Scary Study on Hair Dye & Breast Cancer: 3 Must-Know Facts

Before you pick up the phone to cancel (or schedule) your upcoming hair appointment, read this.

by Lara DeSanto Health Writer

A new study on hair products and breast cancer risk has women around the country second-guessing whether to book their regular hair appointments. But how serious is this connection—and how much should you worry?

The research from the National Institutes of Health found that women who use permanent hair dye and chemical hair straighteners have an increased risk of getting breast cancer than women who don’t use these hair products. The study, published in the International Journal of Cancer, looked at data from nearly 50,000 women in the United States and Puerto Rico.

"Researchers have been studying the possible link between hair dye and cancer for a long time, but results have been inconsistent," said study author Alexandra White, Ph.D., head of the National Institute of Environmental Health Services (NIEHS) Environment and Cancer Epidemiology Group. "In our study, we see a higher breast cancer risk associated with hair dye use, and the effect is stronger in African American women, particularly those who are frequent users. "

The data may be alarming to those women who regularly color or straighten their hair with chemicals. Before you panic, here are some key details about the study and its results to consider.

The Study Is a 'Sister Study'

The research was pulled from data from the Sister Study, a national study of women between 35 and 74 who have a sister who had breast cancer. It’s important to note that having a sister with breast cancer already doubles your risk of getting breast cancer as well, according to UCSF Health.

"The Sisters Study is a good prospective cohort study—but women were recruited to the study because they had a sister with breast cancer, so the conclusions wouldn't necessarily hold true for women in the wider population, hence the need for further confirmation,” Michael Jones, senior staff scientist in epidemiology at the Institute of Cancer Research, told Newsweek.

Race Plays a Major Role

The study found that women who used permanent hair dye on a regular basis in the year before they entered the study were 9% more likely to develop breast cancer than women in the study who didn’t use hair dye. But the amount of risk also differed by race.

Notably, African American women in the study were at a higher risk than white women: Black women who used permanent dyes every five to eight weeks or more had a 60% increased risk of breast cancer, versus an 8% risk for white women who used hair dye just as frequently.

Women who used chemical hair straighteners every five to eight weeks had a 30% higher breast cancer risk—in both white and black women. However, the researchers noted that chemical straightening in general is more common in black women.

The Type of Dye Matters

The results showed differences in the increased breast cancer risk depending on the type of hair dye used. For example, dark hair dye was linked to a 51% increase in risk in black women and an 8% increase in white women. For light hair dye, the risk increased 46% for black women and 12% for white women.

Semi-permanent and temporary dye didn’t appear to raise the breast cancer risk in these women.

Again, race is a key part of the equation here. Per the study’s authors, past research finds that hair products marketed toward black women may have higher levels of endocrine-disrupting chemicals. More research is definitely needed to better discern where this increased risk is coming from.

So, Do We Need to Change Our Hair Routines?

The big question remains: Should women stop dyeing or chemically straightening their hair? Perhaps, say the researchers.

"We are exposed to many things that could potentially contribute to breast cancer, and it is unlikely that any single factor explains a woman’s risk,” says study co-author Dale Sandler, Ph.D., chief of the National Institute of Environmental health Sciences Epidemiology Branch. “While it is too early to make a firm recommendation, avoiding these chemicals might be one more thing women can do to reduce their risk of breast cancer."

If you use a permanent dye or chemical straightener, you may consider switching up your hair routine. Talk to your stylist about the possibility of other coloring methods that may not require as frequent touch-ups, or consider switching to a semi-permanent dye or a color-depositing conditioner. And no matter what change you make, know that it’s not just one factor that impacts your breast cancer risk—monitoring your other risk factors is key, too.

Main Breast Cancer Risk Factors

The major risk factors for breast cancer, per UCSF Health, include:

  • Family history. Again, having a mother, sister, or daughter who has had breast cancer doubles your own risk as well. If you have two of these close relatives who have had breast cancer, your risk increases five-fold. Certain genetic mutations, like BRCA1 and BRCA2, also increase your risk.

  • Race. As previously mentioned, your race can also be an important factor. While white women are slightly more likely to develop breast cancer than black women overall, black women are more likely to develop more aggressive breast cancers and are more likely to die from breast cancer than white women are.

  • Personal breast disease history. If you have personally had cancer in one breast, you’re three to four times more likely to get new cancer in your other breast. Additionally, a certain type of breast disease called atypical hyperplasia, or proliferative breast disease without atypia, may up your chances of getting breast cancer as well. Additionally, if you have received radiation to your chest area as a child or young woman due to other disease, that slightly increases your risk of breast cancer as well.

  • Your period. If you got your first period before age 13 or if you went through menopause after age 50, your risk of breast cancer is slightly higher.

  • Not having kids. If you haven’t had any biological children, or you had your first one after age 30, your risk of breast cancer is slightly raised. Additionally, breastfeeding your children may be a protective factor against risk cancer.

  • Hormone replacement therapy. Using hormone replacement therapy (HRT) for menopause for 10 years or more may slightly raise your breast cancer risk—but the risk goes back to normal within five years of stopping HRT.

  • Alcohol. Alcohol significantly impacts your breast cancer risk. If you have two to five drinks per day, your breast cancer risk is 1.5 times higher than women who don’t drink.

  • Weight and physical activity. If you’re overweight, particularly after you’ve gone through menopause, your risk of breast cancer may be increased. Additionally, even moderate exercise may reduce your breast cancer risk, according to recent research.

  • Breast Cancer and Hair Dye Study: International Journal of Cancer. (2019). “Hair dye and chemical straightener use and breast cancer risk.”

  • Breast Cancer Risk Factors: Taking Charge: Who Gets Breast Cancer? (2019). UCSF Health.

  • News Release on Hair Dye Study: Permanent hair dye and straighteners may increase breast cancer risk. (2019). National Institutes of Health. nih.gov

  • Newsweek Coverage of Hair Dye Study: McCall, Rosie. Breast Cancer Linked to Permanent Hair Dye and Chemical Hair Straighteners in Study of Almost 50,000 Women. (2019). Newsweek.

  • The Sister Study: What Is the Sister Study? (2019). National Institutes of Health. sisterstudy.niehs.nih.gov

Lara DeSanto
Meet Our Writer
Lara DeSanto

Lara is a former digital editor for HealthCentral, covering Sexual Health, Digestive Health, Head and Neck Cancer, and Gynecologic Cancers. She continues to contribute to HealthCentral while she works towards her masters in marriage and family therapy and art therapy. In a past life, she worked as the patient education editor at the American College of OB-GYNs and as a news writer/editor at WTOP.com.