, during the toxicology research of the ingredients or later while analysing the data in the Raw Materials documents, the Safety Assessor identifies a need for product reformulation, they will inform the client of the reasons and recommend necessary adjustments to meet safety and regulatory standards, ensuring the product remains compliant. Such modifications may include altering ingredient concentrations, replacing or removing ingredients, adding new ones, revising usage instructions (for example, reducing the area of exposure), or adding warnings (such as limiting use for children under 3 years old).

This is why you should consider working early on your cosmetic product development with a Safety Assessor, to avoid reformulation delays and compliance risks.

Toxicological evaluation is not an isolated scientific exercise. It is a key step within a broader regulatory process that includes:

1. Formula Check (ingredient and formulation compliance)
2. Cosmetic Product Safety Report (CPSR)
3. Label and claims verification
4. Product notification and market entry

Each stage builds on the previous one, transforming scientific data into a fully compliant, market-ready product.

Evaluating cosmetic ingredients is a meticulous and complex process grounded in science, guided by regulation. It requires a holistic approach, one that integrates toxicology, formulation science, regulatory compliance, and real-world use. From hazard identification to risk characterisation, every step plays a crucial role in ensuring that ingredients and the finished cosmetic product composed by them are safe and compliant.

Written by Taobé Consulting