Table of ContentsView AllTable of ContentsIs Dyeing Your Hair Bad?ResearchEffect on Black WomenSafety
Table of ContentsView All
View All
Table of Contents
Is Dyeing Your Hair Bad?
Research
Effect on Black Women
Safety
The studies referenced in this article and in the majority of research on hair coloring are focused oncisgenderwomen. To remain consistent with research, “women” will be used throughout this article to refer to cisgender women.
An estimated one-third or more of women over age 18 and about 10% of men over age 40 use some form of hair dye.But when it comes to hair dye and cancer risk, is hair dye safe?
There is conflicting research on whether exposure to the chemicals used in hair dye is associated with an increased risk of cancer, but some recent studies have noted a potential link.
Whether or not dyeing your hair is bad can’t be answered without considering the many different factors.
Some of the more than 5,000 chemicals in hair products have been found to induce tumors in rats. Some also contain mutagenic (capable of causing a change in the DNA of a cell) andendocrine-disrupting(interfere with hormones) properties. Some chemical straighteners also containformaldehyde, which is acarcinogen(capable of causing cancer).
However, it isn’t always as simple as looking for formaldehyde ormethylene glycolon the product labels. Synonyms may be listed, such as:
Products may also contain chemicals that release formaldehyde when they are heated (such as when using a flat iron or blow dryer). These include:
Which Products Contain Formaldehyde?The United States Occupational Safety and Health Administration (OSHA) has identified some of the brand-name products that contain formaldehyde or create exposure through use, even though they do not list formaldehyde on their labels.
Which Products Contain Formaldehyde?
The United States Occupational Safety and Health Administration (OSHA) has identified some of the brand-name products that contain formaldehyde or create exposure through use, even though they do not list formaldehyde on their labels.
Small amounts of some chemicals may be absorbed through the skin or inhaled from fumes while dyeing your hair, having your hair dyed, or dyeing someone else’s hair.
Hairdressers and other professionals who regularly work around hair dyes may have a higher exposure to these chemicals than those who occasionally use hair dye for personal use.
Most research so far has not found a conclusive link between personal hair dye use and cancer but rather notes the potential.
The World Health Organization’s International Agency for Research on Cancer (IARC) has determined that chemical exposure at work for these professionals is likely carcinogenic (based onbladder cancerdata specifically). In terms of personal hair dye use, the IARC determined it can’t be classified as carcinogenic to humans, due to the lack of evidence from human studies.
The U.S. government’s National Toxicology Program (NTP) has not classified exposure to hair dyes as having (or not having) the potential tocause cancer, but has deemed some chemicals that are now or were previously used in hair dyes to possibly be human carcinogens.
Types of Hair Dyes
There are three main types of hair dyes:
What Researchers Know About Hair Dye and Cancer
Most of the studies examining a possible risk between hair dye and an increased risk of cancer have focused on specific cancers, such as:
These studies typically considered the potential effects on people who regularly use hair dye and/or people who work with hair dyes.
Some of these studies have shown an increased risk of certain cancers with personal hair dye use, but others have found conflicting results.
A 2020 study of over 117,200 women in the United States found an association between hair dyes and an increased risk of some cancers, including:
The study found no increase in risk for most cancers (other than the ones listed) or cancer-related mortality for personal users of permanent hair dyes.
Study LimitationsThis study had several limitations that might make the results difficult to generalize for the public at large. Most of the participants were White. In addition, all of the participants were nurses, which may make them more likely to use safety precautions effectively.
Study Limitations
This study had several limitations that might make the results difficult to generalize for the public at large. Most of the participants were White. In addition, all of the participants were nurses, which may make them more likely to use safety precautions effectively.
Hair Dye, Straighteners, and Breast Cancer
A 2019 study examined a possible link between breast cancer and hair dye and hair straighteners. The study included 46,709 women in the United States who had no history of breast cancer at the time of the study enrollment, but had at least one sister who had received abreast cancer diagnosis.
The study found that the women who regularly used permanent hair dye during the year prior to the study were 9% more likely to develop breast cancer than those who didn’t use hair dye.
Little to no increase in breast cancer risk was found for semi-permanent or temporary dye use, though an association with nonprofessional application of semi-permanent dye to others was noted. This risk increased with frequency of use.
Results in Black Women vs. White WomenThere was a large discrepancy in the findings for Black women versus White women. Any permanent dye use in the year before joining the study was associated with a 45% higherbreast cancer risk for Black women. This increased to a 60% higher risk for Black women who used hair dye at least every five to eight weeks, compared with an 8% increased risk for White women. The association was present for both light and dark-colored dye in Black women, while only light-colored permanent hair dye was associated with breast cancer risk in White women.
Results in Black Women vs. White Women
There was a large discrepancy in the findings for Black women versus White women. Any permanent dye use in the year before joining the study was associated with a 45% higherbreast cancer risk for Black women. This increased to a 60% higher risk for Black women who used hair dye at least every five to eight weeks, compared with an 8% increased risk for White women. The association was present for both light and dark-colored dye in Black women, while only light-colored permanent hair dye was associated with breast cancer risk in White women.
Straightener use in the year before the study was associated with an 18%higher breast cancer risk, while a 31% higher breast cancer risk was found for women who used straighteners at least every five to eight weeks.
A 2021 analysis that included 210,319 participants provided significant evidence to support that chemicals in permanent hair dyes increase the risk of breast cancer, but it did not find significant evidence of an increased cancer risk associated with the use of hair straighteners.
What Isn’t Known
Determining if the associations found between hair dye and cancer represent a risk—and to what degree—is difficult to determine with current research.
In addition to inconsistent findings between studies, the studies themselves often have limitations that could influence the results, such as:
The 2019 study on the association between hair dye, straighteners, and breast cancer found that the use of hair dye disproportionately increased the risk of breast cancer for Black women than for White women, particularly with regular use.
Toxicological assessments have found higher concentrations of estrogen and endocrine-disrupting compounds in hair products that are marketed toward Black women, which may contribute to the increased risk levels.
Research on hair dye and cancer risk has focused primarily on White women, making the results of most studies not applicable to Black women.
More research is needed into how these products impact the cancer risks for Black women.
Safety for Salon Professionals
To prevent exposure to formaldehyde, it’s best to use products that do not list formaldehyde, formalin, methylene glycol, or any of the other names associated with formaldehyde.
If these products are used, salon owners (and other employers) must comply with OSHA’s standards for formaldehyde and hazard communication.
If you are a hair professional using products that may contain formaldehyde or other potentially hazardous substances, take steps to protect yourself:
Safety With At-Home Dyes
Some safety tips for dyeing your hair at home include the following:
Safety for Those Recovering from Cancer
Hair dyes, perms, and other products that contain strong chemicals may damage your hair and/or irritate your scalp while you arerecovering from chemotherapy. It’s best to wait until at least six months after finishing chemotherapy to dye or perm your hair.
If you encounter a problem, talk to your healthcare provider about exposure risk.
Non-Toxic Hair Dye
Vegetable-based hair dyes are available, which may be an option for people who are concerned about the safety of traditional hair dyes. The color change is typically less drastic and fades sooner than with permanent dyes.
Some may include ingredients found in permanent dyes, so read the label before use.
Verywell / Jessica Olah
Summary
Some studies show a link between some types of cancers and the use of hair dyes and/or straighteners, though others have seen conflicting results.
Studies on this subject often have limitations, such as participant samples that include mostly White women. Research also shows an increased risk of cancer in Black women, especially with regular hair dye use.
Safety measures should be taken when using hair dye and straighteners, such as avoiding products with formaldehyde as much as possible, wearing gloves, and applying products in a well-ventilated area.
10 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Cancer Institute.Hair dyes and cancer risk.Eberle CE, Sandler DP, Taylor KW, White AJ.Hair dye and chemical straightener use and breast cancer risk in a large US population of black and white women.Int J Cancer. 2020;147(2):383-391. doi:10.1002/ijc.32738U.S. Occupational Safety & Health Administration.Hair salons - formaldehyde in your products.American Cancer Society.Hair dyes and cancer risk.Zhang Y, Birmann BM, Han J, et al.Personal use of permanent hair dyes and cancer risk and mortality in US women: prospective cohort study.BMJ. 2020:m2942. doi:10.1136/bmj.m2942National Institutes of Health.Permanent hair dye and straighteners may increase breast cancer risk.Xu S, Wang H, Liu Y, et al.Hair chemicals may increase breast cancer risk: a meta-analysis of 210319 subjects from 14 studies.PLoS ONE. 2021;16(2):e0243792. doi:10.1371/journal.pone.0243792Occupational Safety & Health Administration.Hair salons: facts about formaldehyde in hair products - protecting worker health.U.S. Food & Drug Administration.Hair dyes.Cancer Research UK.Using hair dye after chemotherapy.
10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.National Cancer Institute.Hair dyes and cancer risk.Eberle CE, Sandler DP, Taylor KW, White AJ.Hair dye and chemical straightener use and breast cancer risk in a large US population of black and white women.Int J Cancer. 2020;147(2):383-391. doi:10.1002/ijc.32738U.S. Occupational Safety & Health Administration.Hair salons - formaldehyde in your products.American Cancer Society.Hair dyes and cancer risk.Zhang Y, Birmann BM, Han J, et al.Personal use of permanent hair dyes and cancer risk and mortality in US women: prospective cohort study.BMJ. 2020:m2942. doi:10.1136/bmj.m2942National Institutes of Health.Permanent hair dye and straighteners may increase breast cancer risk.Xu S, Wang H, Liu Y, et al.Hair chemicals may increase breast cancer risk: a meta-analysis of 210319 subjects from 14 studies.PLoS ONE. 2021;16(2):e0243792. doi:10.1371/journal.pone.0243792Occupational Safety & Health Administration.Hair salons: facts about formaldehyde in hair products - protecting worker health.U.S. Food & Drug Administration.Hair dyes.Cancer Research UK.Using hair dye after chemotherapy.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
National Cancer Institute.Hair dyes and cancer risk.Eberle CE, Sandler DP, Taylor KW, White AJ.Hair dye and chemical straightener use and breast cancer risk in a large US population of black and white women.Int J Cancer. 2020;147(2):383-391. doi:10.1002/ijc.32738U.S. Occupational Safety & Health Administration.Hair salons - formaldehyde in your products.American Cancer Society.Hair dyes and cancer risk.Zhang Y, Birmann BM, Han J, et al.Personal use of permanent hair dyes and cancer risk and mortality in US women: prospective cohort study.BMJ. 2020:m2942. doi:10.1136/bmj.m2942National Institutes of Health.Permanent hair dye and straighteners may increase breast cancer risk.Xu S, Wang H, Liu Y, et al.Hair chemicals may increase breast cancer risk: a meta-analysis of 210319 subjects from 14 studies.PLoS ONE. 2021;16(2):e0243792. doi:10.1371/journal.pone.0243792Occupational Safety & Health Administration.Hair salons: facts about formaldehyde in hair products - protecting worker health.U.S. Food & Drug Administration.Hair dyes.Cancer Research UK.Using hair dye after chemotherapy.
National Cancer Institute.Hair dyes and cancer risk.
Eberle CE, Sandler DP, Taylor KW, White AJ.Hair dye and chemical straightener use and breast cancer risk in a large US population of black and white women.Int J Cancer. 2020;147(2):383-391. doi:10.1002/ijc.32738
U.S. Occupational Safety & Health Administration.Hair salons - formaldehyde in your products.
American Cancer Society.Hair dyes and cancer risk.
Zhang Y, Birmann BM, Han J, et al.Personal use of permanent hair dyes and cancer risk and mortality in US women: prospective cohort study.BMJ. 2020:m2942. doi:10.1136/bmj.m2942
National Institutes of Health.Permanent hair dye and straighteners may increase breast cancer risk.
Xu S, Wang H, Liu Y, et al.Hair chemicals may increase breast cancer risk: a meta-analysis of 210319 subjects from 14 studies.PLoS ONE. 2021;16(2):e0243792. doi:10.1371/journal.pone.0243792
Occupational Safety & Health Administration.Hair salons: facts about formaldehyde in hair products - protecting worker health.
U.S. Food & Drug Administration.Hair dyes.
Cancer Research UK.Using hair dye after chemotherapy.
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