Deodorant

Our skin contains millions of glands, some of which produce sweat. The sweat passes from the coiled portion of the gland, through a straight sweat duct to the skin’s surface. When we are hot, active, nervous or stressed, our sweat glands are automatically stimulated to produce more sweat to lower our body’s temperature. As the sweat evaporates from our skin, it absorbs heat energy from our body and so cools us down. We have millions of sweat glands all over our body to do this job, and only a small percentage of our body's sweat is produced under the arms. However, perspiration is more noticeable under the arms because it is more difficult for sweat to evaporate from the armpit.

Sweat itself does not smell but bacteria can feed off the sweat and it is these bacteria that make the smell associated with body odour. People control and prevent this body odour in a number of ways. We can prevent body odour by regular washing – particularly of areas where sweat tends to collect. It is important to wash after sport and other strenuous physical activity.

Deodorants can be used under the arm or all over the body (as bodysprays) to control body odour. Deodorants use ingredients such as alcohol and antimicrobials to kill bacteria and fragrance to mask bad smells. Deodorants come in many different forms, including roll-ons, sticks, gels, aerosol and non-aerosol sprays. Which type you decide to use is a matter of personal choice.

Antiperspirants, like deodorants, are also available in a variety of formats and often contain fragrance to make the wearer smell nice. But, unlike deodorants, antiperspirants also contain ingredients to reduce underarm sweating. This means that using an antiperspirant reduces sweat patches under the arm, but without affecting the body's ability to cool itself. Antiperspirants contain ingredients called aluminium salts (or sometimes aluminium/zirconium salts). The main way in which they work is to dissolve in sweat and create a thin coating of gel to cover over the sweat glands. This coating reduces the amount of sweat released onto the surface of the skin for a number of hours after the antiperspirant is applied.

Web links to visit:

	http://www.catie.org.uk/face_value/interactive_home.html
	http://www.bbc.co.uk/science/humanbody/body/ articles/lifecycle/teenagers/hair_and_sweat.shtml
	http://www.bama.co.uk
	http://www.schoolscience.co.uk
	http://www.sciencepages.co.uk