You may have heard the theory that using deodorant may increase your risk of breast cancer.

One reason for this concern may be that breast cancer is most likely to occur in the upper, outer quadrant of the breast. That’s the section closest to the underarm.

To date, there’s no clear evidence linking deodorants to the development of breast cancer.

Read on as we look at some of the research about deodorant and breast cancer as well as ways to avoid certain ingredients if you still want to reduce your exposure.

The American Cancer Society (ACS) and the National Cancer Institute say there are no strong studies or scientific evidence linking breast cancer risk with deodorants and antiperspirants.

Through the years, studies have produced conflicting results. But none have found a cause-and-effect connection that directly shows whether using deodorant with certain ingredients has any direct effect on breast cancer risk.

A 2002 study published in the Journal of the National Cancer Institute compared 813 women with breast cancer to 993 women without breast cancer. The researchers found no links between antiperspirants, deodorants, or underarm shaving and breast cancer.

Research published in 2003 and 2009 suggests that these links are possible. But the study authors could not provide substantive evidence supporting a direct connection.

A small 2004 study of 20 breast tissue samples that was published in the Journal of Applied Toxicology found that some samples of breast tumors contained small amounts of paraben. Parabens are preservatives used in many underarm products, including deodorants.

As the ACS explains, the research didn’t explore the source of the parabens or demonstrate any link between the parabens and breast cancer. Parabens can be found in a variety of personal care products and foods, so deodorant may not have been the primary cause or even the source of the parabens.

The ACS further notes that parabens have some estrogen-like properties. But natural estrogens in the body are many times stronger and more likely to play a role in breast cancer.

A 2005 research article published in the Journal of Inorganic Biochemistry states that aluminum present in many antiperspirants can damage DNA and may interfere with estrogen. The author stresses the need for more studies to examine this possible connection.

A case-control study published in 2017 in The Lancet involved 209 females with breast cancer and 209 healthy people as a control group for comparison.

The research suggests that women who use underarm cosmetic products (UCPs) several times a day starting before age 30 may have an increased risk for breast cancer. Tissue samples also showed that women with breast cancer had more aluminum in their breast tissue than the control group.

But in this study, history of deodorant and antiperspirant use was self-reported. This can create a recall bias, meaning that people may not remember their exact patterns of use.

And most women in the study didn’t know whether the products they used in the past were antiperspirants containing aluminum or deodorants, so researchers grouped the products together under the term “UCPs.”

This study did not indicate that deodorants or antiperspirants could increase the risk of breast cancer. But the researchers did recommend careful use of UCPs.

A 2014 review in the journal Breast Care looked at breast cancer risk and lifestyle factors, including deodorant use. Citing several studies on aluminum and parabens, the researchers found no convincing evidence linking them to breast cancer and simply stated that more studies are needed.

In the same year, a large systematic review published in the Critical Review of Toxicology looked at health risks posed by aluminum. The researchers found no clear evidence that using underarm products or cosmetics that contain aluminum increases the risk of breast cancer.

It’s important to point out the differences between deodorants and antiperspirants. The Food and Drug Administration (FDA) lists deodorants as cosmetics, while it lists antiperspirants as drugs.

Deodorants contain ingredients designed to mask odors. Antiperspirants contain ingredients that block pores and decrease sweat. Some products do both.

There’s no scientific evidence linking deodorants or antiperspirants with breast cancer. But two ingredients are often brought up as cause for concern: aluminum and parabens.

Aluminum is the active ingredient in antiperspirants — it’s what cuts down on underarm sweat. Deodorants don’t contain aluminum. Switching from antiperspirants to deodorants can reduce your exposure to aluminum.

On labels, you might find aluminum listed as:

  • aluminum chlorohydrate
  • aluminum compounds
  • aluminum salts
  • aluminum zirconium tetrachlorohydrex GLY

Parabens are preservatives that help prevent fungi, bacteria, and yeast from growing in cosmetics and personal care products. According to the FDA, most major brands of deodorants don’t contain parabens. You’ll see them listed on the label by names such as:

  • butylparaben
  • ethylparaben
  • methylparaben
  • propylparaben

Using deodorant instead of antiperspirant can help you reduce your exposure to both ingredients.

Everyone’s body is different. What works for someone else won’t necessarily work for you.

There are quite a few natural and do-it-yourself deodorant alternatives you can try.

One such product is baking soda deodorant. It won’t prevent sweating, but it can help absorb odor without aluminum, parabens, or other ingredients you want to avoid.

Crystal deodorant, which is made from natural mineral salts, is another option.

Keep in mind that “natural” doesn’t always mean a product is completely safe. Be sure to check out the list of ingredients.

Stop using anything that irritates your skin. It might also help to speak with a dermatologist about which personal care products are best for you.

If you’re concerned about sweating a lot, there are a few things you can do that might help you sweat less under your arms:

  • Wear loose-fitting clothing.
  • Choose natural, breathable fabrics over synthetic when possible.
  • Wear underarm sweat shields.
  • Use air conditioning and personal fans when you can.
  • Change your shirt if it gets sweaty.

Some sweat is totally normal and even good for you. It’s your body’s way of cooling down. But you can also pat your underarms dry with an absorbent towel as needed, as long as it doesn’t irritate your skin.

Consult a healthcare professional if too much sweating is a problem for you despite your best efforts. There may be an underlying cause, known as excessive sweating (hyperhidrosis), which is treatable.

There’s not enough evidence to support the theory that using deodorants or antiperspirants increases breast cancer risk. More strong epidemiologic studies on this subject are needed.

If you prefer to be cautious anyway, read labels and choose underarm products carefully. Avoid aluminum, parabens, and any other ingredients you’re concerned about.

A variety of deodorants meet these needs. You can also go all-natural and learn how to make your own deodorants.

If you’re still concerned about your breast cancer risk, consider reading up on other modifiable risk factors that can help you reduce your risk in other ways.