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 these studies express concern that the absorbed chemicals may cause mutations that lead to breast cancer.

Other research claims that a link exists between breast cancer and these products because most breast tumors start in the part of the breast near the underarm area. Some researchers also contend that men have a lower risk of breast cancer, as they do not shave their underarms.

According to the American Cancer Society (ACS), these assertions are largely untrue. There is very little evidence to support these claims.

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 antiperspirants. They form 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 the compounds may cause changes in breast cells that can increase cancer risk.

An older 2005 study illustrates the concern about aluminum in antiperspirants. It suggests that because the skin absorbs the chemical, it may play a role in breast cancer development. The authors state that aluminum is toxic to the genes, as it can cause DNA and other genetic changes. They urge further research to assess the effects of long-term use of the products.

However, a systematic review from 2014 indicates the concern does not have merit. It reviewed studies that explored the potential health risk of exposure to aluminum compounds in products. The authors cite several investigations that concluded there was no link between the use of aluminum-containing antiperspirants and an increased breast cancer risk.

Parabens are preservatives used by manufacturers in food and personal care products, including some deodorants and antiperspirants. The skin can absorb these preservatives.

An older 2008 report notes that parabens mimic estrogenic activity. This is a concern because estrogen increases the growth of breast cells, including those that are cancerous. Despite this effect, the authors conclude that the concentrations of parabens in the products they assessed were safe.

Older research from 2004 discovered small amounts of parabens 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 incorrect 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 contend that the chemicals 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 non-electric 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.

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.
  • 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 mothers who took it while pregnant with them have a higher risk.
  • Previous radiation treatment: Someone who had radiation treatment on the breasts or chest before age 50 has an increased likelihood.

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 overweight after menopause: Older people with these conditions have a higher risk.
  • Drinking alcohol: Research shows the risk rises with the amount of alcohol a person consumes.
  • Having a reproductive history of certain factors: These include not breastfeeding, having the first pregnancy after age 30, and never having had a full-term pregnancy.

Learn more about breast cancer.

Some scientists have raised concerns that the aluminum and parabens in antiperspirants and deodorants may cause breast cancer. However, reviews of the body of research on the topic do not find 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.