Endocrine disruptors are compounds capable of altering the production, transport, metabolism, or action of hormones. They are found in various everyday products, such as plastic containers, the inner linings of cans, food packaging, some cosmetics, and synthetic fabrics, among others.
From a biological standpoint, they act as true “hackers” of the hormonal system.
They enter the body through ingestion, inhalation, or absorption through the skin. Some have a structure similar to that of natural hormones and trigger inappropriate or exaggerated responses. Others act like a faulty key: They bind to cellular receptors and block or reduce the action of hormones produced by the body.
Among the organs most vulnerable to the effects of endocrine disruptors is the thyroid gland. It produces hormones that regulate metabolism, energy expenditure, body temperature, neurological development, and various cardiovascular functions. Since its proper functioning depends on a delicate hormonal balance, even small changes can affect different organs and stages of life.
Once in the body, endocrine disruptors can interfere with thyroid function in several ways. They can hinder the uptake of iodine, which is essential for producing the hormones T3 and T4, or alter the activity of enzymes involved in their production. They can also affect how thyroid hormones are transported, metabolized and eliminated, or interfere with their ability to bind to cellular receptors. For this reason, the thyroid has become one of the main focuses of research on the impacts of these substances.
However, the effects of this interference are not always immediately noticeable, as thyroid function is also influenced by genetic factors, age, iodine availability, autoimmune diseases, and other environmental exposures. Nevertheless, a growing number of studies, reviews, and meta-analyses point to an association between prolonged exposure to certain endocrine disruptors and changes in thyroid stimulating hormone (TSH), T3, and T4 levels, as well as increased susceptibility to thyroid dysfunction.
Studies also indicate that the severity of the effects varies depending on the substance, the dose, the duration of exposure, and the characteristics of the populations studied. The evidence is most consistent for compounds such as bisphenols, phthalates, “forever chemicals” like perfluoroalkyl and polyfluoroalkyl substances (PFAS), and perchlorates.
The effect of combined exposures
Published in 2025, a recent review highlights that establishing causal relationships between endocrine disruptors and specific diseases remains a challenge, mainly because exposure occurs continuously and simultaneously to mixtures of various compounds.
Understanding how these combined exposures interact within the body and influence disease risk has become one of the top priorities in environmental endocrinology research. Considering the totality of exposures brings studies closer to the real-world conditions in which we live and allows for a better understanding of how small hormonal disruptions, repeated continuously over years, can produce clinically relevant effects
The potential effects of these substances are not limited to the thyroid. There is evidence of changes in male fertility and an increased risk of obesity, metabolic syndrome, and type 2 diabetes. In addition, scientists are investigating the relationship between these compounds and certain hormone-dependent tumors, such as breast, prostate, and thyroid cancers. Again, this is a body of evolving evidence, in a context where various environmental and behavioral factors also influence the development of these diseases.
This context helps explain why international institutions have been advocating for an approach based on the precautionary principle. This does not mean that any contact with these substances will inevitably lead to the development of diseases, but rather that reducing unnecessary exposure can benefit public health, especially given the widespread presence of these compounds in the environment.
Completely eliminating exposure is still far from possible. However, certain choices can help reduce it.
Whenever possible, it is advisable to:
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Prioritize fresh foods over ultra-processed ones.
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Avoid heating food in plastic containers.
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Choose glass or stainless steel for storing food and beverages.
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Reduce the use of products with synthetic fragrances.
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Replace plastic containers with glass ones.
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Check the ingredients of frequently used cosmetics and personal care products.
These measures, however, have limited scope. Reducing exposure depends on regulation, environmental monitoring, ongoing review of safety limits, and incentives for the development of safer materials. This is a challenge that involves governments, industry, the scientific community, and consumers.
A growing list of threats
In recent decades, international organizations such as the World Health Organization (WHO), the United Nations Environment Programme (UNEP), and the Organization for Economic Cooperation and Development (OECD) have begun to monitor studies on the effects of endocrine disruptors and to develop strategies.
To date, more than 800 substances have been classified as potential endocrine disruptors. Among the best known are bisphenols, used in the manufacture of rigid plastics and in the inner lining of cans; phthalates, used to make PVC flexible and found in packaging, fragrances, and some cosmetics; PFAS, used in some nonstick, water-resistant, and grease-resistant materials; as well as dioxins, perchlorates, and other persistent pollutants. Microplastics have also been added to this list after being identified in drinking water, food, and even the human body.
The invisibility of these compounds is perhaps the greatest challenge. They are part of the daily lives of virtually everyone and, in most cases, do not produce immediate or easily noticeable effects. Investigating how they affect the body is an important step toward guiding public policy, improving regulation, and ensuring more informed choices.
This article was originally published on The Conversation. Read the original article.
