Antiperspirant Awareness: It's Mostly No Sweat (cont.)

Given the amount of money people spend on personal hygiene products, it would seem that an offensive body odor shouldn't be much of a problem. However, according to Gray's Anatomy, most people have several million sweat glands distributed over their bodies, providing plenty of opportunity for odors to develop.

There are two types of sweat glands. The eccrine glands, which we are born with and which are the most numerous, produce most of the sweat in the underarms. These glands open directly onto the surface of the skin. Apocrine glands, which are triggered by emotions, develop in areas abundant in hair follicles, such as the scalp, underarms, and genitals. These glands only begin to secrete sweat after puberty, and have little, if anything, to do with temperature regulation.

The sweat glands are located in the middle layer of skin called the dermis, which is also made up of nerve endings, hair follicles, and blood vessels. A sweat gland is a long, coiled, hollow tube of cells. Sweat is produced in the coiled part in the dermis, and the long part is a duct that connects the gland to the opening, or pore, on the skin's outer surface. When the sweat gland is stimulated, the cells secrete perspiration that travels from the coiled part of the gland up through the straight tube and out onto the skin's surface.

The American Academy of Dermatology (AAD) says that perspiration is 55 percent to 60 percent fluid, mainly water. Perspiration also contains salt (sodium chloride), as well as trace amounts of other substances, such as ammonia, calcium, chloride, copper, lactic acid, phosphorous, and potassium. These substances, called electrolytes, help to regulate the balance of fluids in the body. The most abundant electrolytes are phosphorous and sodium, which cause sweat to sting the eyes and give sweat its salty taste.

The loss of excessive amounts of salt and water from the body can quickly dehydrate a person and can lead to circulatory problems, kidney failure, and heat stroke. So, although it's literally cool to sweat, it's also important that people drink fluids when exercising or when outside in high temperatures.

Antiperspirants 101

People tend to interchange the words "antiperspirant" and "deodorant," but as regulated by the FDA, they are not the same. Antiperspirants have an aluminum-based compound as their main, "active" ingredient, which can be any number of compounds within an established concentration and dosage form. The active ingredient 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.

The aluminum-based compound is always the first ingredient listed on the back of an antiperspirant container. A few common active ingredients are aluminum chloride, aluminum chlorohydrate, and aluminum zirconium. An "inactive" is any ingredient besides the active ingredient. Some of the inactive ingredients in an antiperspirant include talc, fragrance, and butane, used as an aerosol propellant.

With so many choices available, how do people choose a product that's right for them?

"Looking for a favorite scent is a great way for a consumer to narrow down the search," says Michelle Vaeth, a spokeswoman at Cincinnati-based Procter & Gamble Co. Product development, she says, is constantly driven by what consumers want, and the consumer products company regularly conducts detailed home interviews, quantitative questionnaires, and surveys to get this information.

Another factor is aesthetics, or how a product feels when applied to the skin. "Maybe a woman enjoys the cooling sensation of a clear gel and loves the fact that there's no residue," Vaeth says. Roll-ons tend to have a wet, cool, refreshing feeling upon application, and Vaeth says that many people like how this product feels on their skin after it dries--"they can tell it's still there and working."

Jonathan Hague and Cindy Dumlao, who both work in product development with Unilever, an Anglo-Dutch consumer products company, agree that people tend to go with products they trust. "They want good, high-performance products," says Hague, "and what our consumers think is important to us."

So important, Dumlao adds, that Unilever keeps a database of 18,000 consumers who come to participate in the effectiveness of antiperspirant formulas at the company's clinical and consumer testing facility.

"Basically," she says, "we put people in a hot room, about 100 degrees Fahrenheit, with a relative humidity of 35 percent, and collect their sweat."

The facility is also where "new formulations and fragrances are discovered," says Hague. In his experience, "stick antiperspirants appear to be the preferred dosage form in North America."

Many factors control how effective an antiperspirant is, such as the type and size of the active ingredient used in the formulation.

"Different actives have different levels of effectiveness at stopping sweating," says Timothy J. Long, Ph.D., a scientist with P&G Beauty. The active ingredient also must be pH balanced--basic enough, Long says, not to cause irritation to the skin, but acidic enough to form the solid plugs in the sweat ducts.

The antiperspirant effectiveness test required by the FDA determines that a product is effective or ineffective in its final formulation. But, says Holman, "we do not have any data that suggest any dosage form is better than another." He also says there's a lot of variability between dosage forms. An antiperspirant in finished form may vary in degree of effectiveness because of minor variations in formulation, or in individual interpretation of the directions for its use.