Hair dye and cancer

Research findings about the relationship between permanent and semi-permanent hair dye and cancer have been reported by media in the past few years. The studies have looked at hair dye usage and its association with bladder and breast cancer, myeloma, and Hodgkin’s and non-Hodgkin’s lymphoma. The results of these studies have been inconclusive, some have demonstrated an association while others have not. The inconsistency of these results may be attributed to:

Change in hair dye ingredients: There was a change in the ingredients used in hair dye in 1980. Hair dye products prior to 1980 contained chemicals that are known to cause cancer in rodents. Many studies included people who used hair dye earlier than 1980 and, as a result, the findings of these studies may not reflect current risk associated with hair dye use today.
Type of hair dye: Some research shows that dark coloured dyes with a base of coal tar may be more carcinogenic (cancer causing) than lighter colours.
Genetics: Some research shows that individuals who have a slow enzyme for breaking down arylamines (a compound found in hair dye that is absorbed through the skin) are more prone to developing bladder cancer than individuals with a fast enzyme. It has been suggested that the presence of arylamines in the bladder may increase the risk of developing bladder cancer. Genetic testing for this enzyme is currently in the research phase.

Overall, recent studies do not indicate an excess risk of cancer from using hair dye. More research is needed to better understand the role of dye colour and genetics. In the meantime, if you are concerned about using hair dye, the following tips will help reduce your exposure:

use hair dyes less frequently;
use a lighter shade of hair dye;
use gloves during application.

The Canadian Cancer Society will monitor research about this possible relationship and update our health information if appropriate. We are committed to conveying information about cancer risk to Canadians.

Last modified on: 10 December 2009