A recent study has uncovered a link between hair dyes and relaxers and an increased risk of breast cancer in women. The findings also suggest that the products may influence breast cancer risk differently in black and white women.

Researchers studied more than 4,000 women and found, specifically, dark hair dyes raise the risk of breast cancer in black women, while chemical relaxers and straighteners boost the odds in white women. [1]

The study, published in Carcinogenesis, shows that there is a link between the products and breast cancer, but it does not prove a cause-and-effect relationship. [2]

Lead study author Adana Llanos said:

“Our findings do not suggest that simply using hair dyes, relaxers or both will cause a woman to get breast cancer.”

The assistant professor of epidemiology with the Rutgers School of Public Health and Rutgers Cancer Institute of New Jersey added:

“The reality is that we regularly encounter a variety of harmful exposures, which we have no control over.”

However, she added, “we should limit or reduce the possibility of harmful exposures when we are able to do so.”

The women in the Rutgers study ranged in age from 20 to 75, and hailed from New York City and New Jersey. Of the 4,285 white and black women that participated, nearly 2,280 of them were breast cancer survivors. [1]

Llanos and her colleagues found the following:

  • For black women, dark shades of hair dye was linked to an overall higher risk of breast cancer, and an even higher risk of estrogen positive breast cancer.
  • For white women, the use of relaxers, or straighteners, either alone or together with hair dyes, increased the risk of breast cancer.
  • There was also a higher risk of estrogen positive breast cancer among white women who used dark hair dyes, as well as a greater risk of estrogen negative breast cancer with the use of relaxers.

Overall, use of dark hair dyes by black women was tied to a 51% greater risk of breast cancer. Among white women that used hair relaxers, the risk of breast cancer increased a mind-boggling 74%. [2]

Researchers looked at products such as dyes, chemical relaxers, and deep-conditioning creams containing cholesterol or placenta. Cholesterol is marketed as a moisture restorer, and placenta is sold as a hair repairer.

The Study Raises 3 Questions

  1. Why do the chemicals in hair products boost cancer risk?
  2. Why do the risks posed by chemicals in hair products differ by race?
  3. Why are darker hair dyes potentially more dangerous than lighter dyes?

Llanos has some theories. First, she said research has suggested that the chemicals in hair products may damage DNA, or the body may absorb harmful chemicals. [1]

Researchers have found carcinogenic compounds in the blood of hair stylists, suggesting that products like dyes and relaxers do get absorbed through the skin.

There are fewer explanations for the other questions, though.

Llanos said:

“One hypothesis is that the chemical composition of hair products marketed for and used among whites may differ from the products marketed for use by African-Americans.

More research is needed to determine specifically which compounds and chemicals are dangerous and even which specific consumer products and brands contain those chemicals.”

So as not to throw off the results of the study, researchers adjusted for a wide range of health and lifestyle factors, including history of personal and family health, exposure before birth, use of hormones, reproductive history, physical activity, alcohol use, smoking history, and vitamin consumption. Llanos said it’s possible there are other lifestyle factors that influenced the results.

Said Llanos:

“Our findings do not suggest that simply using hair dyes, relaxers or both will cause a woman to get breast cancer. The reality is that we regularly encounter a variety of harmful exposures, which we have no control over.”

Scientists have been looking into potential links between hair dyes and other hair products and bladder cancer, leukemia, and breast cancer for many years, but the findings have been about as clear as pea soup. The American Cancer Society says most studies examining the association between hair dye and breast cancer haven’t produced any solid evidence. Very few African American women were included in any of the studies.


[1] Medical News Today

[2] Health Day

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