Deodorant

Deodorants are cosmetic substances applied to the body, most frequently the armpits, to reduce the body odor caused by the bacterial breakdown of perspiration. A subgroup of deodorants are "'antiperspirants'", which prevents odor and reduces sweat produced by parts of the body. Antiperspirants are typically applied to the underarms, while deodorants can also be used on feet and other areas in the form of body sprays.

Human sweat itself is largely odorless. The principal cause of body odor are bacteria thriving in hot, humid environments such as the human underarm, which has a high density of sweat glands and is relatively occluded. The armpits are among the consistently warmest areas on the surface of the human body, and sweat glands provide moisture. Armpit hair adds to the odor because of the increased surface area.

The odor is seen as negative in some cultures (see below), hence many people's desire to eliminate or suppress it. One obvious way to reduce odor is to remove some (or all) of the underarm hair. There are a variety of cultural preferences around this practice.

Deodorants - classified and regulated as over-the-counter (OTC) cosmetics by the U.S. Food and Drug Administration (FDA) - work to inhibit the growth of bacteria which cause odors. The first commercial deodorant, Mum, was introduced in the late nineteenth century. Deodorants are usually alcohol-based, which kills bacteria effectively. Deodorants can be formulated with other, more persistent antimicrobials such as triclosan, or with metal chelant compounds that slow bacterial growth. Deodorants also often contain perfume fragrances intended to mask the odor of perspiration.

The use of Aluminium salts (such as Aluminium chloride) in antiperspirants raises a number of important health issues. While research has yet to conclusively determine specific detrimental effects of Aluminium salts used in antiperspirants, Aluminium is known to have a number of biologically harmful properties. Aluminium is a neurotoxin, it adversely affects the blood-brain barrier, it is capable of causing DNA damage and it has epigenetic effects.[1][2][3] Aluminium salts are thought to have a role in causing breast cancer by interfering with the function of oestrogen receptors.

Most people think that antiperspirants and deodorants are the same thing, but they aren't. Antiperspirants work by clogging, closing, or blocking the pores with powerful astringents such as aluminum salts so that they can't release sweat. (Note that aluminum can accumulate in the brain.) Deodorants work by neutralizing the smell of the sweat and by antiseptic action against bacteria. Deodorants are preferable because they don't interfere with sweating, a natural cooling process.