Endocrine disruptors in cosmetics: how to recognise them and what are the health risks?

An endocrine disruptor is defined by the World Health Organization (WHO) as "a substance or mixture that alters the functions of the endocrine system and thereby induces adverse effects in an intact organism, its progeny or within (sub-)populations".

This definition, now incorporated in Delegated Regulation (EU) 2023/707 on the classification and labelling of substances, emphasises one essential point: it is not sufficient for a substance to interact with the hormonal system, it must cause a demonstrated deleterious effect.

As a reminder, the endocrine system comprises all the glands and hormones that regulate the major functions of the body : growth, metabolism, reproduction, neurological development, and even the stress response. Hormones act at very low concentrations via specific receptors and are subject to highly precise feedback mechanisms. For a substance to be formally identified as an endocrine disruptor, three criteria must be met: it must exhibit endocrine activity, cause an adverse health effect, and a biologically plausible link must be established between that hormonal activity and the observed effect.

In other words, not all substances with hormonal activity are automatically classified as endocrine disruptors. Similarly, a substance that is toxic to reproduction is not necessarily an endocrine disruptor if its mechanism of action does not involve altering the hormonal system.

Mechanistically, endocrine disruptors can act in several ways : mimic the action of a natural hormone by binding to its receptor, block hormonal activity by preventing this binding, or alter the synthesis, transport, metabolism or elimination of hormones. It is also worth noting that exposure to endocrine disruptors can occur through different routes, including dermal, respiratory or oral, depending on the context of use of the substances. In the case of cosmetics, the skin is the primary potential route of exposure, but not the only one. Indeed, inhalation via sprays and perfumes, and ingestion via lip products are also possible.

The risks posed by endocrine disruptors are real. Among the main identified effects are:

• Fertility disorders.

  Certain suspected endocrine-disrupting substances have been linked to altered semen quality in men (reduced sperm count or motility). In women, disruptions to the menstrual cycle or an increased risk of polycystic ovary syndrome have been reported. These effects may be related to interference with the oestrogens, androgens and/or the progesterone, sex hormones, via receptor activation or blockade. Altered hormonal signalling can disrupt spermatogenesis, ovulation or the hypothalamo-pituitary balance that regulates reproductive function.

• Abnormalities in reproductive development.

  Exposure during intrauterine life may disrupt the differentiation of the genital organs. Some studies have shown an association between prenatal exposure to certain substances and male genital malformations. During embryogenesis, sex hormones orchestrate the development of the reproductive organs. Interference with androgens or their receptors at this critical stage can alter the signals required for normal differentiation.

• Precocious puberty.

  Research suggests that exposure to certain molecules with oestrogenic activity could advance the onset of puberty, particularly in girls. Earlier puberty is itself associated with a higher risk of metabolic disorders and hormone-dependent conditions in adulthood. The proposed mechanism centres on premature activation of the hypothalamic–pituitary–gonadal axis, which triggers sexual maturation. Oestrogen-mimicking compounds may thus activate this hormonal cascade sooner.

• Metabolic disorders (obesity, diabetes, etc.).

  Some substances are being investigated for their potential role in disrupting energy metabolism. By interfering with hormones involved in the regulation of appetite, lipid storage or insulin sensitivity, they could contribute to the development of obesity or type 2 diabetes. In particular, certain compounds may act on nuclear receptors involved in adipocyte differentiation or on insulin signalling pathways, thereby altering energy homeostasis.

• Hormone-dependent cancers.

  Prolonged exposure to substances capable of interacting with hormonal receptors could theoretically influence the risk of hormone-sensitive cancers, such as those of the breast, prostate or testicle. The hypothesis is based on chronic stimulation of hormonal receptors (oestrogenic or androgenic), which may promote cell proliferation in tissues dependent on these signals.

• Effects on the immune system and neurological development.

  Certain studies explore a potential link between exposure to endocrine disruptors and alterations in brain development or immune response. Indeed, thyroid and steroid hormones play a key role in brain maturation and immune homeostasis. Any disruption of these hormonal axes during critical periods could influence these processes.

These effects are not always observed and depend strongly on the dose, the duration of exposure and the developmental stage at the time of exposure, with the prenatal period, childhood and pregnancy representing periods of high vulnerability.

European chemical legislation is considered one of the most stringent in the world. Its objective is clear: to identify, evaluate and, when necessary, restrict or prohibit substances that may pose a risk to human health or the environment. For several years, endocrine disruptors have been the subject of particular attention, both scientifically and in regulatory terms. They are not regulated by a single text, but integrated into several regulations, among which:

• The REACH Regulation (EC No. 1907/2006).

  It manages the registration, evaluation and authorisation of chemical substances within the European Union. Substances exhibiting endocrine-disrupting properties and for which scientific evidence indicates serious effects can be classified as “substances of very high concern” (SVHC). They are then subject to a specific authorisation or restriction regime.

• The CLP Regulation and the Commission Delegated Regulation (EU) 2023/707.

  The CLP Regulation governs the classification, labelling and packaging of chemical substances. Since 2023, new hazard classes specific to endocrine disruptors have been introduced. These are Category 1, for known or presumed endocrine disruptors, and Category 2, for suspected endocrine disruptors. These classifications are accompanied by specific hazard statements (EUH380, EUH381 for human health; EUH430, EUH431 for the environment). The new labelling requirements will be phased in between 2025 and 2026.

In addition to the European framework, France implemented as early as 2014 a National Strategy on Endocrine Disruptors (SNPE), renewed in 2019 (SNPE2). Its objective is to reduce exposure of the population and the environment to these substances, notably through the development of research, the priority identification of certain molecules and public information. The AGEC Act (Anti-Waste for a Circular Economy) has introduced a requirement to inform on the presence of confirmed, presumed or suspected endocrine disruptors in certain categories of products, including cosmetics. The ministerial decree published in September 2023 establishes the lists of substances concerned. There is no single, universal list, but several identification schemes, including that of ANSES (French Agency for Food, Environmental and Occupational Health & Safety), which catalogues over 900 substances with potential endocrine activity.

Endocrine disruptors are now incorporated into a comprehensive and evolving European regulatory framework.

In the cosmetics sector, several substances have been suspected, classified or discussed for their endocrine-disrupting properties. It is important to note that they do not all have the same level of evidence or regulatory status: some are prohibited, others restricted, and still others are subject to ongoing evaluation. The table below provides a non-exhaustive list of ingredients frequently cited in the scientific literature and by health authorities.

At Typology, as a precautionary principle and in accordance with our formulation charter, we are very vigilant about substances suspected of acting as endocrine disruptors and we exclude them from our products.

When assessing the safety of a chemical substance, it is typically studied in isolation. However, in real life, we are simultaneously exposed to a multitude of compounds : pesticide residues, cosmetic ingredients, plasticisers, pharmaceuticals, air pollutants… This combined exposure raises the following question in toxicology: what if the risk does not come from a single molecule, but from their interaction? This is referred to as the “cocktail” effect.

The "cocktail effect" refers to the phenomenon where multiple substances, each considered safe when taken separately, can together produce an additive or synergistic impact on the endocrine system.

Research conducted by teams from Inserm and CNRS in Montpellier has provided an initial mechanistic proof in vitro. The researchers demonstrated that two weakly active molecules on their own, ethinylestradiol, a synthetic oestrogen, and trans-nonachlor, an organochlorine pesticide, can simultaneously bind to the same nuclear receptor and activate it synergistically. At the molecular level, the binding of the first compound facilitates the binding of the second: this is referred to as cooperative binding. Thus, the mixture triggers hormonal activation at concentrations much lower than those required for each substance alone.

In light of this mechanism, one might wonder whether the traditional substance-by-substance assessment could underestimate certain risks. That being said, it is important to emphasize that these results represent a proof of concept in vitro. The application to real-life scenarios still requires further research.

Given the fact that tens of thousands of chemical substances coexist in our environment, accounting for the "cocktail" effect is now a major challenge in toxicology and the assessment of endocrine disruption risks.

• SASCO A. J. & al. Cosmetics as endocrine disruptors: Are they a health risk? Reviews in Endocrine Metabolic Disorders (2015).

• BOURGUET W. & al. Synergistic activation of human pregnane X receptor by binary cocktails of pharmaceutical and environmental compounds. Nature Communications (2015).

• IUGHETTI I. & al. New insights on the effects of endocrine-disrupting chemicals on children. Jornal de Pediatria (2021).

• RALLIS E. & al. Endocrine disruptors in cosmetic products and the regulatory framework: Public health implications. Cosmetics (2023).

• ZHOU L. & al. Interference mechanisms of endocrine system and other systems of endocrine-disrupting chemicals in cosmetics – In vitro studies. International Journal of Endocrinology (2024).

• KASAMBA E. & al. Additives and endocrine disruptors in cosmetic products for use by children under 2 years old: A danger not mentioned in advertisements. European Journal of Applied Sciences (2024).

• Thèse de Téo TODESCO. Les perturbateurs endocriniens dans les cosmétiques (2024).

• MITJANS M. & al. Assessment of endocrine-disrupting properties in cosmetic ingredients: Focus on UV filters and alternative testing methods. Cosmetics (2025).

• BOUWMEESTER M. C. & al. Inventory of possible endocrine disrupting chemicals used in cosmetic products. Critical Reviews in Toxicology (2025).