Deodorants are personal care products that are applied topically, most commonly on the underarms, to minimize the odor caused by the bacterial breakdown of perspiration. Deodorants are classified as cosmetics by the U.S. Food and Drug Administration (FDA) and typically contain an odor-masking fragrance. Deodorants are generally formulated into a solid, aerosol or liquid base.
Antiperspirants are products whose primary function is to inhibit perspiration. By inhibiting perspiration, which is a necessary component for the growth of bacteria that cause malodor, antiperspirants also act as deodorants. Antiperspirants are classified as Over-The-Counter (OTC) drugs by the FDA because they prevent sweat formation (a biological function). The active ingredient, aluminum-based compounds, gives antiperspirants their sweat-blocking ability by forming a temporary plug within the sweat duct that stops the flow of sweat to the skin's surface. A few commonly used antiperspirant active ingredients are aluminum chloride, aluminum chlorohydrate complexes, and aluminum zirconium complexes.
When an antiperspirant is applied to the skin surface, its antiperspirant active ingredients – usually aluminium salts – dissolve in the sweat or moisture on the skin surface of the armpit. The dissolved substance forms a gel, which creates a small temporary ‘plug’ near the top of the sweat gland, significantly reducing the amount of sweat that is secreted to the skin surface. Bathing and washing will remove the antiperspirant gel. Re-application of antiperspirants can be beneficial to help reduce sweating and keep fresh throughout the day. While antiperspirants reduce underarm sweating, they do not impact the body’s natural ability to control its temperature (thermoregulation). While there are between 2 and 5 million sweat glands in our bodies, relatively few are located in the armpits, which produce only about one per cent of the body's sweat.
Sweating is an essential and natural biological process that starts soon after we are born. Sweating, or perspiring, is the body’s mechanism of keeping us cool. Whether the extra heat comes from hardworking muscles during exercise, from over-stimulated nerves due to stress, or from high air temperatures and humidity, sweating is the body's natural way of regulating its temperature. During extended, vigorous activity, a person can lose several quarts of fluid through the evaporation of perspiration.
There are two types of sweat glands. The eccrine sweat glands, which we are born with and are the most abundant and produce most of the sweat in the underarms, open directly onto the surface of the skin. Apocrine sweat glands, which are triggered by emotions, develop in areas abundant in hair follicles, such as the scalp, underarms, and genitals. Apocrine sweat glands only begin to secrete sweat after puberty, and have little, if anything, to do with temperature regulation.
Sweat itself is odorless. It's the bacteria that live on the skin and break down the sweat that cause the unpleasant odor. Most people have several million sweat glands distributed over their bodies, providing plenty of opportunity for odors to develop. Keeping underarms dry and smelling pleasant are what antiperspirant and deodorant products are designed to do. These products, designed for both men and women, include aerosols, sprays, pumps, roll-ons, solid sticks, gels, and creams.
Like all cosmetic products, deodorant and antiperspirant products and their ingredients must be safe before they are introduced for consumer use. In addition, antiperspirants are regulated by the Food and Drug Administration as Over-The-Counter (OTC) drugs. As such, they must be shown to be safe and effective and must comply with all other requirements listed in the FDA's OTC antiperspirant monograph. Individual antiperspirant active ingredients are reviewed for safety by FDA and only those that are on FDA's antiperspirant monograph approved list may be used in antiperspirant products marketed in the U.S.
Can antiperspirants or deodorants cause cancer?
The rise of the Internet has made it easy for false health claims, scary stories, and rumors to reach millions of people in a matter of minutes. One such myth says that antiperspirants and deodorants may cause breast cancer.
According to the National Cancer Institute (NCI), the breast cancer-antiperspirant myth first appeared in the form of an e-mail in the 1990s, and continues to resurface and recirculate about every year or so. The false information suggests that antiperspirants and deodorants contain harmful substances, which can be absorbed through the skin or can enter the body near the breasts through nicks in the skin caused by shaving.
The NCI says that no existing scientific or medical evidence links the use of underarm antiperspirants or deodorants to the subsequent development of breast cancer. NCI also states that “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.” The Mayo Clinic, the American Cancer Society (ACS), and WebMD experts agree. Razor nicks may increase the risk of skin infection, but not cancer. Some speculate that the myth could have been started by women being told not to wear antiperspirants or deodorants before a mammogram. They were told this, not for safety reasons, but because residue from these products interferes with the X-ray image.
A study of 813 women with breast cancer and 703 women with no history of breast cancer, published in 2002 in the Journal of the National Cancer Institute, found that antiperspirants do not cause breast cancer. A related theory, which suggested that shaving the underarm area increased the risk of deodorant- or antiperspirant-induced breast cancer, was also disproved in the same study conducted at the Fred Hutchinson Cancer Research Center in Seattle, Washington.
The ACS states on its website that “There are no strong epidemiologic studies in the medical literature that link breast cancer risk and antiperspirant use, and very little scientific evidence to support this claim.”
Should I be concerned about parabens in antiperspirant or deodorant products?
Some have speculated that there is a connection between parabens and cancer, and have expressed concern about the use of parabens as ingredients in antiperspirant-deodorant products. They further speculate that parabens can cause cancer by acting like estrogen, a common hormone, through a process called endocrine disruption.
The FDA’s website indicates that based on the published studies and scientific literature of parabens; there is no reliable information showing that parabens, as they are currently used in cosmetics, have an effect on human health. FDA clearly states that most major brands of deodorants and antiperspirants do not contain parabens. Even if these products did contain parabens, scientific studies have shown the estrogen-like activity of parabens to be very weak, and that the estrogen-like activity is observed only with extremely high doses that are far greater than anyone would be exposed to under actual conditions of use or with repeated use. Additionally, many foods also have a weak estrogenic effect in cellular studies. These naturally occurring materials are called phytoestrogens and are present in soy and other fruits and vegetables. Some of these phytoestrogens showed similar results when tested in the same way as parabens. In those studies, parabens were shown to be 10,000 times weaker than the most potent phytoestrogens and 100,000 times less potent than estradiol, the estrogen produced naturally by the body.
Furthermore, in 2008, a group of clinical experts in oncology (i.e., cancer diagnosis and treatment) was created for the purposes of analyzing and reviewing the scientific literature relating to allegation of a link between parabens in antiperspirant and deodorant products and cancer. Fifty-nine studies resulting from a literature search were reviewed and nineteen articles with various methodologies were selected for in-depth analysis. In view of the fact that parabens are generally not present in antiperspirants, the expert group's search related purely to the question of aluminum salts. The expert group's conclusion coincides with those of the French, European and American health authorities. After analysis of the available literature on the subject, no scientific evidence to support the hypothesis was identified, and no validated hypothesis appears likely to open the way to interesting avenues for further research.
The European Union’s (EU) Scientific Committee on Consumer Products (SCCP) also reviewed the evidence regarding a potential link between the use of deodorants/antiperspirants, parabens, and breast cancer in 2005. They concluded that in light of the present knowledge and viewing the fact that the estrogenic potential of parabens has been found to be very low, it was the opinion of the SCCP that there was no evidence of demonstrable risk for the development of breast cancer caused by the use of paraben-containing underarm cosmetics.
Learn more about the safety of parabens here.
Should I be concerned about aluminum in antiperspirant products causing Alzheimer’s disease?
During the 1960s and 1970s, aluminum emerged as a possible suspect as a potential cause of Alzheimer’s disease. This suspicion led to concerns about everyday exposure to aluminum through sources such as cooking pots, foil, beverage cans, antacids and antiperspirants. Since then, numerous studies have failed to confirm that aluminum plays a role in causing Alzheimer’s.
The U.S. FDA has concluded that although "the literature shows the issue of aluminum toxicity and Alzheimer's disease remains controversial and is not resolved," the available evidence is "insufficient to link aluminum to Alzheimer's disease." Almost all scientists today focus on other areas of research, and few experts believe that everyday sources of aluminum pose any threat.
Link to Alzheimer’s Association
Learn more about aluminum here.
Do antiperspirants and deodorants prohibit the release of harmful toxins through underarm lymph nodes?
Some Internet rumors have also suggested that antiperspirants keep a person from "sweating out toxins," resulting in the spread of cancer-causing toxins via the lymph nodes. This theory does not adequately reflect the common understanding of the biological and physiological processes of the human body that work to eliminate waste and other toxins. According to the ACS, while lymph nodes do play a role in waste and toxin removal by helping to clear out bacteria, viruses, and other possible threats to the body, the lymph nodes do not release waste or toxins through the process of sweating. In fact, lymph nodes are not connected to sweat glands. Sweat glands are located in the skin, not in the lymph nodes. Rather, the primary organs responsible for the removal of waste and toxins from the body are the kidneys and the liver. Substances removed by the kidneys are released into urine, while those taken out by the liver are released into bile. The bile then mixes with and is eliminated in the feces.
Mirick, D.K., Davis, S., and Thomas, D.B. (2002) Antiperspirant use and the risk of breast cancer. J. Natl Cancer Inst. 94(20):1578-80.