EDCs and breast cancer.

What is the link?

How do Endocrine Disrupting Chemicals (EDCs) affect my breast cancer risk?

Some EDCs have been found to mimic oestrogen and affect the mammary gland in animals. This suggests that they may be involved in breast cancer.

Human studies have shown that some EDCs, such as DES, which is now banned, are linked to an increased breast cancer risk. However, for most EDCs, the possible link with breast cancer is still under investigation.

Minimise pesticide exposure.

Choose fresh organic products where possible to reduce exposure to pesticides.

Ditch non-stick and plastic.

Choose safer cookware and storage. Store food in glass containers and avoid plastic and non-stick cookware.

Check cosmetics ingredients.

Replace products as they run out with safer alternatives. Avoid products containing fragrances.

Key facts about EDC exposure.

The endocrine system regulates our body and organs using hormones as chemical messengers.
Testosterone is the main male hormone, while oestrogen and progesterone are the main hormones in females.
High levels of oestrogen increase breast cancer risk in both men and women.
EDCs are chemicals present in everyday products that may interfere with our hormones and the messages they carry to our organs.
EDCs may be linked with several health issues, including breast cancer.

Examples of EDCs and where they're found.

How are we exposed to EDCs?

EDCs may enter our body from contaminated food and water or be absorbed through our skin by cosmetics and other products. They have been found in many body fluids and tissues, including blood, urine, amniotic fluid, breast milk and breast tissue.

Are EDCs present in everyday products?

EDCs may be present in many products, including cosmetics and beauty products, cookware, food packaging, toys, furniture, cleaning products and more. EDCs in everyday items may be released into the environment when using products or during their manufacture, with some persisting for long periods. This can then lead to unintentional exposures.

What is the cocktail effect?

In our everyday lives, we may be exposed to mixtures of many different EDCs and not to one chemical at a time. This is due to the large number of EDCs used in everyday products. The overall effect of an EDC mixture may be more harmful than any individual chemical alone. This cumulative harmful effect of mixtures is true even if each chemical within the mixture is at levels considered safe. This is known as the cocktail effect.

Diagram highlighting the male (right) and female (left) endocrine system.

What is the endocrine system?

The endocrine or hormone system consists of all the glands and organs that produce hormones. Around 50 different hormones act as chemical messengers that are released into the blood stream and allow different organs to communicate with each other.

Hormones control our body’s growth, development, metabolism and reproduction.

What are the sex hormones?

Testosterone, produced by the testis, is responsible for developing the male reproductive organs and regulates sperm production.

The ovaries mainly produce oestrogen and progesterone. During puberty, oestrogen is responsible for the development of the female reproductive organs, as well as the breasts.

Oestrogen regulates the menstrual cycle, while progesterone prepares the uterus for pregnancy. Progesterone is also produced by the placenta throughout pregnancy to support it and, alongside oestrogen, prepares the breast for breastfeeding.

When an individual goes through menopause, the amount of female hormones produced by the ovaries is greatly reduced, and the fat tissues become the primary site of oestrogen production.

Do hormones play a role in breast cancer?

High levels of oestrogen increase breast cancer risk in both men and women. In women, prolonged exposure to oestrogen throughout life, caused by early puberty or late menopause, may also increase breast cancer risk.

Testosterone has also been linked to an increased risk of breast cancer in women in some studies, however, more research is needed in this area. Meanwhile the evidence of a possible link between progesterone and breast cancer is inconclusive.

Can EDCs cause other health problems?

EDCs may be linked with health issues, including diabetes, obesity, cardiovascular diseases, fertility, thyroid diseases, neurodevelopmental problems, and some cancers.

The harmful effects of EDCs depend on the dose and time of exposure. During certain life stages, we may be more susceptible to lower doses of EDCs, which may cause health issues later in life.

Ask the scientist: Is there a top 5 list of harmful chemicals to avoid?

Start your prevention journey today.

To begin reducing your exposure to EDCs, choose one of these actions to commit to this week:

Stop microwaving food in plastic: switch to glass or stainless steel containers for storing and reheating all food. Heat can cause EDCs like BPA and phthalates to leach out of plastic and into your meal.
Avoid synthetic scents: skip any product labelled with just "fragrance" or "parfum," as this often hides phthalates and other EDCs. Choose unscented products or those that list specific essential oils.
Clean up your dust: dust all surfaces with a damp cloth and vacuum at least once using a vacuum cleaner with a HEPA filter (if you have one). Also, open your windows for at least 10 minutes a day to ventilate your home.

Remember, these small steps can make a big difference. Which one will you try first?

Further reading

Use our list, A to ZChemicals of Concern, to check if products contain harmful chemicals.

Download our free Guide to EDCs in your home.

Last review: Feb-24 | Next review: Feb-27.

1. Hiller-Sturmhöfel S, Bartke A. The Endocrine System: An Overview. Alcohol Health Res World 1998;22:153–64. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6761896/.
2. Nounu A, Kar SP, Relton CL, Richmond RC. Sex steroid hormones and risk of breast cancer: a two-sample Mendelian randomization study. Breast Cancer Research 2022;24. https://doi.org/10.1186/s13058-022-01553-9.
3. Trabert B, Sherman ME, Kannan N, Stanczyk FZ. Progesterone and breast cancer. Endocr Rev 2019;41. https://doi.org/10.1210/endrev/bnz001.
4. Gore AC, Chappell VA, Fenton SE, Flaws JA, Nadal A, Prins GS, et al. EDC-2: The Endocrine Society’s Second Scientific Statement on Endocrine-Disrupting Chemicals. Endocr Rev 2015;36:1–150. https://doi.org/10.1210/er.2015-1010.
5. Kay JE, Cardona B, Rudel RA, Vandenberg LN, Soto AM, Christiansen S, et al. Chemical Effects on Breast Development, Function, and Cancer Risk: Existing Knowledge and New Opportunities. Curr Environ Health Rep 2022;9:535–62. https://doi.org/10.1007/s40572-022-00376-2.
6. Howdeshell KL, Hotchkiss AK, Gray LE. Cumulative effects of antiandrogenic chemical mixtures and their relevance to human health risk assessment. Int J Hyg Environ Health 2017;220:179–88. https://doi.org/10.1016/j.ijheh.2016.11.007.

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