Endocrine disruptors in cosmetics: How to identify 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, in its offspring, or within (sub-)populations".

This definition, now reflected in Commission Delegated Regulation (EU) 2023/707 on the classification and labeling of substances, underscores one essential point: it is not enough 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 body’s major functions : growth, metabolism, reproduction, neurological development, and stress response. Hormones act at very low concentrations via through 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. Likewise, 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.

At the mechanistic level, endocrine disruptors can act in several ways : mimic the action of a natural hormone by binding to its receptor, block hormonal activity by preventing that binding, or alter the synthesis, transport, metabolism, or elimination of hormones. It should also be noted that exposure to endocrine disruptors can occur via different routes—dermal, respiratory, or oral—depending on how the substances are used. In the case of cosmetics, the skin serves as the primary potential exposure route, but it is not the only one. Inhalation, through sprays and fragrances, and ingestion, through lip products, are also possible.

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

• Fertility disorders.

  Some substances suspected of being endocrine disruptors have been associated with impaired semen quality in men (decreased sperm concentration or motility). In women, menstrual cycle disturbances or an increased risk of polycystic ovary syndrome have been reported. These effects could be related to interference with estrogens, androgens and/or progesterone, sex hormones, via activation or blockade of their receptors. Altered hormonal signaling can disrupt spermatogenesis, ovulation, or the hypothalamic-pituitary axis that regulates reproductive function.

• Abnormalities in reproductive development.

  In utero exposure may disrupt the differentiation of the genital organs. Some studies have demonstrated 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 necessary for normal differentiation.

• Precocious puberty.

  Research suggests that exposure to certain molecules with estrogenic activity may advance the onset of puberty, particularly in girls. Earlier puberty itself is associated with an increased risk of metabolic disorders and hormone-dependent diseases in adulthood. The proposed mechanism involves premature stimulation of the hypothalamic-pituitary-gonadal axis, which triggers sexual maturation. Estrogen-mimicking compounds could activate this hormonal cascade earlier.

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

  Some substances are under investigation for their potential role in dysregulating energy metabolism. By interfering with hormones that regulate 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 signaling 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 testis. The hypothesis is based on chronic stimulation of hormonal receptors (estrogenic or androgenic), which may promote cell proliferation in tissues reliant on these signals.

• Effects on the immune system and neurological development.

  Some studies are investigating a possible link between exposure to endocrine-disrupting chemicals and alterations in brain development or immune response. Indeed, thyroid and steroid hormones play a key role in brain maturation and immune balance. Any disruption of these hormonal axes during critical periods could influence these processes.

These effects are not uniform and depend heavily on the dose, exposure duration, and developmental stage at the time of exposure, with the prenatal period, childhood, and pregnancy representing periods of heightened vulnerability.

European regulations on chemicals are considered among the strictest in the world. Their objective is clear: to identify, assess, and, where necessary, restrict or ban substances that may pose a risk to human health or the environment. For several years, endocrine disruptors have been under particular scientific and regulatory scrutiny. They are not governed by a single piece of legislation but incorporated into multiple regulations, among which:

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

  It oversees the registration, evaluation, and authorization of chemical substances within the European Union. Substances exhibiting endocrine-disrupting properties and for which scientific evidence indicates serious adverse effects may be classified as “Substances of Very High Concern” (SVHC). They are then subject to a specific authorization or restriction regime.

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

  The CLP Regulation governs the classification, labeling, and packaging of chemical substances. Since 2023, new hazard classes specific to endocrine disruptors have been introduced. These include 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 labeling requirements will be phased in between 2025 and 2026.

As a complement to the European framework, France established in 2014 a National Strategy on Endocrine Disruptors (SNPE), renewed in 2019 (SNPE2). Its goal is to reduce population and environmental exposure to these substances, notably through developing research, prioritizing certain molecules, and raising public awareness. The AGEC Act (Anti-Waste for a Circular Economy) introduced a requirement to provide information on the presence of confirmed, presumed, or suspected endocrine disruptors in certain product categories, including cosmetics. The ministerial decree published in September 2023 defines the lists of relevant substances. There is no single, universal list but several identification schemes, including that of ANSES (the French Agency for Food, Environmental and Occupational Health & Safety), which catalogs over 900 substances with potential endocrine activity.

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

In the cosmetics industry, several substances have been suspected, classified, or discussed for their endocrine-disrupting properties. It is important to note that they do not all exhibit the same level of evidence, nor share the same regulatory status: some are banned, others are restricted, and still others are currently under assessment. The table below presents 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 regarding substances suspected of acting as endocrine disruptors and we exclude them from our products.

When evaluating the safety of a chemical substance, it is generally studied in isolation. However, in real life, we are simultaneously exposed to a multitude of compounds : pesticide residues, cosmetic ingredients, plasticizers, medications, atmospheric pollutants... This combined exposure raises the following question in toxicology: what if the risk does not stem from a single molecule, but from their interaction? This is known as the "cocktail effect."

The "cocktail" effect refers to the phenomenon where multiple substances, each considered safe when taken individually, can collectively produce an additive or synergistic effect 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 when taken separately—ethinylestradiol, a synthetic estrogen, and trans-nonachlor, an organochlorine pesticide—could 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 known as cooperative binding. Thus, the mixture triggers hormonal activation at much lower concentrations than those required for each substance alone.

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

Considering that tens of thousands of chemical substances coexist in our environment, taking into account the "cocktail" effect today represents a major challenge for toxicology and the assessment of risks related to endocrine disruption.

• 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).