We use cosmetics every day without giving it much thought. We trust that if they are on the market, they have passed sufficient controls. But few know that these controls are not designed to detect hormonal alterations, nor to evaluate real and continuous exposures. That's where the problems with endocrine disruptors begin.
🚫 Why cosmetic toxicology regulations are not sufficient to regulate endocrine disruptors
For decades, the safety of cosmetic products has been evaluated using the principles of classical toxicology. This approach has been useful for identifying clearly toxic substances and preventing obvious health risks. However, when we talk about endocrine disruptors, this model begins to show significant limitations.
Science has been warning for years that endocrine disruptors do not behave like traditional toxins. And yet, we continue to try to regulate them with tools designed for other types of risks. The result is a false sense of security.
Why does this happen?
1. Because classical toxicology does not explain how endocrine disruptors act
Traditional toxicology is based on a well-known idea: the dose makes the poison. According to this principle, a substance is only dangerous when a certain amount is exceeded, and below that threshold, it can be considered safe.
The problem is that this reasoning does not work for the hormonal system.
Hormones act at extremely low doses. Our body is designed to respond to minimal signals, not large amounts. Therefore, a substance does not need to be toxic to have a relevant effect: it just needs to mimic, block, or alter a hormonal signal.
Endocrine disruptors work precisely this way. They do not damage tissues or cause immediate toxicity. They act as false signals that confuse the body. In fact, many studies have shown that these substances can produce effects at very low doses, even lower than those used in regulatory tests, and that their response does not always increase with the dose. In some cases, low doses are the most active.
This makes classic safety parameters, such as NOAEL or safety margins, less useful in this context. These values are calculated by looking for visible effects at high doses, but endocrine effects can appear much earlier, without the evaluation system detecting them.
Therefore, a substance can meet all legal requirements and still interfere with the hormonal system under real conditions of use. It is not a problem of lack of data, but of using a model that does not fit the mechanism of action. Classical toxicology looks for damage; endocrine disruptors deprogram.
2. Because the timing of exposure is not taken into account
Another major blind spot in cosmetic regulations is that they do not consider when exposure occurs. Safety tests almost always focus on healthy adults and on short- or medium-term effects. This may be useful for detecting irritation or general toxicity, but not for evaluating endocrine risks.
The hormonal system is not equally sensitive throughout life. There are key stages—pregnancy, fetal development, childhood, and puberty—in which hormones not only regulate functions but also direct the development of the organism. During these critical windows, small alterations can have permanent consequences.
A substance that produces no visible effect in an adult can irreversibly alter hormonal development if exposure occurs during gestation or childhood. In these cases, the effect does not appear immediately. It may manifest years later, when it is no longer easily possible to link it to the original exposure.
Current cosmetic regulations do not evaluate this type of risk. They do not consider prenatal exposures, do not differentiate vulnerability based on life stage, and do not require specific studies on endocrine development. As a result, many potentially relevant effects are simply not sought.
3. Because long-term and transgenerational effects are ignored
Toxicological evaluation in cosmetics is designed to detect relatively rapid and measurable effects. If a substance, by itself, is below its "safe" limit, it is considered risk-free.
However, endocrine disruptors do not always act that way.
Hormonal interference can initiate biological processes that remain silent for years and only manifest later, in the form of reproductive problems, thyroid alterations, metabolic disorders, or other hormone-dependent diseases. There are increasingly more studies linking early exposures to pathologies that appear in adulthood.
In addition, many endocrine disruptors can cause epigenetic changes, meaning modifications in the way genes are expressed without altering DNA. These changes can accompany the person throughout their life and, in some cases, even be transmitted to future generations.
This type of effect is completely outside the scope of the current evaluation framework. Regulatory tests are not designed to observe long-term consequences or to analyze possible impacts on offspring. The regulatory model falls short when the damage is not immediate.
4. Because isolated substances are evaluated, not real exposure
In cosmetic regulations, each ingredient is evaluated individually. If a substance, by itself, is below its "safe" limit, it is considered to pose no risk.
But this situation does not reflect reality.
In daily life, we use several cosmetic products a day: gel, shampoo, cream, deodorant, makeup... Each one contains multiple ingredients. Real exposure is simultaneous and cumulative, not isolated.
When several substances with hormonal activity act at the same time, they can add up or enhance their effects, even if each one is below its individual limit. This phenomenon, known as the cocktail effect, is well documented scientifically, but it is hardly taken into account in cosmetic regulation.
The current framework does not evaluate combined exposure or consider that several endocrine disruptors can act on the same hormonal systems. As a result, the real risk can be very different from what regulatory studies describe.
Conclusion: the problem is not the lack of regulations, but the approach
These four points make it clear that the problem is not the absence of tests or a bad application of regulations, but the conceptual model on which they are based. Classical toxicology is not designed to detect hormonal interferences at low doses, does not consider the timing of exposure, ignores effects that appear years later, and evaluates substances in isolation, far from real exposure.
Applying this approach to endocrine disruptors inevitably leads to underestimating the risk. As long as cosmetic regulation does not incorporate advances in endocrinology and a more realistic view of how we are exposed to these substances, there will continue to be a gap between the theoretical safety established by regulations and the actual long-term health protection.
