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.

Endocrine Disrupting Chemicals, or 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.

Our tips to reduce your risk

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

Choose fresh organic products where possible.

Dust and vacuum your home often.

Check cosmetics ingredients.

Avoid products containing fragrances.

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, allowing organs to communicate. 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, while the evidence of a possible link between progesterone and breast cancer is inconclusive.

What are EDCs?

Endocrine Disrupting Chemicals, or EDCs, are harmful chemicals that may interfere with the endocrine system by mimicking or blocking the action of hormones.

Most EDCs are manufactured and include:

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 may be released into the environment from products or during manufacturing, with some persisting for long periods.

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.

Can EDCs cause 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.

Are EDCs linked to breast cancer? 

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.

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. The overall harmful effect of an EDC mixture may be given by adding together the effects of the different EDCs. This, known as the cocktail effect, means that mixtures may cause harmful effects even if each chemical is at levels considered safe.

Please see our Endocrine disrupting chemicals science review, for more details and references.

Use our A to Z Chemicals of Concern list to check if products contain harmful chemicals.

Help prevent breast cancer in future generations

Now more than ever, we need your help. Together we can help lower people’s risk of developing breast cancer. If you’ve found the information on our website helpful, then please consider making a donation today. Thank you.