Question: what do you think about roll on deodrants causing breast cancer?

David Nunan answered on 11 Nov 2015:

This is a very good question and is actually great example of bad science. Rumours that deodorants could cause breast cancer actually started from an email hoax. The original email claimed that deodorants stop your body from sweating out poisons and that toxins buildup under the arm and cause breast cancer. But this is wrong.

Breast cancer actually starts in the breast and only later spreads to the link glands. Your body also has several ways of getting rid of toxins sweating is only one of them. So what is the evidence about chemicals in deodorants and breast cancer? Well it’s actually pretty rubbish in that only a small study found traces of a chemical called parabens in some breast tumours. But funny parabens in tumours is a far cry from saying that it causes breast cancer. To do that you would to compare the levels of parabens in healthy people without cancer and these studies have not been done.

There is also no good evidence that aluminium in deodorants can increase risk of cancer in animals or humans. All the studies that have looked at this have been really small and did not compare levels of aluminium in between women with breast cancer and women without breast-cancer. This is very important as there is no way of knowing if the aluminium is a cause of the cancer without doing this.

All the stories that came out from the hoax email and the small studies caused a scare to a lot of women for no reason.

So you don’t have to worry about going around smelling of BO, you can keep using your deodorant 😉