1. Can antiperspirants or deodorants cause breast cancer?
Articles in the press and on the Internet have warned that underarm antiperspirants (a preparation that reduces underarm sweat) or deodorants (a preparation that destroys or masks unpleasant odors) cause breast cancer.1 The reports have suggested that these products contain harmful substances, which can be absorbed through the skin or enter the body through nicks caused by shaving.
Some scientists have also proposed that certain ingredients in underarm antiperspirants or deodorants may be related to breast cancer because they are applied frequently to an area next to the breast.2,3 However, researchers at the National Cancer Institute (NCI), a part of the National Institutes of Health, are not aware of any conclusive evidence linking the use of underarm antiperspirants or deodorants and the subsequent development of breast cancer.
The U.S. Food and Drug Administration (FDA), which regulates food, cosmetics, medicines, and medical devices, also does not have any evidence or research data that ingredients in underarm antiperspirants or deodorants cause cancer.
2. What do scientists know about the ingredients in antiperspirants and deodorants?
Aluminum-based compounds are used as the active ingredient in antiperspirants. These compounds form a temporary plug within the sweat duct that stops the flow of sweat to the skin’s surface. Some research suggests that aluminum-based compounds, which are applied frequently and left on the skin near the breast, may be absorbed by the skin and cause estrogen-like (hormonal) effects.3
Because estrogen has the ability to promote the growth of breast cancer cells, some scientists have suggested that the aluminum-based compounds in antiperspirants may contribute to the development of breast cancer.3 Some research has focused on parabens, which are preservatives used in some deodorants and antiperspirants that have been shown to mimic the activity of estrogen in the body’s cells.4
Although parabens are used in many cosmetic, food, and pharmaceutical products, according to the FDA, most major brands of deodorants and antiperspirants in the United States do not currently contain parabens. Consumers can look at the ingredient label to determine if a deodorant or antiperspirant contains parabens. Parabens are usually easy to identify by name, such as methylparaben, propylparaben, butylparaben, or benzylparaben.
The National Library of Medicine’s Household Products Database also has information about the ingredients used in most major brands of deodorants and antiperspirants. The belief that parabens build up in breast tissue was supported by a 2004 study, which found parabens in 18 of 20 samples of tissue from human breast tumors.5 However, this study did not prove that parabens cause breast tumors.4
The authors of this study did not analyze healthy breast tissue or tissues from other areas of the body and did not demonstrate that parabens are found only in cancerous breast tissue.5 Furthermore, this research did not identify the source of the parabens and cannot establish that the buildup of parabens is due to the use of deodorants or antiperspirants.
More research is needed to specifically examine whether the use of deodorants or antiperspirants can cause the buildup of parabens and aluminum-based compounds in breast tissue. Additional research is also necessary to determine whether these chemicals can either alter the DNA in some cells or cause other breast cell changes that may lead to the development of breast cancer.