How is the classification of cosmetic ingredients established?

The evaluation of cosmetic ingredients takes into account both the effects of these compounds on human health and their environmental impacts. It is based on two complementary analyses: a toxicological assessment and an ecotoxicological assessment.

A cosmetic ingredient is classified as red (high-risk) 🔴 on Yuka if all three of the following criteria are met:

1. Serious health effects on health or the environment

The cosmetic ingredient itself, or contaminants potentially present in the ingredient, are associated with serious effects on health or the environment.

Serious effects on human health are defined as those likely to increase the risk of acute reactions or chronic diseases, such as cancer or toxicity affecting one or more target organs (for example: pancreas, liver, kidneys, lungs, blood). Serious effects also include a high skin sensitization potential, severe allergic reactions, as well as complex biological or metabolic disruptions, such as effects on the endocrine, reproductive or nervous systems, and DNA damage.

From an environmental perspective, serious effects are those causing significant harm to ecosystems, through acute and/or chronic toxicity and/or endocrine disruption observed in species belonging to different trophic levels (algae, micro-organisms, invertebrates, corals, fish and other vertebrates) at concentrations comparable to those leading to an environmental hazard classification in category 1 under the European CLP Regulation No. 1272/2008.

2. High level of evidence

The link between the ingredient and at least one of its serious effects on health or the environment is supported by robust evidence derived from:

• An opinion or official classification by a recognized authority (IARC, ECHA, SCCS, ANSES, US EPA, INERIS, Health Canada, etc.), and/or
• A body of converging scientific evidence from complementary methodological approaches (animal studies, in vitro experiments, epidemiological studies, skin tolerance tests, analyses of interactions with hormones, hormone receptors or other key elements of metabolism, in silico studies predicting toxicity through computer modeling, etc.).

3. Estimated exposure of concern

The estimated exposure of the consumer or the environment can reach or exceed levels of concern for health or leave an insufficient margin of safety, for all or part of the population (including for certain age groups or specific regions) or for living organisms.

Our exposure assessment notably takes into account, depending on available data:

• The estimated concentration of the ingredient in products (declared usage data, analytical data, maximum permitted values, health authorities’ estimates);
• The frequency and quantities of use of these products under normal conditions;
• The accumulation of exposure due to the presence of the ingredient in several cosmetic products that may be part of the same routine;
• The form in which the ingredient is used, particularly in the case of nanoparticles, whose very small size may increase biological reactivity, tissue accumulation and potentially toxicity;
• The rate of skin penetration for cosmetics applied to the skin;
• Other relevant exposure routes depending on the type of product, notably inhalation (aerosols, sprays), accidental ingestion (lip products) or exposure of mucous membranes (intimate hygiene products);
• Different population groups, including infants, children, adolescents, adults, pregnant women, the elderly, as well as individuals with dry, damaged and/or atopic skin, in whom impairment of the skin barrier may facilitate substance penetration.

From an environmental perspective, ecosystem exposure notably takes into account, depending on available data:

• The physico-chemical properties of substances;
• Their mobility across environmental compartments (water, air, soil);
• Their persistence, notably through biodegradability test results;
• Their bioaccumulation potential in living organisms;
• Estimates of quantities released into the environment as a result of human activities.

Yuka’s scientific team considers the level of exposure of concern for human or environmental health when at least one of the following situations is observed, for all or part of the population:

• Exceeding a threshold of concern for health or the environment (for example: margin of safety, derived no-effect level, predicted no-effect concentration for the environment) identified by a risk assessment authority (for example: ECHA, SCCS, ANSES, US EPA, INERIS, Health Canada);
• Exceeding a threshold of concern identified in one or more independent studies with a high level of evidence according to toxicological standards established by official bodies (such as IARC, JECFA, EFSA or INERIS);
• Absence of an exposure threshold that can be considered safe for health or the environment. Certain substances suspected of disrupting the endocrine system or having carcinogenic and genotoxic properties could theoretically cause harmful effects even at very low exposure levels. In such cases, risk assessment authorities recommend reducing exposure to the lowest possible level, as no dose can be considered entirely free of harmful effects.

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A cosmetic ingredient is classified as orange (moderate risk) 🟠 on Yuka when the three above criteria are not fully met. For example:

• Available scientific data indicate a potentially significant exposure, but the degree of certainty/evidence regarding effects on health and/or the environment remains insufficient;
• Exposure data suggest a possible risk of exceeding a threshold of concern, or a potential for bioaccumulation that could lead to effects with long-term exposure, but remain insufficient to characterize this risk with certainty.

A cosmetic ingredient is classified as yellow (low risk) 🟡 on Yuka when:

• Effects on health and/or the environment are considered less concerning. In terms of health, this includes for example moderate risks of irritation or eye discomfort, a moderate risk of skin sensitization (i.e. developing a skin allergy), the risk of facilitating the penetration of other substances through the skin, or photosensitivity (i.e. the risk of causing reactions upon exposure to light). For the environment, this includes, for example, ingredients that are only partially removed during wastewater treatment, potentially leading to the release of poorly biodegradable substances into the environment;
• Observed effects could be significant for health and/or the environment, but available scientific evidence remains insufficient. In these situations, the risk is considered suspected;
• The level of exposure via cosmetic products is significant, while remaining below thresholds of concern for health and/or the environment under normal conditions of use;
• Environmental exposure to the substance is limited, but the manufacturing process has an identified environmental impact (extraction of fossil or mineral resources, energy-intensive chemical synthesis, significant use of solvents).

A cosmetic ingredient is classified as green (risk-free) 🟢 on Yuka when to date, no risk to human or environmental health at the doses commonly used in cosmetics has been identified by scientific sources presenting a high degree of evidence.