How Environmental Toxins Harm the Thyroid

The prevalence of thyroid disease has skyrocketed within the past few decades. According to the American Thyroid Association, an estimated 20 million Americans have some form of thyroid disease. (1) This alarming trend begs the question—what is responsible for the epidemic of thyroid dysfunction? A growing body of research indicates that exposure to environmental toxins is a key piece of the thyroid disease puzzle. Read on to learn about the types of toxins that are harmful to the thyroid and how you can help your patients minimize their toxic exposures and protect their thyroid health.

Can chemicals cause hypothyroidism

What Types of Toxins Affect the Thyroid?

The thyroid is a small but vitally important endocrine gland located in the base of the neck. It releases a steady stream of hormones that are intrinsically involved in the regulation of metabolism, as well as endocrine, cardiovascular, neurological, and immune function. Despite the powerful role the thyroid plays in the body, it is quite susceptible to damage from exogenous influences such as environmental toxins. This is due in part to the fact that several categories of environmental toxins bear a structural similarity to thyroid hormones. In addition, the thyroid gland has a naturally high affinity for halogens and metals. While this affinity is intended to draw iodine (a halogen) and selenium (a metalloid) into the thyroid for the production and metabolism of thyroid hormones, it can also lead to the accumulation of harmful halogens and metals within the gland. The types of toxins that affect the thyroid are thus primarily substances that mimic thyroid hormone structure, contain halogens, or are heavy metals. These toxins can be divided into four main groups based on their source: industrial chemicals, pesticides and herbicides, toxins in consumer goods, and heavy metals.

Industrial Chemicals Impair Thyroid Function

Environmental pollution is increasing at a worrying rate worldwide. Three of the most common industrial pollutants are perchlorate, polychlorinated biphenyls (PCBs), and dioxin. These three pollutants have been found to significantly disrupt thyroid function.

Perchlorate is a highly reactive compound that is primarily man-made; small amounts of perchlorate occur naturally in the soil of arid environments, but the contribution of these to environmental contamination is minimal. Perchlorate is widely used in military applications, including rocket fuel and explosives, as well as in the production of leather, rubber, paint, and batteries. Perchlorate accumulates in surface water, groundwater, soil, and food grown in contaminated soil. Drinking water, grains, produce, and dairy products from animals raised on contaminated soil may contain elevated levels of perchlorate. (2)

The thyroid gland is the primary target of perchlorate toxicity in humans. (3) Urinary perchlorate levels, which are representative of the body’s burden of perchlorate, are associated with decreased thyroxine (T4) and increased thyroid-stimulating hormone (TSH). (4) Research also indicates that perchlorate can disrupt thyroid function at both high and low doses, overturning the commonly held belief in toxicology that “the dose makes the poison.” (5) Perchlorate contains chlorine, which is a halogen with the same ionic charge as iodine. Perchlorate thus disrupts thyroid function by competing with iodide, an essential component of T4, for uptake by the thyroid gland. This results in reduced thyroid hormone production. Research indicates that low iodine increases one’s vulnerability to the effects of perchlorate. Conversely, a greater intake of iodine may help protect the thyroid from the disruptive effects of perchlorate. (6, 7)

Polychlorinated biphenyls, or PCBs, are another group of industrial toxins that have harmful effects on the thyroid. These man-made chemicals are resistant to temperature and pressure and have thus been used in electrical equipment, as lubricants, and in the production of plastics, adhesives, and paints. Despite being banned in the United States in 1979, PCBs continue to resist degradation and persist in the environment. Research indicates that PCBs disrupt thyroid function through a variety of mechanisms. They suppress the production of the thyroid hormone receptor, reducing the number of receptors with which thyroid hormone can bind in the body. (8) PCBs bind to thyroid transport proteins, decreasing circulating T4, and impair liver enzymes responsible for converting T4 to T3. (9, 10, 11) PCBs have also been found to raise thyroid antibody levels and promote enlargement of the thyroid gland. (12, 13) The presence of chlorine (a halogen) in PCBs, as well as the structural similarity between PCBs and thyroid hormone, helps to explain the broad spectrum of effects that PCBs have on the thyroid.

Like perchlorate and PCBs, dioxin is a byproduct of manufacturing processes, including pesticide and plastic production. Dioxin exposure at levels considered standard in the United States has been associated with decreased T4 and reduced thyroid function, with females more significantly affected than males. (14) Dioxin mimics thyroid hormone structure and appears to decrease T4 by binding to cell receptors that enhance glucuronidation, a biochemical process that facilitates the excretion of hormones from the body.

Pesticides and Herbicides Induce Hypothyroidism

Pesticides and herbicides are another group of highly prevalent environmental toxins that adversely affect thyroid function. Exposure to organochlorine pesticides, the herbicide paraquat, and the fungicides benomyl and maneb/mancozeb has been associated with an increased incidence of hypothyroidism in women. (15) The use of a wide variety of other pesticides, including organophosphates and carbamates, has been associated with hypothyroidism in men. (16) Pesticides and herbicides disrupt thyroid function by interfering with thyroid hormone gene expression, inhibiting the thyroid’s uptake of iodine, binding to thyroid hormone transport proteins, reducing cellular uptake of thyroid hormone, and increasing thyroid hormone clearance from the body. (17, 18)

Toxins in Common Household Products Harm the Thyroid

Ideally, a person’s home should be their haven, a safe retreat from the outside world. However, modern-day homes can unfortunately contain a plethora of toxins, some of which have a significant impact on the thyroid. Flame retardants, known in the scientific literature as polybrominated diphenyl ethers (PBDEs), are one class of toxins found in consumer goods that may harm the thyroid. They are found in items such as computer and TV screens, furniture, carpet padding, and synthetic textiles. PBDEs contain bromine, a halogen, and thus have a predilection for the thyroid. Flame retardants disrupt thyroid function by mimicking the structure of thyroid hormone; they displace T4 from thyroid hormone-binding proteins, preventing T4 from being transported in the blood. They also compete with T4 for thyroid hormone receptor binding sites and disrupt estrogen activity. This unique interaction may make postmenopausal women especially susceptible to the thyroid-disrupting effects of PBDEs. (19, 20)

Plastics are ubiquitous in our homes, appearing in items such as food storage containers, water bottles, personal care products, and children’s toys. Many plasticizers, such as BPA and phthalates, mimic the structures of natural hormones and thus have a disruptive effect on the endocrine system, including thyroid function. Bisphenol A (BPA), found in food-can linings and plastic bottles, has been found to alter thyroid structure and act as an antagonist to T3 at thyroid hormone receptors. (21, 22) Phthalates, used in vinyl flooring, adhesives, plastics, and as emollients in personal care products, also disrupt thyroid function by inhibiting the binding of thyroid hormone to its receptors. (23)

Finally, two more common household toxins that disrupt thyroid function are the antibacterial chemical triclosan, found in products such as liquid hand soap, and PFOA, used in non-stick cookware and stain-resistant fabrics. Animal studies suggest that triclosan and PFOA decrease T4, ultimately lowering thyroid function. (24, 25, 26)

Heavy Metals: Not a Friend to the Thyroid

Heavy metals are pervasive in our environment, and research continues to emerge demonstrating their harmful effects on human health. The heavy metals with the most significant impact on thyroid function are cadmium, lead, mercury, and aluminum.

Cadmium is a heavy metal that is released into the environment through mining and smelting and is also ubiquitous in phosphate fertilizers, sewage sludge, batteries, pigments, and plastics. Chronic cadmium exposure has been found to precipitate multinodular goiter, reduce the secretion of thyroglobulin, and initiate thyroid cell hyperplasia, which may lead to thyroid cancer. (27, 28)

The contamination of our environment with lead, another toxic heavy metal, has increased substantially due to industrialization, mining, and the previous use of lead in gasoline. Lead is also found in paint in older homes, inexpensive metal jewelry, and children’s toys. Occupational exposure to lead has been associated with depressed thyroid function and elevated TSH. (29) Lead may alter thyroid function by causing deiodination of T4. While it is not clear whether current lead exposure levels experienced by the U.S. population adversely affect thyroid function, it is important that we remain aware of the potential thyroid health risks posed by this heavy metal. (30)

Read more  Hashimoto's Disease and Blood Sugar Imbalance

Finally, mercury and aluminum exposure are inversely associated with thyroid hormone levels. Common sources of mercury exposure include dental amalgams, seafood, and pollution from coal-burning power plants. Sources of aluminum include antacids, body care products such as deodorant, food additives, and aluminum-based cookware. Mercury accumulates in the thyroid and reduces iodide uptake, thus inhibiting thyroid hormone production. (31) Animal studies indicate that aluminum oxidatively damages the thyroid, which subsequently affects iodide uptake and thyroid hormone production. (32) Aluminum also triggers an immune response that can lead to the production of antibodies, some of which may target the thyroid. (33)

Tips for Reducing Exposure to Thyroid-Disrupting Toxins

While environmental toxins are ubiquitous, there are many ways in which we can help our patients reduce their exposure to these chemicals and ultimately protect and improve their thyroid health.

  • Make sure your patients have optimal levels of iodine and selenium. Optimal iodine and selenium intake has been found to attenuate the toxic effects that heavy metals and perchlorate can have on the thyroid.
  • Encourage your patients to purchase a high-quality water filter for their drinking and bathing water; municipal tap water can be a significant source of toxins. However, a water pitcher filter is not enough if one hopes to remove as many toxins as possible. Reverse-osmosis filters, on the other hand, have been found to effectively remove perchlorate, pesticides, PCBs, plastics, and a wide variety of heavy metals.
  • Recommend that your patients eat organic food as much as possible. This will help them avoid excessive pesticide and herbicide exposure. They should also be encouraged to cease using pesticides in their homes and yards.
  • Encourage your patients to stop using synthetic antibacterial products and to limit their use of plastics at home. If they still choose to use some plastic products, recommend that they look for “BPA-free” options. However, keep in mind that BPA-free products may still contain other bisphenol derivatives with potential thyroid-disrupting effects, so it really may be best to entirely avoid drinking from or storing food in plastic containers.
  • Recommend that your patients stop using non-stick cookware. PFOA from non-stick cookware can leach into food and is subsequently ingested. Suggest that they use stainless steel or enameled cast iron cookware instead.

If you are interested in learning more about the health impacts of environmental toxins and what factors influence one’s susceptibility to toxins, check out my previous article “Environmental Toxins: The Elephant in the Room?” For more information on how you can help your patients reduce their toxic exposures, check out my article “Environmental Toxins: Steps for Decreasing Exposure and Increasing Detoxification.”

— Update: 06-01-2023 — found an additional article How Common Chemicals Are Harming Your Thyroid from the website for the keyword can chemicals cause hypothyroidism.

Our endocrine system is made up of glands that produce and secrete hormones that regulate many of the body’s functions, including growth and development, metabolism, electrolyte balances, and reproduction.

The hypothalamus is a portion of the brain that links the nervous system to the endocrine system via the pituitary gland. The pituitary gland, sometimes called the “master gland,” controls the function of numerous other targeted endocrine glands. These include the adrenal glands which produce cortisol; the gonads which produce sex hormones; the thyroid which produces thyroid hormone; the parathyroid which produces parathyroid hormone; and the pancreas which produces insulin and glucagon.

Because many of these hormones are part of a hormonal cascade that is responsible for almost every cell and organ in the body, a disorder in any of these glands may cause a major decline in overall health. 

What are endocrine disruptors?

Endocrine disruptors are chemicals that interfere with the hormone systems and may cause adverse developmental, reproductive, neurological, and immunological effects. Often man-made, these chemicals can be found in everyday products that we use and ingest, including plastic bottles, detergents, food, toys, cosmetics, and pesticides. The National Institute of Environmental Health Sciences suggests that these products may be resulting in reduced fertility and increased progression of some diseases, including obesity, diabetes, endometriosis, and some cancers. 

How can the normal communication of the endocrine system be disrupted?

Chemical substances can disrupt the normal communication of the endocrine systems in three different ways:

  1. They bind to thyroid receptors and mimic the natural hormone. The disruptor may send an ill-timed or stronger signal than the natural hormone.

  1. They bind to thyroid receptors and prevent the correct hormone from binding. This means that the normal sign does not occur, affecting how the body responds.

  1. They interfere or block the ways in which natural hormones and receptors are made or managed.

If these substances affect the normal rhythm of the endocrine systems, then increased or decreased amounts of hormones may be produced. 

Simply put, endocrine disruptors cause hormone imbalance. So, if we are constantly exposed to these chemicals, we can’t completely heal from thyroid disorders. It’s impossible to remove all the offenders, but with some effort, it may be possible to reduce our exposure.

Where are we exposed to endocrine disruptors?

All of the consumer products that we inhale, ingest, and apply to our bodies put us in contact with hundreds of disruptors each day. When we equip ourselves with knowledge about what products contain which chemicals, we can make informed lifestyle changes and choices.

Some of the top ways that we expose ourselves to disruptors include, but are not limited to:

Personal Care Products

Many cosmetics, lotions, hair care products, and toothpaste brands contain phthalates, triclosan and other harmful chemicals that affect the endocrine system by altering our hormones and raising estrogen to unhealthy levels.

Canned Food and Plastic Containers

Most companies have removed Bisphenol-A (BPA) from their packaging, but there are still some products that contain this endocrine disruptor. BPA acts like estrogen in the body and raises estrogen levels in both men and women. 

Conventional Produce

Conventional produce is sprayed with numerous pesticides and herbicides. Produce that have soft edible skin are the worst offenders because not only does the chemicals leach into the produce, the skins are generally consumed as well.  


Chlorine removes iodine from our cells which is particularly harmful to the thyroid because most people already suffer from iodine deficiency and thyroid tissue requires a large amount of iodine. In addition, studies have shown a link between chlorine exposure and low testosterone levels. In general, it is best to avoid chlorine as much as possible. 

Cleaning Products

Aerosol cans, bleach, air fresheners, and other cleaning products are filled with multiple toxic chemicals that we breathe and are absorbed through our skin. In addition to being endocrine disruptors, they can also cause respiratory illness and headaches.  

How to avoid endocrine disruptors:

It may be difficult to avoid common chemicals entirely but, equipped with the proper knowledge, you can begin to remove some of the worst offenders from your daily interactions. 

  1. Replace personal care products with natural or homemade varieties. Might we suggest The Detox Market? They only carry products with pure ingredients and cruelty-free formulas. (You can even try before you buy with a sample bag!)

  1. Buy food and beverages that are BPA-free. Better yet, choose options that are packaged in glass containers! Also, it’s suggested to avoid warming food inside plastic containers because the heat allows the chemical to leech into the food or beverage.

  1. Purchase organic produce whenever possible to avoid pesticides and herbicides, especially in produce where the skin is consumed. Another great shop-at-home option may be Thrive Market, an online membership-based retailer offering natural and organic food products at reduced costs. (You can even shop by diet preferences – keto, paleo, gluten-free, etc. – which is super helpful to those who eat a particular kind of way to support their thyroid health.)

  1. Use a water filtration system to avoid drinking chlorinated water. Whole house water filtration is also a great investment because it will filter all tap water including water that used for bathing. If you’re considering getting a pool, then a saltwater system may be the best choice!

  1. Buy natural cleaning products with ingredients that you recognize as safe. This Safer Choice options guide may be helpful when choosing store-bought cleaning supplies. Consider using household products like vinegar and baking soda to clean your home. Adding a little lemon or lavender essential oil will help achieve a nice citrus aroma that will replace the toxic fragrances in typical cleaning supplies.

Understanding how the endocrine system works is one of the first steps in understanding thyroid disorders. This awareness of how to eliminate endocrine disruptors from your life will greatly help as you manage your thyroid condition. Having a care team that specializes in thyroid health is also essential as you journey to feeling your best.

Editor's Note: Paloma Health is not affiliated with any of the companies or products shared on this page. We simply share resources that we believe may be helpful to those struggling with a thyroid condition.

Read more  SHBG Lab Test Guide – What to do About High Levels, Low levels & More

Related articles:

  • 4 Ways Conventional Deodorants May Harm Your Hormone Health
  • Does Sunscreen Affect Your Thyroid Gland?
  • Does Bug Spray Affect Your Thyroid Gland?

— Update: 06-01-2023 — found an additional article 6 Toxins That Threaten Thyroid Health from the website for the keyword can chemicals cause hypothyroidism.

Your thyroid gland is a part of the endocrine system and is responsible for producing several hormones that help manage energy levels, metabolism, and much more. When the thyroid is healthy and working properly, the systems in your body work together seamlessly. When the thyroid is exposed to toxins, it can begin to malfunction and cause a number of health issues. Let’s read here 6 toxins that threaten thyroid health!

Toxins Harming Your Thyroid Health

Toxins are found throughout our environment. They can be found in our food supply, our water supply, our household products, and our personal care items. It is almost impossible to eliminate all exposure to toxins; however, you can limit your exposure, thus minimizing the risk of experiencing health issues. You should use an iodine supplement and limit your exposure to the following six toxins that harm the thyroid gland.

Can chemicals cause hypothyroidism

Heavy Metals – Most people have heard about the dangers of lead; however, there are numerous other heavy metals that can negatively impact the thyroid gland. These include aluminum, cadmium, lead, and mercury.

In the past, lead was used in paint and gasoline. Cheap jewelry and children’s toys can contain lead. Cadmium is found in plastics, certain fertilizers, pigments, sewage, and batteries. Aluminum and mercury disrupt iodine uptake. Mercury can be found in dental fillings and seafood. Aluminum is used in cookware, vaccines, deodorant, antacids, and certain food additives. As you can see, in today’s world, we are constantly exposed to heavy metals in our daily life.

Herbicides and Pesticides – Herbicides and pesticides are used in industrial farming and are hard to avoid. One way to reduce the risk of consuming foods that contain pesticides and herbicides is to choose organic foods. Unfortunately, because of runoff, herbicides and pesticides can enter our water supply.

Herbicides and pesticides reduce the thyroid’s ability to use iodine. These chemicals have been associated with an increased risk of hypothyroidism. Pesticides and herbicides cause excess thyroid hormone to be removed from the body. The more herbicides and pesticides that you are exposed to, the higher your risk of developing thyroid issues.

Flame Retardants – The chemical used to reduce the flammability of fabrics, clothing, furniture, and carpeting can cause thyroid dysregulation. Flame retardants contain bromine (halogen) which mimic thyroid hormone and are transported in the blood competing to attach to thyroid hormone receptors. Bromine, the chemical found in flame retardants, can be found in pool cleaners, pasta, drinks, and everything in between.

BPA – BPA is an industrial chemical that is used during the manufacturing of plastics and epoxy resins. BPA is used in commonly used food storage containers and beverage containers like water bottles. BPA is also used in the epoxy used to line metal food cans, water supply lines, and bottle caps. Finally, BPA can be found in certain dental composites and sealants.

BPA exposure can cause a plethora of health problems. In addition to damaging the thyroid gland, BPA exposure can cause cardiovascular problems (hypertension, heart attack, peripheral artery disease, and coronary artery disease), reproductive disorders (infertility, libido, and impotence), and an increased risk of breast and prostate cancer. In addition to this, BPA can increase the risk of type 2 diabetes, weight gain, and an increased risk of asthma and wheezing.

Fluoride – Many people are surprised to learn that fluoride can disrupt the thyroid gland. Although fluoride is added to water to prevent cavities, it can damage your thyroid health. Research has shown that consuming as little as two to five milligrams of fluoride over a few months can lower thyroid functions. Unfortunately, that is about the amount of fluoride that you drink in fluoridated water each day. Therefore, drinking fluoridated water could possibly lower your thyroid function.

PFCs – PFCs (perfluorinated chemicals) disrupt thyroid function, especially in women. PFCs are used in the manufacturing process of several items, including takeout containers, pizza boxes, and even certain mattresses. PFC is an endocrine disruptor that takes the body a long time to break down. Although PFCs are being phased out in the United States, an imported product could still contain PFCs.

Toxicity Questionnaire Can chemicals cause hypothyroidism

The Toxicity Screening Questionnaire helps identify symptoms that are useful to detect underlying causes of illnesses.

Click Here for the Toxicity Questionnaire

Reduce Your Exposure to Toxins

Can chemicals cause hypothyroidism

Although it is practically impossible to avoid exposure to all toxins, you can help minimize your exposure with the following tips. As you reduce toxin exposure, your thyroid will begin functioning better. Follow these tips to reduce exposure and improve your thyroid health.

  • Avoid using herbicides and pesticides in your home and yard
  • Choose organic foods when possible
  • Detoxify the body using a proven detoxification program
  • Increase iodine and selenium intake
  • Limit plastic usage
  • Avoid using nonstick cookware
  • Avoid using antibacterial products
  • Use a water filter for your drinking and bathwater

To help protect your health and improve your well-being, you need to ensure that your thyroid is as healthy as possible. Eat a well-rounded diet filled with organic fruits and vegetables and opt for filtered, purified water.

To ensure your thyroid remains healthy, it is advisable to visit a thyroid specialist to help reduce toxin exposure and detoxify your body.

— Update: 06-01-2023 — found an additional article Environmental Toxins and their Role in Thyroid Diseases from the website for the keyword can chemicals cause hypothyroidism.

Thyroid diseases are more common than you may believe and affect millions of people worldwide. Recently, thyroid diseases have been increasing, and this has motivated researchers to investigate the cause. They found that several environmental toxins are at least contributing to thyroid diseases and should be avoided to protect thyroid health.

This guide outlines the information most crucial to maintaining thyroid health and minimizing environmental toxin exposure including:

  • Why the thyroid is at risk for damage
  • How different environmental toxins affect the thyroid
  • Thyroid diseases induced by environmental toxins
  • Nine steps that protect the thyroid from environmental damage

Why the Thyroid Is at Risk of Damage

The thyroid gland is located at the base of the neck overlying the trachea (windpipe) and plays a vital role in the endocrine system. Despite its small size, the thyroid is one of the largest endocrine glands.

Following stimulation by thyroid-stimulating hormone (TSH) produced by the pituitary gland, the thyroid releases the hormone, thyroxine (T4), which must be converted by the liver into an active form called triiodothyronine (T3). T3 assists in regulating cardiovascular and neurological function along with supporting immunity, metabolism, and energy levels.

It is not so much the size of the thyroid that makes it susceptible to damage; it’s the structures of the hormones it produces. The thyroid requires iodine and selenium to produce its hormones, and these elements are chemically attracted to the structure of thyroid hormones (T3 or T4).  This chemical attraction is referred to as “affinity,” and it can also occur between other substances and thyroid hormones. Thus, many environmental toxins with structures similar to thyroid hormones are mistaken for iodine and selenium and accumulate in the thyroid gland.

How Different Environmental Toxins Affect the Thyroid

Environmental toxins that mirror thyroid hormone structure and invade the thyroid gland can be categorized as:

  • Heavy metals
  • Household toxins
  • Industrial chemicals and
  • Agricultural agents

Heavy Metals

While heavy metals are abundant in the environment, four specific heavy metals damage the thyroid the most. Those heavy metals are aluminum, cadmium, lead, and mercury.

Commonly found in toiletries like deodorant, over-the-counter medications like antacids, food additives, cookware, and vaccines, aluminum oxidizes the thyroid, inhibits iodide uptake, limits thyroid hormone production, and can mislead the immune system to attack the thyroid, as seen in autoimmune disease.

Cadmium is released via mining and smelting activities and is present in batteries, pigments, plastics, sewage, and phosphate-based fertilizers. Cadmium triggers thyroid enlargement, produces multinodular goiters of the thyroid, reduces thyroglobulin secretion, and can induce thyroid cancer.

One of the earliest heavy metals recognized for its toxicity, Lead remains high in the environment thanks to its use in the paint used in old housing, some metal jewelry, children’s toys, mining, and other forms of industrialization. Lead exposure in work environments alone has been linked to reduced thyroid function and increased levels of thyroid-stimulating hormone (TSH). Mercury, found in seafood, dental amalgams, and pollution produced by coal-burning power plants, lowers iodide uptake in the thyroid and prevents thyroid hormone production.

Household Toxins

Polybrominated diphenyl ethers (PBDEs), more commonly referred to as flame retardants, populate many areas of the modern-day home such as furniture, carpet padding, clothing made of synthetic materials, and the screens of electronic devices. PBDEs imitate thyroid hormone structure allowing PBDEs to bind to a particular class of proteins called transporters that T4 usually binds to, thereby blocking T4 from being transported in the blood. This activity disturbs estrogen function making postmenopausal women especially vulnerable to PBDEs.

Read more  6 Toxins That Threaten Thyroid Health

Bisphenol A (BPA) and phthalates, ingredients used to make plastic for water bottles, children’s toys, and food storage containers, imitate the structures of other hormones found naturally in the body and disrupt the entire endocrine system along with the thyroid.BPA changes the structure of the thyroid gland and inhibits T3 from binding to another class of proteins called receptors which T3 uses to produce changes in the body while phthalates also inhibit T3 from binding to its receptors. Thyroid function is also diminished by triclosan, an antibacterial agent found in some liquid hand soaps, and perfluorooctanoic acid, or PFOA, an agent used in stain-resistant fabrics, food wrappers, and non-stick cookware.

Industrial Chemicals

The most prevalent industrial chemicals are dioxin, perchlorate, perfluorinated chemicals, or PFCs, and polychlorinated biphenyls, or PCBs. All four of these pollutants negatively affect thyroid function. Dioxin, a byproduct of pesticide production, plastic making, and other manufacturing processes, reduces thyroid function by mimicking thyroid hormone structure and decreasing T4 levels. These effects arise even at standard dioxin levels; that is, low levels of dioxin that exist in the environment, yet are considered unavoidable.

Small concentrations of perchlorate arise naturally in the soil of arid regions, but the high levels polluting the environment come from applications involving the development of airbags, batteries, fireworks, leather, paint, jet/rocket fuel, and rubber. From there, perchlorate seeps into surface water, groundwater, drinking water, soil, and ultimately food grown in the ground. Once in the body, perchlorate lowers T4 levels, competes with iodide for uptake into the thyroid gland, and reduces thyroid hormone production. Even low levels of perchlorate toxicity can produce these effects yet consuming more iodine may protect the thyroid from perchlorate.

The use of PFCs has been on the decline, however, from mattresses and detergents to food packaging and fire extinguishers, many imported goods still contain PFCs. PFCs disrupt overall thyroid function by either increasing thyroid hormone production to dangerously high levels or decreasing thyroid hormone production to dangerously low levels. These effects appear to depend on gender, as women with PFC toxicity tend to develop hyperthyroidism while men with PFC toxicity tend to develop hypothyroidism.

For their ability to resist pressure and temperature, PCBs are widely used as lubricants, in electrical equipment, and for adhesive, paint, or plastic production.

PCBs disturb thyroid function by:

  1. reducing the number of receptors available for T3 to bind to
  2. decreasing the amount of T4 circulating in the bloodstream (T4 is needed for conversion into T3), and
  3. preventing liver enzymes from converting T4 into T3.

Other studies have found that PCBs enlarge the thyroid and can increase TSH levels to the point of making the body resistant to thyroid hormones. Again, PCBs achieve these effects by copying the structure of thyroid hormones.

Agricultural Agents

Perhaps the first culprits to come to mind in discussions of environmental toxins; pesticides, herbicides, and fungicides weaken thyroid function to the point of causing hypothyroidism or “low thyroid.” Hypothyroidism induced by agricultural agents is typically seen in women overexposed to pesticides containing organochlorine, paraquat herbicide, benomyl fungicide, or maneb/mancozeb fungicide. Men with hypothyroidism induced by agricultural agents are usually overexposed to organophosphates, carbamates, or other pesticides. Agricultural agents wreck thyroid function by altering thyroid hormone gene expression, preventing the uptake of iodine into the thyroid, blocking thyroid hormone from binding to its transport proteins, lowering the absorption of thyroid hormone into thyroid cells, and promoting thyroid hormone removal from the body.

Thyroid Diseases Induced by Environmental Toxins

Among all heavy metal toxins, chronic toxicity with aluminum, lead, and mercury can further damage the thyroid by recruiting antibodies to attack the thyroid. This process contributes to the development of autoimmune thyroid diseases (AITD), such as Graves’ disease and Hashimoto’s thyroiditis. Research has yet to determine the physiological mechanisms by which AITD manifests; however, two causes have been identified—environmental toxicity and genetic predisposition.

Because the production of antibodies against the thyroid does not always escalate into AITD, AITD arises in approximately only 5% of individuals and those individuals are more often women. Studies explain the reason for this is that females’ immune systems are more reactive than males’ even in other species. This evolutionary feature helps females fight off disease more effectively, most likely to ensure reproduction for healthy population growth. However, in humans, this places the woman’s thyroid at even greater risk of AITD. Men are not entirely excluded from AITH with their less reactive immune systems though, as scientists have found that contracting any of the following viruses enhances the incidence of Thyroid Diseases:

  • Acquired Immunodeficiency Syndrome (AIDS)
  • Enterovirus
  • Epstein-Barr Virus
  • Hepatitis C (HCV)
  • Herpes Simplex Virus
  • Human Immunodeficiency Virus (HIV)
  • Human Parvovirus B19 (EVB19)
  • Human T-cell Lymphotropic Virus-1
  • Mumps
  • Rubella

The Most Common Thyroid Diseases

Hashimoto Thyroiditis, a relative to chronic fatigue syndrome and fibromyalgia, affects mostly women and tops the list of conditions responsible for low thyroid (hypothyroidism). Hashimoto’s is so common that 97% of individuals taking thyroid medication are believed to have the disease but are not diagnosed. People with Hashimoto’s often express feeling like they are getting older because they experience symptoms such as anxiety, brain fog, cold intolerance, depression, fatigue, heart palpitations, hair loss, loose bowels, and an inability to lose weight. All these symptoms indicate a dysfunctional thyroid.

Graves’ Disease is the most common cause of overactive thyroid (hyperthyroidism) and also typically arises in women under 40 years of age. This AITD presents symptoms similar to Hashimoto’s with some exceptions: a fine tremor of the hands or fingers, heat sensitivity, weight loss, bulging eyes, thyroid enlargement, reduced libido, erectile dysfunction (in men), and menstrual cycles changes (in women). Graves’ disease may also produce a thick, red patch of skin on the anterior portion of the leg or dorsum (top) of the foot referred to as Graves’ dermopathy.

Whether general AITD or a more specific form (Hashimoto Thyroiditis or Graves’ Disease), AITD is most effectively diagnosed with a thyroid antibody test. Given the high prevalence of undiagnosed thyroid diseases, researchers now deem normal TSH ranges as unreliable because undiagnosed individuals were most likely studied to determine those ranges. Thyroid antibody tests can disclose the presence of anti-thyroid antibodies as much as ten years before TSH levels test as abnormal. While medical professionals do not characteristically perform thyroid antibody tests, patients can request them thereby giving themselves the best chance to prevent Graves’ disease and Hashimoto’s Thyroiditis.

Can chemicals cause hypothyroidism9 Steps that Protect the Thyroid from Environmental Damage

Given the widespread presence of thyroid-damaging toxins in the environment, prevention should center on strengthening the thyroid along with avoiding environmental toxins as much as possible. The following are some recommended ways for doing this:

  1. Convert to all-natural toiletries and beauty products free of heavy metals
  2. Avoid using hand soaps and other cleaning agents with anti-bacterial properties
  3. Limit use of plastic containers for drinking and food storage or at least opt for BPA-free varieties (realize that  they may still contain other bisphenol derivatives)
  4. Invest in a quality, reverse-osmosis water filter for water used for consumption and bathing
  5. Consume foods rich in iodine and selenium like seaweed, pastured dairy products, brazil nuts (organic) and fish (avoid farmed fish and opt for white or oily fish that have a short lifespan to avoid build-up of heavy metals like mercury), or take a supplement
  6. For other foods, eat organic varieties as often as possible to avoid toxic agricultural agents
  7. Replace non-stick cookware items with stainless steel or enameled cast iron options
  8. Stop using pesticides, herbicides, and fungicides (or fertilizers that contain them) in the yard and garden
  9. Make all living and working environments as serene as possible to reduce stress and support hormonal balance within the endocrine system

No matter an individual’s gender or genetics, maintaining a healthy, toxin-free environment both externally and internally is the best way to support thyroid health and avoid autoimmune thyroid disease. Pay close attention to changes in energy, weight, and sleep and schedule a thyroid antibody test with an Integrative Health Practitioner today.


Acconcia, F., Pallottini, V., & Marino, M. (2015). Molecular mechanisms of action of BPA. Dose Response, 13(4).

Bajaj, J. K., Salwan, P., & Salwan, S. (2016). Various possible toxicants involved in thyroid dysfunction: A review. J Clin Diagn Res, 10(1): FE01-FE03.

Brent, G. A. (2010). Environmental exposures and autoimmune thyroid disease. Thyroid, 20(7): 755-761.

Cole, W. (2014, January). 11 everyday toxins that are harming your thyroid. Retrieved from MBG at

Ferrari, S. M., Fallahi, P., Antonelli, A., & Benvenga, S. (2017). Environmental issues in thyroid diseases. Front. Endocrinol., 10(3389).

Group, E. (2015, March). 6 toxins that destroy your thyroid. Retrieved from Global Healing Center at

Konieczna, A., Rutkowska, A., & Rachoń, D. (2015). Health risk exposure to Bisphenol A (BPA). Rocz Panstw Zakl Hig, 66(1): 5-11.

Kresser, C. (2017, September). How environmental toxins harm the thyroid. Retrieved from Kresser Institute at

Mayo Clinic. (2018, March). Graves’ disease. Retrieved from

Vojdani, A. (2014). A potential link between environmental triggers and autoimmunity. Autoimmune Dis, 2014(437231).

Wentz, I. (2017, October). Top 6 ways to heal thyroid disease. Retrieved from Greed Med Info at


Recommended For You

About the Author: Tung Chi