The role of antiperspirant in causing breast cancer is not proven

A widely shared Facebook post makes a number of false or unevidenced claims about the link between breast cancer and the use of antiperspirant deodorant. 

Cancer Research UK told Full Fact that there was “no convincing evidence” to support the claim that breast cancer and antiperspirant deodorant use are linked.

Using antiperspirant deodorant is not the main cause of breast cancer

The main claim in the Facebook post is that antiperspirant deodorant is “the main” cause of breast cancer. This isn’t true. 

Since as early as 2002 (and some say the 1990s), theories have circulated which link breast cancer to antiperspirant deodorants that contain aluminium. This has been linked to an increase in the percentage of breast cancers occurring in an area known as the upper outer quadrant of the breast, near the armpit. As a result, scientists and epidemiologists began to consider whether a lifestyle factor may be the cause. 

Some scientists have theorised that this could be because of aluminium (which is often used in antiperspirant deodorant to reduce the flow of sweat by acting as a ‘plug’) either through effects on particular cells, or parts of cells, or because it may act like  oestrogen on certain receptors in the breast. This is relevant because some breast cancers are significantly influenced by the impact of the hormone oestrogen.  There have also been suggestions that other substances in antiperspirant deodorant may be linked to cancer.

There have been a few different studies to try to investigate the topic, but results have varied. A number of review articles have looked at the studies in the area and suggested that there is no evidence for the link, or called for further research. 

A few studies have shown no link at all, and the one or two that have suggested a link have not been large-scale, long-term studies that have been of sufficient quality to be deemed conclusive. One retrospective study, for example, did suggest that underarm shaving in combination with antiperspirant deodorant use may play a role in breast cancer. But due to the study design, the study’s authors said it could not be conclusive. There were also other factors in the study which may have affected results, and the authors said that further studies are required. 

Rachel Orritt, health information manager at Cancer Research UK told Full Fact: “There’s no convincing evidence that using deodorants or antiperspirants affects breast cancer risk. To know if something causes cancer, we need good quality, long-term studies on people, which take other known risk factors into account—which we haven’t seen for deodorants or antiperspirants.”

She added: “The good news is that there are things you can do that make getting cancer less likely. Keeping a healthy weight and cutting down on alcohol are both proven to reduce the risk of breast cancer.”

The causes of breast cancer are not yet fully understood. There are however, a number of other risk factors that may contribute to the likelihood of somebody developing breast cancer.  

Men are not less likely to develop breast cancer because antiperspirant deodorant is applied to the hair rather than directly on to the skin

The Facebook post also claims that the reason there are fewer breast cancers in men is because they tend to have more armpit hair and therefore antiperspirants would be applied to the hair rather than directly onto the skin. There isn’t evidence to support this.

The American Cancer Society states that “Underarm hair and antiperspirant absorption have not been linked to male breast cancer risk”.

 Instead, it suggests that lower rates of breast cancer in males is due to the fact that men have less breast tissue than women, and other hormonal factors.