While it’s reasonable to take steps to avoid certain endocrine-disrupting chemicals — and I do — the data are limited, so I don’t worry too much about them. The evidence linking endocrine-disrupting chemicals to cancer is not strong in most cases — and not remotely on par with other known risk factors, such as alcohol and smoking.

What are endocrine-disrupting chemicals?

The endocrine system consists of glands that secrete hormones, like estrogen, testosterone and cortisol, that then interact with targets (receptors) in the body to regulate our growth, development, reproduction, metabolism, energy balance and body weight.

Chemicals that interfere with this complex communication system are called endocrine disruptors. These chemicals work in a variety of ways, including overstimulating receptors, blocking receptors so that normal hormones can’t interact with them and altering hormone production or availability.

What to know about 3 common chemicals

Bisphenol A (BPA)

Bisphenol A (BPA) is a chemical used in the production of polycarbonate plastics and epoxy resins. It belongs to the larger class of chemicals called bisphenols. The primary exposure for most people is through their diet: BPAs can leach into food or drinks from the protective, internal epoxy resin coatings of canned foods and from consumer products such as polycarbonate tableware, food storage containers and water bottles, though the U.S. Food and Drug Administration has said it could no longer be used in sippy cups and baby bottles.

One study conducted by the Centers for Disease Control and Prevention in 2008 found BPA in 93 percent of over 2,500 urine samples collected from people 6 years of age and older. And while some products claim to be “BPA-free,” they may substitute the chemical with other, similar bisphenols.

Laboratory experiments in test tubes and mice have found that BPAs may cause cancer cell growth. While one study found an association between increased blood levels of BPA and prostate cancer, it found no association with BPA levels and breast cancer. Other studies have not found a consistent link between BPAs and cancer.

Despite the compelling laboratory data, there is insufficient research to definitively link BPAs with cancer in humans. That being said, I’ve switched to using glass containers to store food and metal or glass water bottles to minimize my potential exposure.

PFAS

Per- and polyfluoroalkyl substances (PFAS) are chemicals used as oil and water repellents and coatings for cookware, food packaging, carpets and textiles. They’re also known as “forever chemicals,” because once PFAS are created, they persist in the environment because they do not break down like some other chemicals. PFAS can be found in everything from some types of dental floss to certain menstrual products. They can also contaminate drinking water near facilities where they’re manufactured.

The data linking PFAS to specific cancers, while still not at the level of smoking or alcohol intake, is stronger than for BPAs. Higher PFAS blood levels have been associated with kidney cancer, particularly in Black populations. Higher levels were also seen in women with postmenopausal breast cancer, and in men with testicular cancer.

In 2024, the Food and Drug Administration announced that companies were phasing out the use of PFAS in food packaging. And last year, the Environmental Protection Agency set limits for the amount of PFAS in drinking water.

But because PFAS are so ubiquitous, they can be hard to avoid. It’s a good idea for your overall health to consume fresh food that is not heavily packaged or ultraprocessed. This will reduce your PFAS exposure. Several brands of cookware are also now PFAS-free.

Phthalates

Phthalates are chemicals used in cosmetics and personal care products that make plastics more durable. These liquids, which are colorless, odorless and oily, resist evaporation and function as solvents and stabilizers in products such as perfumes, shampoos, hair sprays, nail polishes and cleansers. The most common one in cosmetics is diethyl phthalate (DEP).

Products like chemical hair straighteners and dyes, which have been associated with certain hormone-sensitive cancers, including cancers of the breast and ovaries, may contain phthalates.

One study of sisters in 2020 that included more than 46,000 women found that permanent hair dye use was associated with an increased risk of breast cancer, particularly among Black women, while frequent use of straighteners was linked to a higher risk of breast and ovarian cancer. A more recent study in the same cohort found that any use of straightening products within the previous year was linked to an increased the risk of uterine cancer.

Keep in mind that the overall excess cancer risk is still really low. According to the American Cancer Society, approximately one in eight women, or 13 percent, will develop breast cancer over their lifetime. Permanent dye use may increase that risk by 9 percent, from 13 percent to 14 percent.

Further research is needed to determine whether phthalates are the concern in these products, or if another chemical or factor may be a culprit. In the meantime, I recommend checking to see if your beauty products such as shampoo or chemical hair products contain phthalates, or looking for phthalate-free products. Another option is to choose fragrance-free products and avoid perfumes.

Endocrine-disrupting chemicals are everywhere, and we may learn more in coming years to implicate them more directly as a cancer risk factor. In the meantime, here’s my advice: Focus on taking steps for reducing cancer risk that are backed by stronger evidence. Don’t smoke, reduce your alcohol intake, exercise regularly and eat whole foods.

Mikkael A. Sekeres, MD, MS is the chief of the division of hematology and professor of medicine at the Sylvester Comprehensive Cancer Center, University of Miami. He is author of the books “When Blood Breaks Down: Life Lessons from Leukemia” and “Drugs and the FDA: Safety, Efficacy, and the Public’s Trust.”