Is there a confirmed link between hair dye and breast cancer?
The short answer is: not definitively for most women — but the picture is more concerning for Black women specifically. Overall, the results of studies that have looked at possible links between hair dyes and breast cancer have been mixed and inconsistent, and none conclusively show whether or not hair dyes can cause breast cancer [1]. Most studies, including a meta-analysis combining the results of 14 studies, have found no increased risk of breast cancer among women who use permanent hair dye, though some findings suggest a slight increase in risk [2]. However, research has consistently found that Black women face a disproportionately higher risk: one major NIH study found a 45% increased risk in Black women compared to a 7% increased risk in white women [3], and among African American women using permanent dyes every five to eight weeks or more, the risk was as high as 60% compared to 8% for white women [4]. This disparity, combined with the fact that Black women already face a 40% higher breast cancer death rate than white women [5], makes this an area of particular concern.
What does the largest study on this topic show?
In the largest study to date, which followed 117,200 women from the USA over 36 years, a research team led by Eva Schernhammer of the Medical University of Vienna showed that regular hair coloring had no significant effect on most types of cancer — with a few exceptions. The study did find a positive association for hormone receptor-negative breast cancer [6].
What did the major NIH study find?
Using data from 46,709 women in the Sister Study, researchers at the National Institute of Environmental Health Sciences found that women who regularly used permanent hair dye in the year prior to enrolling in the study were 9% more likely than women who didn’t use hair dye to develop breast cancer. Among African American women, using permanent dyes every five to eight weeks or more was associated with a 60% increased risk of breast cancer, compared with an 8% increased risk for white women [4].
Are Black women at higher risk specifically?
Yes, and this is one of the most consistent and concerning findings across multiple studies. Black women face a 45% increased risk compared to a 7% increased risk in white women, according to the NIH Sister Study [3]. A separate study found even sharper disparities by dye shade: use of dark hair dye shades was associated with a 51% increased breast cancer risk among African Americans, and a 72% increased estrogen receptor-positive (ER+) disease risk among African Americans specifically [7]. These findings exist against a broader backdrop of racial health inequity — breast cancer mortality rates are 40% higher in Black women compared to white women, though overall incidence rates are similar [5], and Black women are more likely to be diagnosed with aggressive tumor subtypes and to die after a breast cancer diagnosis [8].
Why might the risk be higher for Black women specifically?
There are several compounding factors. Researchers have found that certain hair care products marketed to Black women contain many endocrine-disrupting chemicals that may contribute to the higher associations of breast cancer. A 2016 EWG study of personal care products marketed to Black women found that fewer than one-fourth of those products were “clean” or had fewer potentially hazardous ingredients, compared to products marketed to the general public [9]. Additionally, in one major study, relaxer use was far more common among African American women (88%) compared to white women (5%), and deep conditioner use was 59% among African Americans compared to just 6% among white women [7] — meaning cumulative chemical exposure through hair care routines is substantially higher on average.
Does the type of product (dye vs. straightener/relaxer) affect risk differently across racial groups?
Research suggests the picture is complex and varies by product and race. In a large case-control study in New York and New Jersey, white women who had ever used chemical hair relaxers were 1.7 times as likely as nonusers to develop breast cancer, but no such association was seen in Black women [10]. By contrast, hair dye — particularly darker shades — showed stronger associations in Black women. Among African Americans, use of dark shades and higher frequency of use were associated with increased ER+ disease risk, while among white women, dual use of relaxers and hair dyes was associated with an odds ratio of 2.40 for breast cancer [7].
What chemicals in hair dye might be responsible?
Some examples of potentially harmful chemicals found in hair products include formaldehyde, lead acetate, and para-phenylenediamine (PPD) — known or suspected carcinogens. Phthalates, parabens, bisphenol A (BPA), and formaldehyde are also hormone-disrupting chemicals that have been used in hair products and can affect how estrogen acts in the body [1].
Does the type of dye (permanent vs. semi-permanent) matter?
It appears to. Research has found little to no increase in breast cancer risk for semi-permanent or temporary dye use [4], while permanent dyes have shown the most consistent associations across studies.
What about hair straighteners?
Straightener use in the 12 months before enrollment in the Sister Study was associated with an 18% higher breast cancer risk. More frequent use brought higher risk — those who used straighteners every five to eight weeks had a 31% higher breast cancer risk [3].
What is the official regulatory and scientific consensus?
The International Agency for Research on Cancer (IARC) with the World Health Organization (WHO) has determined that personal use of hair dye is not classifiable as to its carcinogenicity to humans. However, the IARC did find increased risk for hairdressers or barbers who are in more frequent contact with hair dyes, listing that sort of occupational exposure as probably carcinogenic [3].
What are researchers and advocacy organizations recommending?
The Breast Cancer Research Foundation launched a Health Equity Initiative in 2023 — “Breast Cancer Drivers in Black Women: Society to Biology” — geared toward understanding the intersection of social determinants of health, comorbidities, and the biology of breast cancer in Black women [11]. In the meantime, it is recommended to avoid or limit the use of chemical hair straighteners and hair dyes as much as possible, and using resources like their Campaign for Safe Cosmetics database to identify products with fewer hazardous ingredients [9].
Should I stop using hair dye?
More research is needed to figure out which chemicals or formulations in hair products are associated with breast cancer risk, and it is a difficult topic to study because there are so many different product formulations that keep changing over time [1]. That said, the evidence is stronger for concern among Black women, particularly heavy and long-term users of permanent dyes. If you have concerns — particularly if you are a Black woman or have a family history of breast cancer — speaking with your doctor about your overall risk profile is a reasonable step.
Bibliography
[1] Breastcancer.org. “Do Hair Dyes and Straighteners Increase Breast Cancer Risk?” October 13, 2023. https://www.breastcancer.org/risk/risk-factors/hair-straighteners-dyes-cancer-risk.
[2] Susan G. Komen. “Hair Dye and Breast Cancer Risk.” Updated June 10, 2025. https://www.komen.org/breast-cancer/facts-statistics/research-studies/topics/hair-dyes-and-breast-cancer-risk/.
[3] Cleveland Clinic. “Can Hair Dye Increase Cancer Risk?” October 25, 2023. https://health.clevelandclinic.org/hair-dye-and-breast-cancer-risk.
[4] National Institutes of Health. “Permanent Hair Dye and Straighteners May Increase Breast Cancer Risk.” NIH News Release. https://www.nih.gov/news-events/news-releases/permanent-hair-dye-straighteners-may-increase-breast-cancer-risk.
[5] National Cancer Institute, Division of Cancer Epidemiology and Genetics. “Breast Cancer Risk Prediction for Black Women.” January 30, 2024. https://dceg.cancer.gov/news-events/news/2024/prs-black-women-breast-cancer.
[6] Schernhammer, Eva, et al. “Hair Dye and Cancer Risk: Largest Study Yet.” ecancer, September 4, 2020. https://ecancer.org/en/news/18603-hair-dye-and-cancer-risk-largest-study-yet.
[7] Llanos, Adana A. M., et al. “Hair Product Use and Breast Cancer Risk Among African American and White Women.” Carcinogenesis 38, no. 9 (2017): 883–892. https://pmc.ncbi.nlm.nih.gov/articles/PMC5862263/.
[8] Eberle, Claire E., Dale P. Sandler, Kyla W. Taylor, and Alexandra J. White. “Hair Dye and Chemical Straightener Use and Breast Cancer Risk in a Large US Population of Black and White Women.” International Journal of Cancer 147, no. 2 (2020): 383–391. https://pmc.ncbi.nlm.nih.gov/articles/PMC7246134/.
[9] Environmental Working Group. “Study Links Hair Dye and Chemical Straighteners to Breast Cancer, With Risk From Dye Highest for Black Women.” https://www.ewg.org/news-insights/news/study-links-hair-dye-and-chemical-straighteners-breast-cancer-risk-dye-highest.
[10] National Cancer Institute. “Hair Products and Cancer Risk.” https://www.cancer.gov/about-cancer/causes-prevention/risk/substances/hair-dyes-fact-sheet.
[11] Breast Cancer Research Foundation. “Black Women and Breast Cancer: Disparities and Research.” Updated February 2025. https://www.bcrf.org/about-breast-cancer/black-women-breast-cancer-disparities/
