How to Integrate Environmental Properties into the Safety Assessment of Cosmetic Ingredients
- 2 days ago
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Updated: 50 minutes ago
The safety of cosmetic products is generally assessed from the perspective of human health, considering endpoints such as skin irritation, skin sensitisation, systemic toxicity, and endocrine disruption. However, the environmental properties of cosmetic ingredients are becoming increasingly important in substance assessment processes and product development strategies, particularly when selecting formulation ingredients.
This growing focus is driven by several converging factors:
increasing consumer expectations;
corporate sustainability (CSR/ESG) strategies;
evolving environmental regulations;
and the development of environmental impact assessment and scoring tools for cosmetic products.
Despite this progress, several concepts are still frequently oversimplified or misunderstood.
→ A biodegradable substance is not necessarily harmless to aquatic organisms.
→ Likewise, some substances may become substances of concern well before any formal regulatory restriction is introduced.
→ Finally, the natural origin of an ingredient does not, by itself, guarantee a low environmental impact.
The purpose of this article is to review the key concepts needed to understand how environmental properties can be integrated into the safety assessment of cosmetic ingredients.
1. Ecotoxicity and Environmental Fate: Two Complementary Pillars
The environmental profile of a substance is primarily based on two major categories of information:
ecotoxicity, which characterises its effects on living organisms;
environmental fate, which describes how the substance behaves once released into the environment.
Although complementary, these concepts address different scientific questions.
Ecotoxicity
Ecotoxicity aims to characterise the effects of a substance on organisms exposed under environmental conditions, including:
aquatic organisms such as fish, algae and aquatic invertebrates;
terrestrial organisms, including soil macroorganisms and microorganisms;
and many other environmental species.
Studies may investigate either short-term exposure (acute toxicity) or long-term exposure (chronic toxicity).
The most commonly used endpoints include:
EC50 and LC50 for acute toxicity;
EC10 and NOEC for chronic toxicity.
→ These data are used to characterise the environmental hazard of a substance.
Environmental fate
Once released into the environment, a substance may partition between different environmental compartments (including water, soil, sediment and air) and undergo various transformation processes.
Key parameters evaluated include:
water solubility;
volatility;
degradation;
biodegradability;
mobility;
bioaccumulation;
adsorption to particles in water, sediment, soil, air and living organisms.
→ Environmental fate plays a major role in assessing:
environmental exposure;
long-range transport potential;
persistence;
the potential for accumulation in living organisms;
and the overall environmental risk.
Under cross-sector regulations such as REACH, as well as sector-specific legislation such as the Biocidal Products Regulation (BPR), ecotoxicity and environmental fate data are inseparable components of a comprehensive environmental assessment.
Regulatory framework
Requirements relating to environmental information are primarily established under:
Regulation (EC) No 1907/2006 (REACH);
Regulation (EC) No 1272/2008 (CLP);
and the guidance documents published by the European Chemicals Agency (ECHA).
By contrast, the European Cosmetics Regulation (EC) No 1223/2009 does not require a comprehensive environmental assessment of cosmetic ingredients before a cosmetic product is placed on the market. Nevertheless, other environmental regulations may indirectly affect ingredients used in cosmetic formulations.
Some cosmetic ingredients are known to exhibit high toxicity to aquatic organisms. Frequently cited examples include BENZOPHENONE-3 and certain ethoxylated surfactants such as LAURETH-3.
2. Environmental Hazard Classifications under the CLP Regulation
Ecotoxicological properties may lead to an environmental hazard classification under Regulation (EC) No 1272/2008 (CLP).
The best-known environmental hazard classes are:
Aquatic Acute;
Aquatic Chronic.
These classifications primarily consider:
aquatic toxicity;
biodegradability;
bioaccumulation potential.
Substances exhibiting very high toxicity to aquatic organisms may therefore be classified as:
Aquatic Acute Category 1;
Aquatic Chronic Category 1.
Where appropriate, M-factors are assigned according to the lowest aquatic toxicity value, increasing the contribution of these substances when calculating the classification of mixtures.
Today, however, environmental concerns extend well beyond aquatic toxicity alone.
In 2023, several new environmental hazard classes were introduced under the CLP Regulation:
Endocrine Disruptor for the Environment (ED ENV);
Persistent, Bioaccumulative and Toxic (PBT);
very Persistent and very Bioaccumulative (vPvB);
Persistent, Mobile and Toxic (PMT);
very Persistent and very Mobile (vPvM).
These properties are now subject to close regulatory scrutiny because they help identify substances likely to cause long-term environmental impacts, often well before formal regulatory restrictions are adopted.
Certain cyclic silicones, UV filters and fluorinated substances illustrate this growing trend towards proactive regulatory risk management.
Bumetrizole, used as a UV filter, is another example of a substance identified as a concern because of its persistence and bioaccumulation potential and has been concluded to meet the vPvB criteria.
Other cosmetic ingredients also illustrate concerns related to persistence and bioaccumulation. For example, C9-15 Fluoroalcohol Phosphate, which belongs to the PFAS family, is associated with the exceptional environmental persistence characteristic of fluorinated substances.
Similarly, Octrizole (INCI: Octrizole), used as a UV absorber to protect cosmetic formulations from photodegradation, has also been identified as exhibiting concerning persistence and bioaccumulation properties and has been concluded to meet the vPvB criteria.
These examples illustrate how PBT and vPvB criteria have become key drivers for regulatory anticipation and ingredient substitution strategies.
→ Today, these properties are major considerations when anticipating future regulatory developments and identifying potential substitution candidates.
3. Biodegradability: A Frequently Misunderstood Concept
Biodegradability is probably the best-known environmental property among the general public. However, it is also one of the most frequently oversimplified.
A biodegradable substance is not necessarily of low concern for the environment.
Conversely, a substance exhibiting low immediate toxicity may still raise environmental concerns if it persists in the environment over extended periods.
Biodegradability studies evaluate the ability of microorganisms to degrade a substance under standardized experimental conditions.
Examples of cosmetic ingredients known to exhibit low biodegradability include:
certain benzophenones, including BENZOPHENONE-1, BENZOPHENONE-2, BENZOPHENONE-6, and BENZOPHENONE-8;
BHT;
several modern UV filters;
ETIDRONIC ACID (INCI: ETIDRONIC ACID);
certain rosin-derived resins (INCI names including COLOPHONIUM, GLYCERYL ROSINATE, and HYDROGENATED ROSINATE);
certain synthetic hydrocarbons.
Biodegradability of mixtures
For finished cosmetic products, biodegradability may be estimated based on the properties of the individual ingredients.
However, this approach has several limitations:
environmental data are not available for all ingredients;
experimental test conditions do not always reflect real environmental conditions;
interactions between ingredients may influence the biodegradation of the finished formulation.
4. How Environmental Regulations Influence Cosmetic Ingredients
The European Cosmetics Regulation (EC) No 1223/2009 does not require a comprehensive environmental assessment before cosmetic products are placed on the market.
However, several other regulatory frameworks may directly affect the ingredients used in cosmetic formulations, including:
REACH;
CLP;
specific environmental restrictions.
The well-known example of cyclic silicones
The cyclic silicones:
Cyclotetrasiloxane (D4);
Cyclopentasiloxane (D5);
Cyclohexasiloxane (D6),
are probably the best-known example of the impact that environmental regulations can have on cosmetic ingredients.
Their PBT and vPvB properties led to the introduction of restrictions under the REACH Regulation, with direct consequences for certain categories of cosmetic products, particularly rinse-off products.
These restrictions were introduced through Commission Regulation (EU) 2018/35, amending Annex XVII to REACH.
→ Although these restrictions do not originate from the Cosmetics Regulation itself, they have a direct impact on the formulation of certain cosmetic products, especially rinse-off products.
5. Anticipating Rather Than Reacting: The Strategic Value of Environmental Data
Environmental data are no longer used solely to demonstrate compliance with existing regulations.
They have also become valuable decision-support tools for:
formulators;
cosmetic safety assessors;
regulatory affairs professionals;
sustainability (CSR/ESG) teams.
The objective is to identify, as early as possible, substances that may become problematic in the future.
Ingredients may therefore be excluded:
because they are already subject to regulatory restrictions;
to anticipate future regulatory developments;
or as part of a voluntary environmental sustainability strategy.
→ Within this proactive approach, PBT, vPvB, and Endocrine Disruptor for the Environment (ED ENV) classifications are receiving increasing attention.
Today, the COSMETICK database includes ecotoxicological and environmental profiles for more than 2,200 cosmetic ingredients. Among these, 140 have been identified as presenting a high to very high level of environmental concern.
These include:
several UV filters;
certain parabens;
various silicones;
but also ingredients that are less commonly associated with environmental concerns, such as BAKUCHIOL, PROPYL GALLATE, and MENTHOXYPROPANEDIOL.
This information helps companies prioritize substitution efforts while anticipating future regulatory developments.
6. Towards More Comprehensive Environmental Assessments
The environmental assessment of a cosmetic product extends beyond the ecotoxicological profile of its ingredients.
More comprehensive approaches are now being developed, incorporating factors such as:
Life Cycle Assessment (LCA);
carbon footprint;
water consumption;
packaging;
environmental scoring of raw materials.
Initiatives such as the Green Impact Index and EcoBeautyScore illustrate this shift towards multi-criteria environmental assessment.
Within this broader context, ecotoxicological data represent an essential, although not exclusive, component of the overall environmental evaluation of cosmetic products.
COSMETICK provides ecotoxicological and environmental property data for cosmetic ingredients, supporting Life Cycle Assessments (LCA) and other environmental impact assessment and scoring methodologies.
7. Data Gaps and Limitations of Environmental Assessments
As in human toxicology, environmental data remain incomplete for many substances.
The most common challenges include:
the absence of biodegradability data;
limited ecotoxicological information;
methodological differences between studies;
the need for read-across or other scientific extrapolations.
These data gaps can make environmental assessments particularly challenging for:
complex mixtures;
certain naturally derived raw materials;
substances that remain insufficiently characterized.
Examples of widely used cosmetic ingredients for which environmental data remain limited include:
POLYHYDROXYSTEARIC ACID;
SACCHARIDE ISOMERATE;
SCLEROTIUM GUM;
ISONONYL ISONONANOATE.
Managing these uncertainties has become one of the major challenges of modern environmental assessment.
Conclusion
The environmental impact of cosmetic ingredients depends on several complementary dimensions, including:
ecotoxicity;
biodegradability;
persistence;
bioaccumulation;
regulatory status;
and, increasingly, Life Cycle Assessment (LCA).
→ These properties are no longer used solely for hazard classification. They have become valuable tools for informed decision-making, responsible formulation, and proactive regulatory anticipation.
As environmental requirements continue to evolve worldwide, the ability to organize, interpret, and exploit ecotoxicological data is becoming an essential capability for the cosmetics industry.
Above all, one key message should be remembered: A biodegradable substance is not necessarily safe for the environment.
Authors: Clarisse Bavoux & Cyril Durou
