Breast Cancer from Anitpersperant?

A friend of mine recently shared a post on facebook that stated antiperspirants cause breast cancer near the armpit because they are full of toxins and cancer causing agents that get absorbed into your skin, and that washing the antiperspirant off before bedtime will prevent such effects.

This is a perfect example of half-truth being presented as a health warning or safety tip.

First, lets discuss why your pits stink:

Arm pits are typically a warm area of your body and when your skin is warm it will release sweat (essentially salt water) in an attempt to cool off. When the water evaporates from the surface of your skin it absorbs heat - the transformation from liquid to vapor is an endothermic process. The heat on the surface leaves your skin with the water. Sometimes you sweat out a bit of sugar (not quite the same kind you put in your morning coffee) or some small proteins - particularly while sweating more actively. These sugars and small proteins are the ideal food source for the bacteria that live in the moist environment under your arms. They break them down and create waste products that smell bad. Hence the stinky arm pits.

Second, lets define Deodorant and Antiperspirant:
They are not the same thing, however these terms are often used interchangeably.
Both are applied to the armpit with the goal of reducing odors caused by sweat and the bacteria that grow in your underarm.

Deodorant accomplishes this by basically putting perfumes and odor absorbing or destroying compounds on the skin to keep you smelling fresh even in the presence of sweat.

Antiperspirant is usually deodorant with added aluminum or aluminum containing molecules. The aluminum acts to clog the ducts that carry sweat from your glands to the surface. This will not usually clog 100% of your sweat ducts but should affect a large number of them. So no matter how warm your pits get, no matter how much sweat is produced in the glands, it cannot escape to the skin and therefore cannot be broken down by the bacteria. No sweat = no stink!

You can usually identify one from the other based on packaging that says things like "Keeps you dry" or better yet, turn the thing over and read the ingredients. Antipersperants will have ingredients like "Aluminium chloride, aluminium chlorohydrate, aluminium zirconium tetrachlorohydrex gly and aluminium zirconium trichlorohydrex gly."
WebMD explored the other components of deodorants and antiperspirants.

Now, lets break down the claims in the post.

1 - Antipersperant is full of toxic chemicals that cause cancer - are you kidding me? There are so many regulations around everything you buy that no company would even consider adding a known toxic compound to a product intended to be applied to the skin. Additionally, antipersperant is classified as a drug (while deoderant is a cosmetic) and therefore is subject to FDA approval. The FDA investigated the safety of aluminum in antiperspirants and found the levels of aluminum containing compounds to be well within safe limit and only cautions people to refrain from eating antiperspirants and inhaling aerosol varieties; however, this was not solely due to the presence of aluminum.

2 - These supposed toxins will be absorbed through your skin. Percutaneous absorption is a difficult task to acheive. If there were toxic chemicals in your antipersperant, the chances of them being absorbed through your skin would be slight. The skin is a highly impervious membrane which only allows certain very small molecules with specific properties through. Ionization and hydrophobicity are some of the important aspects that govern what may and may not pass through the surface of your skin - they must have just the right charge and just the right relationship with water and fats. The only potential scenario for these chemicals to enter your body is if the skin is comprimised in some way due to cracking or cuts. Even then, the amount of toxins to enter these defects are highly unlikely to reach a concentration high enough to cause any real damage.

3 - Once in your body the chemicals will alter your DNA and induce cancer. This one is not so far fetched - if you can get past the absence of the compounds and the impermeable barrier of the skin. If there is a carcinogen in one of your cells, then yes it could potentially result in cancer. See Cancer: Not a bunch of dead cells.

4 - Washing antipersperant off your skin before bedtime will prevent any adverse effects the toxins may cause. Honestly, who comes up with this stuff? If there are so many toxic chemicals in the antipersperant and it has been sitting on/absorbing into your skin all day, then how will removing it from the surface for the night time prevent those supposed ill effects? Logically, it should follow that some of the toxins have already absorbed into your body and rising them off the skin would not have any effect on those toxins.

Finally, the truth behind the lies:
There is a slight ounce of truth behind these claims however they are lost, buried in the fear mongering.
Aluminum clogs sweat ducts, this can cause some inflammation and irritation to these ducts. This is much more likely to lead to cancer than any theoretical toxins that are magically absorbed through the skin.
It has also be shown that aluminum can have estrogen like effects and therefore can theoretically cause breast cancer. This, however, would require a sufficient amount of free aluminum to cross the skin and accumulate in breast tissue - keep in mind most antiperspirants use aluminum containing compounds not just pure aluminum. Nevertheless, research has been done to investigate this theory and no evidence has been found to support the claim.
You may have also seen articles claiming a link between antiperspirants and other health concerns such as Alzheimers Disease and kidney disease. And, again, there is no evidence to support these claims.

Conclusion: NO - Antipersperant does not cause cancer, Alzheimers, or kidney disease. But if you are concerned about the aluminum in them the logical answer would be to use deodorant rather than antiperspirant (as opposed to washing your pits before bed - but your coworkers might like it if you do that anyway).