The use of makeup products is part of the daily routine of millions of people around the world. From a social, aesthetic, and even psychological perspective, these products serve important functions. However, from a biological and toxicological standpoint, their prolonged use raises questions that have begun to be explored more deeply in recent scientific literature. The question is no longer only what these products do at a superficial level, but how they interact with the body over time.

The skin, far from being a completely impermeable barrier, is a dynamic organ with absorptive capacity. Various studies have shown that small, lipophilic, and uncharged molecules can pass through the stratum corneum via passive diffusion, especially when they remain in prolonged contact with the skin surface. Factors such as temperature and hydration can increase this permeability, which is particularly relevant in the context of the daily use of facial cosmetics. This repeated exposure turns makeup products into a potential source of chronic contact with multiple chemical compounds.

In this context, a study published in the International Journal of Environmental Research and Public Health analyzed the composition of 50 facial makeup products available on the European market, evaluating the presence of substances described in the literature as potentially carcinogenic. The results indicated that all analyzed products contained at least one compound with this type of potential. This finding does not imply a direct causal relationship between cosmetic use and cancer development, but it does highlight the need to consider the effects of prolonged and cumulative exposure.

Among the identified compounds, parabens stand out due to their widespread use as preservatives. Their relevance lies in their ability to penetrate the skin and, in some cases, bind to estrogen receptors, suggesting a possible role as endocrine disruptors, also known as xenoestrogens. In simpler terms, some parabens may behave similarly to certain hormones in the body, sending signals that could influence how some cells respond. This mechanism is particularly relevant in the context of hormone-dependent neoplasms, such as breast cancer, although evidence in humans remains under debate. Nevertheless, the potential interaction with hormonal pathways makes these compounds an ongoing focus of research.

Another group of interest includes the so-called “formaldehyde donors,” compounds that release formaldehyde progressively under specific conditions. Formaldehyde is classified as a carcinogenic agent, and its mechanism of action includes the formation of cross-links between nitrogenous bases in DNA. In a way, these substances can “stick together” parts of DNA that should remain separate, making it more difficult for cells to accurately copy their genetic information. Additionally, it has been observed that formaldehyde can alter the expression of microRNAs, key molecules in gene regulation, suggesting a broader impact on proper cellular function. Although dermal exposure under normal conditions is considered limited, long-term accumulation remains an insufficiently characterized aspect.

Ethanolamines, such as triethanolamine (TEA), commonly used to regulate pH and stabilize formulations, represent another relevant group. These substances can affect cell membranes, which play a key role in maintaining cellular structure and function. Furthermore, under certain chemical conditions, they can lead to the formation of nitrosamines, compounds capable of directly damaging genetic material.

In the case of ethoxylated compounds, such as polyethylene glycols (PEGs), the main risk does not necessarily come from the ingredient itself, but from possible contaminants derived from their production process, such as ethylene oxide or 1,4-dioxane. Both have been associated with carcinogenic effects in different experimental models. It is not so much the “main ingredient” that is the issue, but rather small impurities that may be generated during manufacturing. This highlights the importance of considering not only the declared composition, but also the quality and control of industrial processes involved.

Additionally, the possible presence of heavy metals such as arsenic, lead, cadmium, and mercury, generally as contaminants, introduces an additional component of risk. These elements can accumulate in tissues, induce oxidative stress, and disrupt DNA repair mechanisms, creating a more “unstable” cellular environment and promoting damage that, over time, may not be properly repaired. Their persistence in the body and their capacity for bioaccumulation make them relevant factors in the analysis of long-term exposure.

It is important to note that cosmetic products marketed in the European Union are subject to strict regulations designed to ensure their safety under normal conditions of use. However, these evaluations are often based on individual exposures and do not always consider combined use scenarios or the cumulative effects resulting from the simultaneous application of multiple products. Likewise, interindividual variability in response to chemical substances represents an additional factor that may influence long-term susceptibility.

In this sense, the concept of lifetime cumulative exposure becomes particularly relevant. The simultaneous use of various products—foundation, concealer, powder, lipstick, mascara, among others—implies exposure to multiple compounds with different toxicological profiles. Although each may be considered safe within certain limits, their interaction and accumulation over time represent an area of research that is still under development.

Figure 1. Overview of common chemical groups in cosmetic products (parabens, formaldehyde-releasing compounds, ethanolamines, and PEGs) and their potential biological interactions, highlighting everyday exposure through makeup.

The available evidence suggests the need for a more comprehensive approach in evaluating these products, considering chronic exposure and its possible cumulative effects. However, more robust studies are still needed to more precisely characterize these effects under real-world conditions of use.

In this context, these findings should not be interpreted as a cause for alarm. Cosmetics currently on the market comply with existing regulatory standards, and their use is considered safe. The goal is to continue strengthening scientific evidence for a more complete and rigorous understanding in the long term.

Main reference:

Balwierz, R., Biernat, P., Jasińska-Balwierz, A., Siodłak, D., Kusakiewicz-Dawid, A., Kurek-Górecka, A., Olczyk, P., & Ochędzan-Siodłak, W. (2023). Potential Carcinogens in Makeup Cosmetics. International journal of environmental research and public health, 20(6), 4780. https://doi.org/10.3390/ijerph20064780 

Other references:

Chambers, E. S., & Vukmanovic-Stejic, M. (2020). Skin barrier immunity and ageing. Immunology, 160(2), 116–125. https://doi.org/10.1111/imm.13152 

Boer, M., Duchnik, E., Maleszka, R., & Marchlewicz, M. (2016). Structural and biophysical characteristics of human skin in maintaining proper epidermal barrier function. Postepy dermatologii i alergologii, 33(1), 1–5. https://doi.org/10.5114/pdia.2015.48037 

Magnano, G. C., Rui, F., & Larese Filon, F. (2021). Skin decontamination procedures against potential hazards substances exposure. Chemico-biological interactions, 344, 109481. https://doi.org/10.1016/j.cbi.2021.109481