Your thyroid is a small gland that controls how fast your body burns energy and grows. Scientists just reviewed hundreds of studies about chemicals in medicines, pollution, food, and everyday products that can interfere with how your thyroid works. They found that many different substances—from certain cancer drugs to heavy metals to some plant compounds—can damage your thyroid in various ways. This review explains how these chemicals cause problems and why protecting your thyroid from these substances matters for your overall health.

The Quick Take

  • What they studied: How different chemicals and substances from medicines, pollution, food, and products can damage the thyroid gland and disrupt how it makes and controls thyroid hormones.
  • Who participated: This was a review of existing research, not a study with human participants. Scientists analyzed hundreds of published studies about thyroid-disrupting chemicals.
  • Key finding: Many common chemicals—including some cancer medications, heavy metals like lead and mercury, industrial pollutants, and certain plant compounds—can interfere with thyroid function through different mechanisms, potentially causing thyroid problems.
  • What it means for you: Being aware of potential thyroid-disrupting chemicals in your environment and products may help you make informed choices about what you’re exposed to. However, this review doesn’t mean you should panic about everyday products—just be mindful of exposure to known harmful substances.

The Research Details

This was a systematic review, which means scientists searched through thousands of published research papers to find all the studies about chemicals that can damage the thyroid. They used three major scientific databases (PubMed, Scopus, and Web of Science) and also looked through the references of papers they found to make sure they didn’t miss anything important. The researchers organized all their findings using a new framework they created called the ‘3H framework’—which stands for how chemicals affect hormone-making, hormone balance, and overall human health.

By reviewing all the existing research together instead of looking at individual studies, scientists can see the bigger picture of how different chemicals affect the thyroid. This helps doctors and public health officials understand which substances are most dangerous and how to protect people from them.

This is a review of existing research rather than a new experiment, so it’s only as good as the studies it includes. The authors used established scientific databases and careful search methods, which is a strength. However, since different studies may have different quality levels, the conclusions are based on the overall pattern of evidence rather than one definitive proof.

What the Results Show

The review identified several categories of chemicals that can damage the thyroid: certain cancer medications (tyrosine kinase inhibitors and immune checkpoint inhibitors), heavy metals like lead and mercury, industrial chemicals used in manufacturing, and some plant compounds found in food. These chemicals interfere with the thyroid in multiple ways. Some block an important enzyme called thyroperoxidase that the thyroid needs to make hormones. Others prevent the thyroid from absorbing iodine, which is essential for thyroid hormone production. Still others affect how the body breaks down and uses thyroid hormones, or they trigger immune system attacks on thyroid tissue. The review also found that scientists are developing new computer-based methods to predict which chemicals are likely to damage the thyroid before they’re widely used.

The researchers emphasized that thyroid disruption doesn’t happen in isolation—it affects the entire hormone control system, including the brain structures (hypothalamus and pituitary gland) that tell the thyroid what to do. They also noted that the same chemical might affect different people differently depending on their genetics, age, and overall health status. The review suggests that understanding these mechanisms could help doctors better diagnose thyroid problems and help companies design safer medicines and products.

This review builds on decades of research showing that various chemicals can disrupt hormones. What’s new is the organized ‘3H framework’ that brings together information about how chemicals affect thyroid hormone production, hormone balance in the body, and human health outcomes. Previous research often looked at these aspects separately, so this review provides a more complete picture of how thyroid disruption works.

Since this is a review of other studies rather than original research, the conclusions depend on the quality and completeness of those studies. Some chemicals may have been studied more thoroughly than others. The review doesn’t provide specific risk levels for everyday exposure to these chemicals—it mainly explains the mechanisms of how they work. Additionally, most studies were done in laboratory settings or animals, so the real-world effects in humans may be different.

The Bottom Line

Based on this review, it’s reasonable to try to limit exposure to known thyroid-disrupting chemicals when practical—such as avoiding unnecessary heavy metal exposure, being cautious with certain medications, and eating a balanced diet. However, this doesn’t mean you need to make drastic life changes. If you’re taking a medication that might affect thyroid function, talk to your doctor rather than stopping it on your own. Regular thyroid screening may be helpful if you’re concerned about exposure to these chemicals.

This information is most relevant for people taking certain cancer medications, those living in areas with heavy pollution, workers in industries using these chemicals, and anyone with a family history of thyroid problems. Pregnant women and young children should be especially careful about exposure since thyroid function is critical during development. People without known risk factors don’t need to obsess over this, but general awareness is helpful.

Thyroid problems from chemical exposure can develop over weeks to months, or sometimes years depending on the chemical and exposure level. If you make changes to reduce exposure, it may take several months to see improvements in thyroid function, which is why regular check-ups are important.

Want to Apply This Research?

  • Track your thyroid symptoms weekly (energy levels, temperature sensitivity, weight changes, mood) and note any new exposures to medications or environmental factors. Rate each symptom on a scale of 1-10 to see patterns over time.
  • Set reminders to take thyroid medication at the same time daily if prescribed, log any new medications or supplements with your doctor’s approval, and record your location/activities when exposed to potential thyroid-disrupting chemicals to identify patterns.
  • Schedule thyroid blood tests (TSH and free T4) annually or as recommended by your doctor, maintain a log of symptoms and potential exposures, and track any changes in energy, weight, or temperature sensitivity over months to catch problems early.

This review summarizes scientific research about chemicals that may affect thyroid function. It is not medical advice. If you have concerns about your thyroid health, symptoms like fatigue, weight changes, or temperature sensitivity, or if you’re taking medications that might affect your thyroid, please consult with your healthcare provider. Do not stop taking prescribed medications without talking to your doctor first. This information is for educational purposes and should not replace professional medical evaluation and treatment.