What are endocrine disrupting chemicals?
The endocrine system–and the hormones it uses as signals–is responsible for regulating everything from hunger to growth to fertility[1]. Endocrine disrupting chemicals (EDCs) are substances that interfere with the endocrine system by mimicking, blocking, or interfering with hormonal pathways in the body[2]. EDCs can be either natural or synthetic, and humans can ingest them, inhale them, or absorb them through the skin[3].
In addition to naturally occurring EDCs, the Endocrine Society estimates that upwards of 1000 manmade chemicals can impact the endocrine system[4].
Types of EDCs
With so many known EDCs, and many more that might qualify as such given further study, a comprehensive catalog would be unwieldy. Many of the most common and well-studied EDCs, however, fit into well-studied groups:
- Pesticides and herbicides[5] - Pesticides are often designed to be toxic to insects’ nervous and reproductive systems, and similarities between insect and animal endocrine systems means they can have the same effect in humans. EDCs in this category include DDT (banned in the US in the 1970s, but still in use in other parts of the world), atrazine, glyphosate, and chlorpyrifos (banned in residential areas in the US in 2000, but in use elsewhere). Chlorpyrifos was derived from a chemical warfare agent created by the Nazis.[6]
- Phthalates[7] - This group of plasticizing agents are used to make plastics more flexible and durable, and are also widely used in personal products ranging from nail polish to lotions (including lotions marketed for infants) to body wash. A 2024 study by Consumer Reports found phthalates in 99% of supermarket and fast food products they tested.
- Polychlorinated biphenyls (PCBs)[8] - PCBs are a wide-ranging group of chemicals that were once used in hundreds of industrial applications, including electrical equipment, pigments and dyes, to rubber, plastics, and paints. Banned in 1979, this group of chemicals does not break down easily, and PCBs are still being released into the environment via processes such as municipal waste incineration and improper waste disposal. They may also still be present in older equipment or homes. Once in the environment, they can cycle through the air, water, or food chain.
- Bisphenol A (BPA)[9] - BPA is a component in plastics. It is commonly used in plastic food and beverage storage containers and in baby bottles, as well as in resins that coat the inside of metal food cans, water supply lines, and bottle tops. A 2024 Consumer Reports study found traces of BPA in 79% of supermarket and fast foods they tested.[10]
- Per- and polyfluoroalkyl substances (PFAS) - Also known as “forever chemicals” because of their long persistence in the environment, PFAS are used in a wide variety of industrial applications, from nonstick coatings on pans to flame retardants. For more specific information on this group of EDCs, read our in-depth article here.
- Dioxins[11] - This group of highly-toxic chemical compounds are a byproduct of industrial and human activity, such as burning waste or fuels such as oil, coal, and wood. Forest fires also produce dioxins. Highly persistent in the environment, it’s estimated that over 90% of human exposure to dioxins comes through food consumption, particularly meat, dairy, fish, and shellfish.
- Parabens - Commonly used as preservatives, these are present in a wide array of cosmetic products–including makeup, lotions, and hair care products–as well as in foods and pharmaceuticals. Easily absorbed the human body, they can usually be identified in an ingredients list by the suffix -paraben (e.g., methylparaben, propylparaben).[12][13]
- Triclosan - This antimicrobial, banned by the FDA in some soap products, can still be found in antibacterial soaps, cosmetics, body washes, and popular toothpastes.[14][15]
- Lead & cadmium - These highly toxic heavy metals occur naturally in the environment, and also have been (or still are) used in a variety of industrial applications, including paints, pigments, fertilizers, batteries, gasoline, and plastics.[16]
- Phytoestrogens - These naturally-occurring compounds are found in many plant-based foods. Soy and other legumes are considered a significant source of the isoflavone type. While many of the risks associated with EDCs are balanced out or outweighed by documented benefits to consuming these groups of foods, certain groups–including pregnant and nursing women, and infants–should limit intake of soy because of this.[17]
Common sources of exposure
EDCs are widespread, and many of them are considered persistent organic pollutants (POPs), i.e., chemicals which do not break down readily and can continue to cycle through the air, water, and food chain for years or decades after use[18]. Exposure can occur via three main pathways:
- Consumption - A wide variety of EDCs are used in food and beverage packaging or even directly in food products. Pesticides and herbicides can linger on food products, and many EDCs make their way into groundwater or soil. Both animal and vegetable food sources contain a variety of EDCs because of this.
- Air - EDCs can easily be inhaled, either as particulate matter or in gaseous form.[19]
- Skin contact - Many EDCs can easily be absorbed through the skin.
These categories may seem broad, but testing consistently shows that nearly everyone has some level of synthetic EDCs in their body.[20]
EDCs and cancer
Multiple studies have linked EDC exposure to increased cancer risk and poorer outcomes in diagnosed cancer patients. Prenatal exposure can have a lifelong impact.
EDC exposure, including in utero exposure, is associated with increased risk of[21]:
- Ovarian cancer
- Breast cancer
- Uterine cancer
- Prostate cancer
- Thyroid cancer
- Testicular cancer
Additional health problems linked to EDCs
Because of the diffuse nature of the endocrine system and the variety of body systems it affects, EDCs can lead to a wide variety of poor health outcomes. Exposure has been linked to:
- Fertility issues - Both male and female fertility problems have been tied to multiple groups of EDCs. This can arise as direct changes to the reproductive tissues and organs, or in lower sperm or egg counts or quality.[22]
- Congenital abnormalities - Multiple studies have shown links between EDC exposure in utero and low birth weights, negative impacts on fetal growth, thyroid dysfunction, lower IQ[23], and neurological disorders.[24]
- Immune system - EDC exposure in utero and infancy has been linked to lower immune responses, and other studies suggest EDCs can lead to immunodeficiency, overactive immune responses, and autoimmune disorders.[25][26]
- Obesity - Studies of DDT[27] show a strong tie between exposure and obesity, which is a risk factor for many forms of cancer. Other studies have shown that exposure to a variety of other EDCs, particularly neonatal and in utero exposure, correlates with increased obesity, as well as an increase in the body’s retention of fat-deposited EDCs (creating the possibility of spiraling health consequences).
- Diabetes - Multiple studies[28] have tied EDC exposure to an increased risk of diabetes, which is itself a significant risk factor for multiple types of cancer.
- ADHD - Studies have linked exposure to EDCs, in particular phthalates, to ADHD in children and adolescents.[29]
- Cardiovascular disease - Studies have shown links between EDC exposure and cardiovascular disease. Long-term exposure negatively impacts overall cardiovascular health.[30]
How to reduce your exposure
EDCs are pervasive; completely eliminating exposure is likely impossible. That said, simple steps can significantly reduce the variety and concentration of EDCs you’re exposed to:
- Filter your water - Microplastics and PFAs are common in drinking water, and pesticides and naturally occurring EDCs can easily make their way into water sources. A high-quality filter, such as those recommended by the Environmental Working Group, can reduce or eliminate many of these compounds from your drinking water.
- Replace your nonstick cookware - The chemicals used to create nonstick coatings may include EDCs, which can make their way into food during cooking if pans are overheated, scratched, or otherwise used improperly. In order to avoid any concern about these products–which may include known EDCs or simply not have been thoroughly studied–you can replace chemically-coated nonstick pans with stainless steel, enamel, or cast iron cookware.
- Check your personal products - Phthalates, parabens, and triclosans are common in many personal care and cosmetic products. Check ingredients lists on personal care products, or seek out phthalate-, paraben-, and triclosan-free versions to avoid these contaminants. Bear in mind that phthalates are often used to add fragrance (or directly in commercial colognes and perfumes); avoiding scented products can also reduce your exposure.
- Eat organic - In the US, organic food must be grown and processed without the use of synthetic fertilizers or pesticides.[31] Eating organically-grown foods and organically-raised proteins can significantly reduce your exposure to these classes of EDC.
- Avoid antibacterial soaps - Many soaps labeled antibacterial contain triclosan (as do some toothpastes). You can check labels–these products are considered over-the-counter drugs by the FDA, and are therefore required to list ingredients[32]–or use this database to see if your favorite products contain this EDC.
- Avoid plastic food containers - While many plastics are now BPA-free, the alternatives being used have not been widely studied. Moreover, many food containers (including those labeled with recycle code 3 or 7)[33] and older plastic products may still contain this dangerous chemical. Using glass or silicone-based food storage containers is the safest alternative. When using plastic containers, avoid heating foods in them, as heat can cause more BPA to leach into your food.
The Verdict
EDCs are a significant risk factor for a variety of health issues and neurological conditions, and should be avoided whenever possible. Lifestyle and dietary changes can significantly reduce your exposure.
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