What are EDCs? An essential guide

The number of synthetic chemicals in our world has exploded since the 1940s. 

World War II created a huge demand for new materials, and from that point on the chemical industry grew quickly, pumping out plastics, pesticides, and petroleum-based products. At the time, these chemicals weren’t designed with human health in mind and little thought was given to how they might affect us [1]. But we’ve since learned that many can quite easily enter our bodies and interfere with our biology, especially our hormones. Today, we call these substances Endocrine Disrupting Chemicals (or EDCs) and exposure to some have been linked to health effects like breast cancer. Even though almost all EDCs are man-made, we still don’t currently know how many there are. This is because most synthetic chemicals have never been fully tested for safety [2]. 

From the food we eat to the air we breathe, EDCs have embedded themselves into our everyday lives. Yet, amid the concern, there is still good news. We know that there are practical steps you can take to reduce your exposure. In this guide, we’ll walk you through what exactly EDCs are, how they affect your body, and what you can do about them. 

What are Endocrine Disrupting Chemicals (EDCs)? 

Put simply, EDCs are chemicals that interfere with your hormones. Common examples include bisphenols and parabens, which are used in a wide range of everyday products. You may have noticed products labelled ‘BPA-free’ in shops – this is bisphenol A, a well-known EDC that is now being restricted in many countries.  

Scientifically, EDCs disturb some part of the endocrine (or hormone) system, which is a network of molecular messages that supports nearly every process in your body. Hormones help regulate things like growth, metabolism, reproduction, and mood.

One of the key challenges with EDCs is that they don’t necessarily behave like most harmful substances. Normally, the ‘dose makes the poison’ which means that, as your exposure goes down, eventually so does the potential harm. However, we now know that EDCs can be more active at lower doses than at higher doses. Some scientists say that this means there may be no completely safe level of exposure [2]. 

This property makes them especially difficult to study and regulate, as many standard safety tests aren’t designed to detect these types of effects. That’s one reason why the current list of known EDCs is probably just the tip of the iceberg. 

Where are EDCs found in everyday life? 

EDCs are surprisingly common in daily life. They lurk in food, packaging, hygiene products, household items, and even in the air and dust of your own home. For most people, exposure happens every single day – through what they eat, what they breathe, and what they touch. 

When talking about EDCs, it’s important to think in terms of groups rather than individual chemicals. That’s because when one harmful chemical is restricted, manufacturers often replace it with a similar alternative that hasn’t yet been tested. For example, ‘BPA-free’ plastics may still contain other bisphenols like BPS or BPF [3]. This means that there is no single product you can avoid which will eliminate exposure entirely. 

Unfortunately, the current policies used to regulate EDCs mostly look at chemicals one by one. So, while governments and regulators catch up, it’s important to understand the main sources of EDCs in everyday life and reduce overall exposure where possible. To help with this, we’ve broken down the most commonly encountered EDCs into six groups; the table below shows where they can be found and how we are exposed. 

How do EDCs affect our bodies? 

EDCs affect our bodies in lots of different ways. To understand what they can do, it’s important to first understand how hormones work. 

Hormones act as messengers in the body, carrying signals to different cells. For a cell to respond, it needs to have the right receptor – like a lock that only a specific key can open [2]. 

Two hormones you might recognise are oestrogen and testosterone. These play important roles in the development and function of reproductive systems. Oestrogen, for example, is crucial for the health of the uterus and breasts and also supports bone growth [4]. 

A helpful way to think about it is to imagine hormones as emails carrying instructions. EDCs interfere with this system in a few ways. Some act like phishing emails, mimicking natural hormones and tricking the body into responding incorrectly. Others block the real messages from getting through, like an inappropriate spam filter. And some disable the system more broadly, like a cyber-attack damaging our email software so we can’t write new ones [5]. 

What makes this even more complicated is that a single EDC can act in multiple ways at once. Combined with their effects at very low doses, this makes it difficult to fully understand their health impacts. It also supports the idea that there may be no level of exposure that is completely safe [2]. 

How do EDCs increase cancer risk? 

There is a growing body of evidence linking EDC exposure to a range of health problems (like breast cancer). This evidence comes from studies in humans, animals, and lab experiments. 

However, proving a direct cause-and-effect relationship is extremely challenging. Almost everyone is exposed to EDCs, so there’s currently no unexposed group for comparison. On top of that, many health effects – like breast cancer – can take decades to develop which means it will take a long time to run the studies needed [6]. 

One way we can show a relationship is large population studies, known as epidemiological research. These studies can uncover strong links, but they can’t prove direct causation (for example, one EDC directly causing a specific cancer). 

Even so, the evidence is strong enough that regulators are beginning to take action. Following a campaign spearheaded by Breast Cancer UK, BPA was banned in baby bottles throughout the EU in 2011. Some phthalates have banned for use in things like children’s toys from 2020 onwards [7]. We know now that health conditions linked to EDC exposure include developmental disorders, diabetes, obesity, and several types of cancer, including breast cancer [8-10]. 

Which EDCs are most strongly linked to breast cancer? 

In the 1940s, a drug called diethylstilboestrol (DES) started being prescribed to pregnant women to prevent miscarriages. Decades later, it was discovered to be an EDC that increased the risk of vaginal cancer strongly and breast cancer moderately. Children born to mothers who were given DES while pregnant also had an increased risk of infertility. By then, millions of women had already been exposed [11].  

The main concern when it comes to breast cancer risk is EDCs that mimic oestrogen, like DES. High levels of oestrogen are associated with an increased risk of breast cancer in both men and women [12, 13]. Although DES is now banned, we are still exposed to oestrogen-like chemicals through our environment. 

Some EDCs, such as BPA, may be able to increase the risk of breast cancer directly [14]. Others may contribute more indirectly, for example by triggering earlier breast development [15] or increasing breast density [16], both of which are known breast cancer risk factors. 

Are EDCs more dangerous during certain life stages? 

It is difficult to carry out the kind of studies needed to say whether EDCs are more damaging during certain stages of life. What is known is that hormones play a major role at specific stages of development. These stages include while you’re in the womb and during puberty, pregnancy, and menopause. This could mean we are more vulnerable to hormone-altering activity during these periods. 

Although there aren’t many studies available, the few results we do have are concerning. Earlier puberty, which has become more common over the past 50 years, can increase breast cancer risk and may be linked to rising exposure to environmental chemicals [2]. Pregnant women may experience higher exposure to certain chemicals, possibly due to eating and drinking more [17, 18]. During pregnancy, EDCs have also been found to cross the placenta and appear in amniotic fluid [19]. 

Because of this, many scientists argue for a precautionary approach. When exposure happens during these sensitive windows, the effects may be long-lasting [20]. Reducing exposure wherever possible is key. 

How do I avoid EDCs? 

Even though sources of EDCs are present everywhere around us, there are still practical ways to reduce your exposure. The most effective changes depend on where your exposure is highest. 

In the kitchen, simple swaps can make a difference. Choosing organic fruit or vegetables can help avoid pesticide residues – as a tip, buy seasonal produce for reduced prices. Switching from plastic containers to glass, and replacing non-stick cookware with stainless steel or ceramic, can also lower exposure. The type of food you buy matters too. Plastic packaging may contain EDCs that can leach into food, so consider buying less canned or packaged food – like getting fewer ready meals or more loose fruit and vegetables from the supermarket [21]. 

In the bathroom, hygiene products can be a source of exposure. Items like shampoos, skin creams, and perfumes can contain parabens, phthalates, and other EDCs. Checking product labels and gradually switching to safer alternatives can help bring down your EDC exposure. The Breast Cancer UK A to Z Chemicals of Concern List can help you identify these chemicals in products. 

Around the home, EDCs can come from everyday items that slowly release chemicals into the environment. This includes things like plastic toys, furniture, and air fresheners. Making small changes over time, such as choosing wooden or cotton alternatives or reducing the use of scented products, can help lower your overall exposure to EDCs. 

What is being done to protect us against EDCs? 

Governments and regulators across Europe have started to take action on EDCs, but progress has been slow. 

In the EU, the main rulebook for controlling chemicals is called the regulation on the Registration, Evaluation, Authorisation and Restrictions of Chemicals (EU REACH). As of March 2026, 148 chemicals are being assessed for endocrine-disrupting properties, with 37 already identified as harmful to human or environmental health [22]. However, scientists estimate that the true number of EDCs is likely in the thousands [2]. Since Brexit, the UK has developed its own version of REACH. So far, UK regulations have lagged behind the EU, with far fewer chemicals restricted [23]. 

That said, there are some positive signs. In early 2025, the EU banned BPA and other hazardous bisphenols in food packaging, and the UK is currently considering a similar move [24, 25]. The EU is also moving towards stricter controls on PFAS chemicals, with a major decision expected soon. Some countries, like Denmark, have already gone one step further by restricting PFAS use in things like clothing. The UK has published its own plan for PFAS, although it’s far less ambitious – but there are indications that the UK may move closer to EU standards by 2028. 

The problem is that regulating one chemical at a time is a slow process. Many experts argue that a broader, more precautionary approach is needed. If we restricted entire groups of chemicals at a time, it would be much harder for companies to keep ‘subbing in’ other players from the same team. 

At Breast Cancer UK, we are campaigning for a full ban on EDCs in everyday products, because incremental change isn't good enough. Add your voice by signing up here. For more on chemicals and breast cancer risk, read our EDCs fact sheet.