A few studies suggest that chemicals from antiperspirants and deodorants, such as aluminum, are absorbed into the skin in the underarm during shaving.

The authors of some of these studies express concern that the chemicals in deodorant may be absorbed through the skin and cause mutations that lead to breast cancer.

Because most breast tumors start in the part of the breast near the underarm area, some research claims that a link exists between breast cancer and deodorant products.

According to the American Cancer Society (ACS), these assertions are largely untrue, and there are no strong epidemiological studies or scientific evidence to support them.

Keep reading to learn more about what studies suggest regarding possible links between breast cancer and chemicals in deodorants and antiperspirants.

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Aluminum compounds are the active ingredient in many antiperspirants. They work by forming a temporary plug in the sweat duct, preventing sweat from flowing to the surface of the skin.

According to the ACS, some scientists theorize that these aluminum compounds may cause changes in breast cells that can increase cancer risk.

Much of the research on aluminum and breast cancer is outdated. An older 2005 study suggests that because a person’s skin absorbs aluminum, it may play a role in breast cancer development.

The study’s authors claim that the aluminum in deodorant could cause changes to a person’s DNA and genes that could play a role in developing breast cancer.

However, recent research suggests that those claims are not true. A 2021 study of 384 people with breast cancer concluded that there is no significant relationship between the use of aluminum-containing antiperspirants and breast cancer.

Additionally, a large systematic review from 2014 reviewed more than 460 studies addressing the potential health risks of aluminum products. It concluded there was no link between the use of aluminum-containing antiperspirants and an increased risk of breast cancer.

Parabens are preservatives used by manufacturers in food and personal care products, including some deodorants and antiperspirants. When someone applies products with parabens to their skin, a small amount may absorb into the skin and reach the bloodstream.

When parabens penetrate the skin, they can weakly mimic estrogen in the body, which could potentially alter the body’s hormonal balance and “turn on” the growth of hormone receptor-positive breast cancer.

An older 2008 report concluded that despite this effect, the concentrations of parabens in the products it assessed were safe. More recently, a 2021 study found “limited evidence” that parabens and aluminum found in personal care products pose a health risk.

While parabens have been found in samples of breast tumors, the ACS says these results should not be a cause for concern because of the following:

  • While the study showed parabens were present, it did not show they caused the tumor development.
  • Although parabens have weak estrogenic activity, the estrogen produced in the body is hundreds to thousands of times stronger.
  • Parabens are a component of many products, and the study did not find the specific source of the parabens present in the breast tumors. Without knowing the source, there is no way to determine if it came from deodorants.

The Food and Drug Administration (FDA) advises people to avoid wearing deodorants, powders, lotions, or perfume under the arm or on the breast on the day of a mammogram.

According to the ACS, many of these products contain aluminum, which can appear as tiny specks on a mammogram. The specks can resemble small calcium deposits, which are a sign of cancer. Not wearing deodorant prevents inaccurate mammogram results.

Scientists who theorize a possible link between antiperspirants and cancer say cancer-causing chemicals in the products may be absorbed through razor nicks from shaving the underarm.

They claim that the chemicals can enter underarm lymph nodes, which are unable to excrete them through sweating. This causes a high concentration of toxins that can result in cell mutations and lead to cancer.

An older 2002 case-control study indicates that there is no evidence to support the above theory. The authors examined the use of underarm products in 812 individuals with breast cancer and 793 people who did not have breast cancer.

They found no difference in risk between those who shaved with a nonelectric razor and those who shaved with an electric razor.

They also recorded no association between the use of underarm products and a higher risk of breast cancer.

A more recent article from 2019 concluded that the use of antiperspirants does not appear to increase the risk for breast cancer and may even decrease the risk.

The authors noted that regular “maximum use” of deodorant or antiperspirant combined with shaving may be associated with a younger age of breast cancer diagnosis.

However, according to the ACS, this could be because younger women, in general, are more likely than older women to shave their underarms and use antiperspirants.

According to the Centers for Disease Control and Prevention (CDC), getting older (50 years or older) and being a woman are the main risk factors for breast cancer. Below are factors the CDC lists that increase the risk.

Risk factors that a person cannot change include:

  • Age: The risk increases with age. Most cases of breast cancer involve individuals older than 50 years.
  • Reproductive history: People who started their menstrual cycle before age 12 or began menopause after age 55 have a higher risk due to their increased exposure to hormones.
  • Genetic mutations: Individuals with certain inherited genetic mutations have a higher risk.
  • Breast density: People with dense breasts have a greater likelihood of developing breast cancer.
  • Personal history: If someone has had breast cancer, they are more likely to develop it a second time. Research also links certain noncancerous breast diseases to a higher risk of developing breast cancer.
  • Family history: A person’s risk is higher if they have a mother, daughter, or sister with ovarian or breast cancer. It is also higher if they have several family members on either the mother’s or father’s side who have developed one of the cancers.
  • People who took the drug diethylstilbestrol (DES): From 1940–1971, doctors prescribed DES to women to prevent miscarriages. Individuals who took the medication or had a parent who took it while pregnant with them have a higher risk.
  • Previous radiation treatment: Someone who had radiation therapy on their breasts or chest before age 50 has an increased likelihood of developing breast cancer.

Risk factors that a person can change include:

  • Being physically inactive: Not exercising enough increases the risk of developing breast cancer.
  • Taking hormones: Taking hormone replacement therapy that contains both estrogen and progesterone after menopause can raise the likelihood if taken longer than 5 years.
  • Having obesity or being overweight after menopause: Older people with these conditions have a higher risk of developing breast cancer.
  • Drinking alcohol: Research shows the risk of developing breast cancer rises with the amount of alcohol a person consumes.

Some scientists have raised concerns that the aluminum and parabens in antiperspirants and deodorants may cause breast cancer. However, recent research has not found evidence that the products are unsafe.

People who wish to reduce their risk of breast cancer may engage in lifestyle practices that can help. These include exercising regularly, limiting alcohol intake, and maintaining a healthy weight.

However, some risk factors, such as age and sex assigned at birth, are not under a person’s control.