Many hair dyes and various straightening chemicals contain carcinogens that interfere with the endocrine system. Regular use of these products can increase your risk of developing breast cancer.
This is not the first time researchers have investigated the carcinogenic potential of hair dyes and straighteners. A large study confirmed the association between hair care products and breast cancer risk in women of different ethnicities. The research was conducted on the basis of data collected from more than 45,000 healthy women, between 35 and 74 years of age, involved in the "Study of Sisters", a study carried out with the sisters of women with breast cancer.
Hair straighteners and formaldehyde, a substance that causes cancer
Participants, enrolled between 2003 and 2009, answered questionnaires that included questions about the possible use of hair beauty products in the twelve months prior to the start of the study.
The women were monitored over time and nearly 3,000 became ill with breast cancer. Of these, 55% used permanent colorants or chemical straightening treatments for 5 to 8 weeks in the months before the onset of the disease.
The use of these products, especially if it is frequent, has led to greater risks for black and brown women than for white women. As for dyes, they can increase the chances of getting breast cancer in 45% of African American women and in 7% of white women.
In women, either black or white, who used chemical treatments to straighten their hair, the chance of developing breast cancer was 30% higher compared to women who did not use these treatments.
The study therefore concluded that the application of permanent colorants and straightening products may play a role in breast carcinogenesis.
There was no significant association between the appearance of breast cancer and the application of semi-permanent or temporary shades.
It's best to avoid resorting to chemical straightening treatments, and if you want to cover gray hair or change hair color, choose natural products or temporary dyes.
Article in Portuguese