Deodorant

A deodorant is a substance applied to the body to prevent body odor caused by the bacterial breakdown of perspiration in armpits, feet, and other areas of the body. A subgroup of deodorants, antiperspirants, affect odor as well as prevent sweating by affecting sweat glands.

Antiperspirants are typically applied to the underarms, while deodorants may also be used on feet and other areas in the form of body sprays. In the United States, the Food and Drug Administration classifies and regulates most deodorants as cosmetics, but classifies antiperspirants as over-the-counter drugs.

The first commercial deodorant, Mum, was introduced and patented in the late nineteenth century by an inventor in Philadelphia, Pennsylvania, Edna Murray. The product was briefly withdrawn from the market in the U.S., but is currently available at U.S. retailers under the brand Ban. The modern formulation of the antiperspirant was patented by Jules Montenier on January 28, 1941. This formulation was first found in "Stopette" deodorant spray, which Time Magazine called "the best-selling deodorant of the early 1950s". Stopette was later eclipsed by many other brands as the 1941 patent expired.

There is a popular myth that deodorant use is linked to breast cancer, but research has shown no such link exists.

Human perspiration is largely odorless until it is fermented by bacteria that thrive in hot, humid environments. The human underarm is among the most consistently warm areas on the surface of the human body, and sweat glands provide moisture, which when excreted, has a vital cooling effect. When adult armpits are washed with alkaline pH soap, the skin loses its acid mantle (pH 4.5 - 6), raising the skin pH and disrupting the skin barrier.As many bacteria thrive in this elevated pH environment, this makes the skin susceptible to bacterial colonization. The bacteria feed on the sweat from the apocrine glands and on dead skin and hair cells, releasing trans-3-Methyl-2-hexenoic acid in their waste, which is the primary cause of body odor. Underarm hair wicks the moisture away from the skin and aids in keeping the skin dry enough to prevent or diminish bacterial colonization. The hair is less susceptible to bacterial growth and therefore is ideal for preventing the bacterial odor.

After using a deodorant containing zirconium, the skin may develop an allergic, axillary granuloma response. Antiperspirants with propylene glycol, when applied to the axillae, can cause irritation and may promote sensitization to other ingredients in the antiperspirant. Deodorant crystals containing synthetically made potassium alum were found to be a weak irritant to the skin. Alcohol-free deodorant is available for those with sensitive skin.[citation needed] Frequent use of deodorants was associated with blood concentrations of the synthetic musk galaxolide.

Aluminum is present most often in antiperspirants in the form of aluminum chlorohydrate.Aluminum chlorohydrate is not the same as the compound aluminum chloride, which has been established as a neurotoxin. At high doses, aluminum itself adversely affects the blood–brain barrier, is capable of causing DNA damage, and has adverse epigenetic effects.

The Food and Drug Administration, in a monograph dedicated to analysing the safety of deodorants, concluded that "despite many investigators looking at this issue, the agency does not find data from topical and inhalation chronic exposure animal and human studies submitted to date sufficient to change the monograph status of aluminum containing antiperspirants", therefore allowing their use and vowing to keep monitoring the scientific literature. Members of the Scientific Committee on Consumer Safety (Europe) concluded that "due to the lack of adequate data on dermal penetration to estimate the internal dose of aluminium following cosmetic uses, risk assessment cannot be performed."

The myth that breast cancer is linked with deodorant use has been widely circulated, and appears to originate from a spam email sent in 1999; however, there is no evidence to support the existence of such a link. One constituent of deodorant products which has given cause for concern are parabens, a chemical additive. According to the American Cancer Society "studies have not shown any direct link between parabens and many health problems, including breast cancer".

The FDA has "acknowledge that small amounts of aluminium can be absorbed from the gastrointestinal tract and through the skin.", leading to a warning "that people with renal dysfunction may not be aware that the daily use of antiperspirant drug products containing aluminium may put them at a higher risk because of exposure to aluminium in the product." The agency warns people with renal dysfunction to consult a doctor before using antiperspirants containing aluminum.

If aerosol deodorant is held close to the skin for long enough, it can cause an aerosol burn—a form of frostbite. In controlled tests, spray deodorants have been shown to cause temperature drops of over 60 °C in a short period of time.

Aluminium zirconium tetrachlorohydrex gly, a common antiperspirant, can react with sweat to create yellow stains on clothing. Underarm liners are an alternative to antiperspirants that do not leave stains.