What is Cosmetic Safety Assessment?
Cosmetic safety assessment is the systematic scientific evaluation of a cosmetic product to determine whether it is safe for human use under normal and reasonably foreseeable conditions. According to EU Regulation 1223/2009, every cosmetic product placed on the EU market must undergo a safety assessment performed by a qualified safety assessor.
Legal Requirement
The safety assessment process integrates multiple scientific disciplines:
- Toxicology — Evaluating potential harmful effects of ingredients
- Exposure science — Determining how much of a substance reaches the body
- Risk assessment — Characterizing whether exposure levels present acceptable risk
- Chemistry — Understanding ingredient interactions and stability
Legal Framework
Article 10: Safety Assessment Requirements
Article 10 and Annex I of the Cosmetics Regulation establish the safety assessment framework:
Article 10 Key Requirements
- Safety assessment must be performed before market placement
- Assessment must be documented in the CPSR (Part B)
- Only qualified safety assessors may sign the assessment
- Assessment must cover finished product, not just ingredients
- Must consider reasonably foreseeable use conditions
- Must be updated when new safety-relevant information emerges
Annex I Structure
The CPSR has two parts with distinct purposes:
| Element | Part A | Part B |
|---|---|---|
| Purpose | Technical dossier | Safety assessment |
| Content | Product information | Safety conclusions |
| Responsibility | Can be prepared by manufacturer | Must be signed by safety assessor |
| Includes | Formula, specs, stability, micro, packaging | Toxicology review, exposure assessment, conclusions |
Source: EU Regulation 1223/2009, Annex I
SCCS Notes of Guidance Overview
The SCCS Notes of Guidance (12th Revision, 2023) provides the methodological framework for cosmetic safety assessment. While technically guidance for SCCS opinions on specific ingredients, this document has become the de facto standard for all cosmetic safety assessments.
Key Principles from SCCS Notes
SCCS Safety Assessment Principles
- Assessment must be evidence-based using available scientific data
- Margin of Safety (MoS) approach is the primary risk characterization tool
- Exposure assessment must reflect realistic use conditions
- Read-across and in silico methods acceptable where appropriate
- Animal testing data cannot be generated but historical data may be used
- New Approach Methodologies (NAMs) increasingly important
The Safety Assessment Process
Step 1: Hazard Identification
Hazard identification determines what adverse effects each ingredient could potentially cause. This involves reviewing:
| Data Type | Source | Reliability |
|---|---|---|
| Published toxicology studies | Scientific literature, TOXNET | Varies by study quality |
| SCCS opinions | SCCS database | High — peer-reviewed |
| CIR (Cosmetic Ingredient Review) | CIR publications | High — expert panel reviewed (US-based; SCCS is EU equivalent) |
| REACH registration dossiers | ECHA database | Medium-High |
| Supplier safety data | TDS, SDS, certificates | Varies by supplier |
| In silico predictions | QSAR models | Supporting evidence only |
Source: SCCS Notes of Guidance
Data Quality Matters
Step 2: Dose-Response Assessment
Dose-response assessment determines the relationship between exposure level and adverse effect severity. Key outputs include:
| Endpoint | Definition | Typical Test |
|---|---|---|
| NOAEL | No Observed Adverse Effect Level | 90-day oral toxicity study |
| LOAEL | Lowest Observed Adverse Effect Level | Derived when NOAEL unavailable |
| BMD | Benchmark Dose | Statistical modeling of dose-response |
| POD | Point of Departure | Starting point for MoS calculation |
Source: SCCS Notes of Guidance
BMD Now Preferred
Step 3: Exposure Assessment (SED Calculation)
Exposure assessment quantifies how much of each ingredient reaches systemic circulation. The SCCS provides standardized exposure scenarios:
| Product Type | Amount Applied (g/day) | Retention Factor | Surface Area (cm²) |
|---|---|---|---|
| Body lotion | 7.82 | 1.0 (leave-on) | 15670 |
| Face cream | 1.54 | 1.0 (leave-on) | 565 |
| Hand cream | 2.16 | 1.0 (leave-on) | 860 |
| Lipstick | 0.057 | 1.0 (ingested) | N/A |
| Shampoo | 10.46 | 0.01 (rinse-off) | 1440 |
| Shower gel | 5.00 | 0.01 (rinse-off) | 17500 |
Source: SCCS Notes of Guidance, Appendix 4
Systemic Exposure Dose (SED) Calculation
The SED formula standardizes exposure to a per-kilogram body weight basis:
SED Calculation Formula
Step 4: Risk Characterization (Margin of Safety)
The Margin of Safety (MoS) is the primary metric for determining whether an ingredient is safe at its intended concentration:
MoS Calculation
The 100-fold safety factor accounts for:
| Factor | Magnitude | Accounts For |
|---|---|---|
| Interspecies | 10× | Differences between test animals and humans |
| Intraspecies | 10× | Variation within human population |
| Combined | 100× | Standard default safety margin |
Source: SCCS Notes of Guidance
Toxicological Endpoints Required
A comprehensive safety assessment addresses multiple toxicological endpoints:
| Endpoint | Purpose | Priority |
|---|---|---|
| Acute toxicity | Single-dose effects | For all ingredients |
| Irritation/corrosivity | Local skin/eye effects | Essential for leave-on |
| Skin sensitization | Allergic potential | Essential for all products |
| Dermal absorption | Systemic exposure | Critical for MoS |
| Repeated dose toxicity | Chronic effects, NOAEL | Required for MoS |
| Mutagenicity/genotoxicity | DNA damage potential | Required (no threshold) |
| Carcinogenicity | Cancer potential | When triggered by alerts |
| Reproductive toxicity | Fertility, developmental | When triggered |
| Toxicokinetics | ADME profile | Supporting information |
| Phototoxicity | Light-induced effects | For UV-absorbing ingredients |
Source: SCCS Notes of Guidance
New Approach Methodologies (NAMs)
Since the EU animal testing ban (Article 18) prohibits generating new animal test data for cosmetic purposes, safety assessments increasingly rely on NAMs.
Animal Testing Ban Timeline
Types of NAMs
| NAM Type | Examples | Application |
|---|---|---|
| In vitro assays | EpiSkin, SkinEthic, h-CLAT | Irritation, sensitization screening |
| In silico methods | QSAR, read-across, TTC | Hazard prediction, data gap filling |
| Biokinetic models | PBPK modeling | Dermal absorption, systemic exposure |
| Omics approaches | Toxicogenomics, metabolomics | Mechanism-based assessment |
| Integrated approaches | IATA, AOP | Weight-of-evidence conclusions |
Source: SCCS Notes of Guidance
Read-Across
Next Generation Risk Assessment (NGRA)
NGRA represents the evolution of cosmetic safety assessment, integrating NAMs into a cohesive framework:
NGRA Framework Steps
Exposure-Led Assessment
Start by defining realistic exposure scenarios for the specific product and use pattern.
Hypothesis-Driven Testing
Use existing knowledge to identify relevant hazards before generating new data.
Tiered Approach
Begin with simpler methods, progressing to more complex only if needed.
Bioactivity Comparison
Compare internal exposure concentrations to bioactivity thresholds.
Integrated Evidence
Combine multiple data streams using weight-of-evidence approach.
Special Considerations
Products for Children
Regulation 1223/2009 requires enhanced safety assessment for products intended for children under 3 years:
Additional Requirements for Children's Products
- Higher exposure estimates due to lower body weight
- Consider differences in skin permeability
- Account for mouthing behavior (toys, teethers)
- Restrict certain ingredients (e.g., certain preservatives)
- More conservative MoS may be appropriate
CMR Substances
Article 15 prohibits CMR substances, but Category 2 substances may be used if SCCS concludes they are safe:
- SCCS opinion must specifically address cosmetic use
- Assessment must demonstrate safe exposure levels
- Typically requires additional controls or concentration limits
Nanomaterials
SCCS Guidance on Nanomaterials requires:
- Physical-chemical characterization specific to nano form
- Assessment of nano-specific toxicity concerns
- Consideration of altered dermal penetration
- Specific CPNP notification requirements
Key Takeaways
Frequently Asked Questions
Under Article 10(2) of Regulation 1223/2009, safety assessors must hold a diploma or formal qualification in pharmacy, toxicology, medicine, or a similar discipline recognized by an EU Member State. 'Similar disciplines' typically include chemistry, biochemistry, dermatology, and related life sciences. The assessor must have adequate theoretical and practical knowledge.
The Margin of Safety (MoS) is the ratio of the Point of Departure (usually NOAEL from toxicity studies) to the Systemic Exposure Dose (SED). The 100-fold threshold accounts for two 10× safety factors: interspecies extrapolation (animal to human) and intraspecies variation (individual human differences). MoS ≥ 100 indicates acceptable safety.
Existing animal test data (generated before the ban) can be used. Data from non-cosmetic purposes (e.g., pharmaceutical, REACH) can also be used. However, you cannot commission new animal testing specifically for cosmetic safety assessment. NAMs must be used for any new data generation.
Dermal absorption is the fraction of an applied substance that penetrates through skin into systemic circulation. It's critical for MoS calculation because systemic exposure (SED) depends on how much ingredient actually enters the body. Default absorption values or specific study data can be used.
The CPSR must be updated whenever new safety-relevant information becomes available — this includes new toxicological data, changes in ingredient restrictions, formulation changes, or reports of adverse effects. There's no fixed timeline, but annual review is good practice.
Threshold of Toxicological Concern (TTC) is a screening tool for substances with limited data. If exposure is below TTC thresholds (typically 1.5 µg/kg bw/day for non-genotoxic substances), the substance is considered of low concern. TTC cannot be used for substances with known high-potency endpoints or certain structural alerts.
Yes. 'Natural' does not mean safe. Natural ingredients require the same rigorous assessment as synthetic ones. Complex natural mixtures (essential oils, plant extracts) present additional challenges requiring assessment of major components and potential for allergens, irritants, or toxic constituents.
An Adverse Outcome Pathway (AOP) describes the mechanistic sequence from molecular initiating event to adverse health outcome. AOPs help design testing strategies, interpret NAM data, and support weight-of-evidence conclusions. They're particularly useful for endpoints like skin sensitization where validated AOPs exist.