Concern about aluminum
Natural health groups have been pressing government and regulatory agencies for years to take a hard look at the long-term safety of aluminum in cosmetic products. Aluminum is what gives antiperspirants their wetness-fighting ability, and they're highly effective. Commercial deodorants can contain up to 25 percent aluminum salts by weight.
The problem is this: nobody really knows what aluminum does in the human body. In the case of deodorants, you’re applying aluminum directly to the skin and leaving it there. With women, in particular, that skin might be broken from shaving.
You'll notice most antiperspirants contain a warning to discontinue use if you experience irritation from its use, and quite a few people are sensitive to the aluminum salts, parabens and triclosan common in over-the-counter products. But what really worries some health experts is aluminum's possible connection to breast cancer.
Read more: http://www.mnn.com/lifestyle/natural-beauty-fashion/stories/make-the-switch-to-a-natural-deodorant#ixzz3hdVBHdNl