Hair dye not only changes hair color, it is absorbed directly through the scalp into the bloodstream where it is distributed throughout all cells in the body.
The following hair dye statistics, though not the result of a controlled scientific study, are based on years of following real people:
- Women who use permanent hair dyes once a month for a year or more have twice the risk of bladder cancer compared to those who don’t use dye.
- Women who use permanent hair dyes monthly for 15 or more years have three times the risk of bladder cancer compared to those who don’t use dye.
- Hairdressers who are colorists for at least 10 years have more than 5 times the risk of bladder cancer as those who don’t color hair.
- Hair dyes are implicated in certain blood cancers such as non-Hodgkin’s Lymphoma.
- No increased risk was seen in women who used only semi-permanent dyes or temporary rinses.