Aluminum in its usual form is not harmful to the skin or any other body part. It naturally occurs as part of the earth's crust and is commonly used for many products from soda cans to space shuttles. But the ionic and compound forms of aluminum, such as those dissolved in water and those often found in cosmetics, can be toxic in high doses.
Aluminum Compounds in Antiperspirants
Aluminum chloride may cause skin irritation, including contact dermatitis--rash--in some people. Aluminum chloride, aluminum chlorohydrate and, recently, aluminum zirconium tetrachlorohydrex glycine are the most common active ingredients in antiperspirants. Other aluminum compounds are less frequently used. These compounds are generally safe as an underarm antiperspirant but should not be used topically over the entire body because of the health risks associated with overexposure to aluminum ions and compounds, which block sweat glands.
Possible Effects of Aluminum Compounds on Skin
Because aluminum compounds in antiperspirants create a chemical reaction with your sweat and clumping to clog your sweat glands, it may cause irritation in sensitive underarm areas. This may result in allergic reactions like contact dermatitis, acne or itching. If this happens, stop using the product and contact a dermatologist to recommend an antiperspirant with a different compound or concentration of aluminum compound. Many combinations are FDA approved and on the market.
Long-Term Health Risks
Although elemental aluminum poses no health risks, its compounds and ions may cause problems in high concentrations. Usually, to take in enough aluminum ions to cause problems, you must eat, drink or inhale it, but it is also possible to absorb ions through the skin. Health complications occur most often in patients with kidney problems, because they can't effectively rid themselves of the excess. Aluminum toxicity may lead to nerve damage, kidney damage and osteomalacia--vitamin D and calcium deficit--and has been linked to increased instances of Alzheimer's and breast cancer.