Many deodorants designed to cover up body odor also contain an antiperspirant to stop sweat. Aluminum makes an effective antiperspirant because it blocks the sweat glands in the underarm area. Natural deodorants usually don't contain any aluminum -- instead, they ward off unpleasant odor with plant-based ingredients and essential oils.
Aluminum in Deodorant
Some reports have associated aluminum with certain cancers, bone disease and impaired motor function. However, according to the National Cancer Institute and the U.S. Food and Drug Administration, there is no evidence that aluminum-based deodorants are cancer-causing or unsafe. The Alzheimer's Association states that aluminum exposure has not been found to cause Alzheimer's disease. Aluminum can ruin clothing, though -- when it reacts with sweat, yellow stains may develop on the underarms of shirts.
How Natural Deodorant Works
Natural deodorants are typically free of aluminum and other chemicals, including parabens and artificial fragrances. People with sensitive skin or allergies may be able to use natural deodorants with little or no irritation. These products don't block underarm glands, but because of this, they also won't prevent the user from sweating. They fight odor-causing bacteria with essential oils, such as rosemary, lemongrass, lavender and citrus oils. Some deodorants contain a form of aluminum called potassium alum. Unlike aluminum, though, alum only fights odor -- it does not prevent sweating.