While the American National Institutes of Health have not found any "conclusive evidence" linking antiperspirant usage to breast cancer, there certainly appears to be a connection. The American National Cancer Institute reports:
Aluminum-based compounds are used as the active ingredient in antiperspirants. These compounds form a temporary plug within the sweat duct that stops the flow of sweat to the skin's surface. Some research suggests that aluminum-based compounds, which are applied frequently and left on the skin near the breast, may be absorbed by the skin and cause estrogen-like (hormonal) effects. Because estrogen has the ability to promote the growth of breast cancer cells, some scientists have suggested that the aluminum-based compounds in antiperspirants may contribute to the development of breast cancer.The aluminum compound found in many antiperspirants and deodorants is aluminum zirconium tetrachlorohydrex, which is a known to cause cancer and has other health concerns as well.
As I've mentioned previously, we absorb everything through our skin. There are all sorts of other chemicals and potentially toxic ingredients in mainstream antiperspirants and deodorants just the same as any other beauty or cosmetic product. Check out EWG's Skin Deep Cosmetics Database to see how your antiperspirant or deodorant rates.
According to the Live Strong website the aluminum in antiperspirants may also be linked to kidney problems. A warning label is required by the FDA to be carried by any antiperspirants containing aluminum. They say it is just a precaution for those with kidney disease, though I find it somewhat suspicious.
Though there are rumors saying otherwise, from what I have researched, a toxin build ups is not a concern. I do wonder however if there is something wrong with prevent our body from doing what it is natural designed to do, which is sweat.
On another note, mainstream antiperspirants and deodorants are not cheap, and it only gets more expensive if you seek out store bought natural alternatives. Making your own can save you $4-6 on each stick.
What do you think of antiperspirant?