Deborah deMoulpied “Does she or doesn’t she? Only her hairdresser knows for sure.” This famous Clairol hair dye ad ran in the 1950s and ‘60s—back when the biggest concern about hair coloring was whether anyone would notice.
Today, the concerns are far more, well, hair-raising. Specifically: Do hair dyes and other hair treatments, like chemical straighteners and relaxers, increase cancer risk?
Chemicals in Hair Dyes
Common chemicals found in hair dyes include:
Many of these chemicals are known irritants, allergens, or endocrine-disrupting compounds (EDCs) that can interfere with hormone function. Some are common contaminants, while others release formaldehyde—a known human carcinogen.
A History of Harmful Chemicals in Hair Products
In 1980, the FDA mandated warning labels for certain cancer-causing chemicals in hair products. In response, companies reformulated their products—but often replaced the banned ingredients with regrettable substitutions—chemicals that are just as harmful but remain unregulated. While many of these substances are suspected carcinogens, they have not yet been officially classified as such.
What Does the Data Say About Hair Dyes, Straighteners, and Cancer Risk?
Research results have been mixed over the years, in part because hair dye formulations and regulations have changed over time. However, some studies have raised concerns.
⭐️ WATCH NOW: Is Makeup Bad for You? Choosing Safe Cosmetics and Personal Care Products
Elevated Cancer Risk in Hair Salon Workers
Some research has focused on cancer risk among hair salon workers. In 2010, the International Agency for Research on Cancer (IARC)—part of the World Health Organization (WHO)—classified workplace exposure as a hairdresser or barber as “probably carcinogenic to humans.” This conclusion was based on studies linking salon work to bladder cancer.
For personal use, however, the IARC did not find sufficient human evidence to make the same classification. Yet, animal studies have shown that hair dye ingredients can act as potent carcinogens.
One reason hairdressers may face higher cancer risk is the chemical reactions that occur when hair dyes are mixed. While individual ingredients in permanent hair dyes may not be carcinogenic alone, their combination can create harmful byproducts.
(Beyond cancer, hairdressers are also at higher risk for occupational allergic rhinitis (nasal inflammation) and asthma due to their exposure to irritants and allergens.)
Cancer Risk and Frequency of Use
Studies have examined whether frequent and long-term use of hair dyes or straighteners increases cancer risk.
- A recent U.S. study found an association between hair dye and straightener use and breast cancer.
- The Sister Study—which followed over 46,000 women—reported that hair dye and hair straightener use were very common:
- More than 50% of participants reported using hair dye.
- Almost 75% of Black women reported using chemical straighteners in the past year.
- The study concluded that permanent dye and chemical straightener use were linked to higher breast cancer risk, especially in Black women.
Beyond breast cancer, research has also linked hair dyes and straighteners to uterine, bladder, prostate, ovarian, and certain types of non-Hodgkin lymphoma.
Types of Hair Dyes
Not all hair dyes are created equal. There are three main categories:
- Temporary Dyes: Coat the hair surface without penetrating the hair shaft. Lasts 1–2 washes. Many henna-based dyes fall into this category.
- Semi-Permanent Dyes: Penetrate the hair shaft and typically last 5–10 washes.
- Permanent Dyes: Cause long-lasting chemical changes to the hair shaft. These are the most common type (80%) and involve chemical reactions with oxidizing agents like hydrogen peroxide.
Dark permanent dyes contain higher concentrations of chemicals that, when mixed with an oxidizing agent, may pose a greater cancer risk.
How to Assess Your Personal Risk
Understanding toxicology risk can help guide safer choices:
Health Risk = Hazard × Exposure
- Choosing less hazardous ingredients reduces risk.
- Limiting exposure (e.g., dyeing hair less frequently) also lowers risk.
There are three primary exposure routes:
- Inhalation (breathing in fumes)
- Dermal absorption (through the skin)
- Ingestion (accidental swallowing)
While many assume skin absorption is the biggest concern, inhalation exposure is equally problematic—especially for hairdressers, who may avoid direct skin contact by wearing gloves but still inhale volatile organic compounds (VOCs) throughout their workday.
⭐️ READ NOW: Endocrine-Disrupting Chemicals (EDCs): What They Are & How to Reduce Your Exposures eBook
How to Reduce Your Exposure to Harmful Hair Product Chemicals
Do’s:
✅ Read labels carefully. Avoid products containing p-phenylenediamine (PPD), resorcinol, DMDM hydantoin, imidazolidinyl urea, hydrogen peroxide, and parabens.
✅ Ask your hairdresser about low-toxicity options.
✅ Opt for semi-permanent or temporary dyes instead of permanent dyes.
✅ Choose ammonia-free products. Ammonia is corrosive and releases VOCs that irritate the lungs.
✅ Follow instructions carefully.
✅ Do a patch test before using a new product.
✅ Protect yourself: Wear gloves and a mask; ventilate your space.
✅ Rinse your scalp thoroughly after application.
✅ Consider balayage or foil techniques to minimize scalp contact with dye.
✅ Use databases and apps to find safer products.
✅ Embrace your natural hair color—gray is trending!
Don’ts:
❌ Don’t use permanent and dark hair dyes.
❌ Don’t use chemical straighteners—especially if you’re young!
❌ Don’t leave dyes on longer than instructed.
❌ Don’t dye your hair too often.
❌ Never mix different brands of dye. Their ingredients may react unpredictably.
❌ Don’t apply dye to irritated or broken skin.
❌ Avoid dyeing eyebrows or eyelashes. These products are not designed for delicate eye-area skin.
Conclusion
While research on hair dye and cancer is ongoing, multiple studies raise red flags. The Anticancer Lifestyle Program recommends applying the Precautionary Principle: when in doubt, proceed with caution.
Ditching hair dye isn’t easy, but the COVID-19 lockdowns showed many women that they could embrace their natural hair—and feel powerful doing so.
Resources to Find Safer Hair and Personal Care Products:
- Mamavation – Best & Worst Hair Color Brands
- EWG Skin Deep Database – Look up products and ingredients (ewg.org/skindeep)
- Clearya – A free mobile app and browser extension to find safer products
- Think Dirty – Scan barcodes to check product safety
References
-
The Disturbing Truth About Hair Relaxers – The New York Times (2024)
https://www.nytimes.com/2024/06/13/magazine/hair-relaxers-cancer-risk.html -
Is There a True Concern Regarding the Use of Hair Dye and Malignancy Development? – National Library of Medicine (PMC)
https://pmc.ncbi.nlm.nih.gov/articles/PMC3543291/ -
Hair Color Chemistry Gets a Fresh Look – American Chemical Society (ACS)
https://pubs.acs.org/doi/10.1021/cen-09817-cover -
Hair Dyes, Other Hair Products, and Cancer Risk – National Cancer Institute (NCI)
https://www.cancer.gov/about-cancer/causes-prevention/risk/substances/hair-dyes-fact-sheet -
Some Aromatic Amines, Organic Dyes, and Related Exposures – International Agency for Research on Cancer (IARC)
https://publications.iarc.fr/Book-And-Report-Series/Iarc-Monographs-On-The-Identification-Of-Carcinogenic-Hazards-To-Humans/Some-Aromatic-Amines-Organic-Dyes-And-Related-Exposures-2010 -
FDA – Hair Dyes and Their Safety – U.S. Food and Drug Administration (FDA)
https://www.fda.gov/cosmetics/cosmetic-products/hair-dyes -
Risk of Cancer Among Hairdressers and Related Workers: A Meta-Analysis – PubMed (NCBI)
https://pubmed.ncbi.nlm.nih.gov/19755396/ -
Personal Use of Permanent Hair Dyes and Cancer Risk: Prospective Cohort Study – The BMJ
https://www.bmj.com/content/370/bmj.m2942 -
Hair Dye and Chemical Straightener Use and Breast Cancer Risk in a Large US Population – National Library of Medicine (PMC)
https://pmc.ncbi.nlm.nih.gov/articles/PMC7246134/ -
Hair Relaxer Use and Risk of Uterine Cancer in the Black Women’s Health Study – ScienceDirect
https://www.sciencedirect.com/science/article/abs/pii/S0013935123020327 -
Measurement of Endocrine-Disrupting and Asthma-Associated Chemicals in Hair Products Used by Black Women – ScienceDirect
https://www.sciencedirect.com/science/article/pii/S0013935118301518 -
Associations of Hair Dye and Relaxer Use With Breast Tumor Clinicopathologic Features – PubMed (NCBI)
https://pubmed.ncbi.nlm.nih.gov/34390715/ -
Use of Straighteners and Other Hair Products and Incident Uterine Cancer – PubMed (NCBI)
https://pubmed.ncbi.nlm.nih.gov/36245087/ -
Hair Dye Use and Prostate Cancer Risk: A Prospective Analysis – PubMed (NCBI)
https://pubmed.ncbi.nlm.nih.gov/34797564/ -
Personal Use of Hair Dye and Risk of Certain Subtypes of Non-Hodgkin Lymphoma – National Library of Medicine (PMC)
https://pmc.ncbi.nlm.nih.gov/articles/PMC4025953/ -
Use of Hair Products in Relation to Ovarian Cancer Risk – National Library of Medicine (PMC)
https://pmc.ncbi.nlm.nih.gov/articles/PMC8561257/ -
Hair Straightening Chemicals Associated With Higher Uterine Cancer Risk – National Institute of Environmental Health Sciences (NIEHS)
https://www.niehs.nih.gov/newsreleases/hair-straightening-chemicals-associated-with-higher-uterine-cancer-risk -
Hair Dye Use and Risk of Bladder Cancer – National Library of Medicine (PMC)
https://pmc.ncbi.nlm.nih.gov/articles/PMC3203248/ -
Permanent Hair Dyes and Straighteners May Increase Breast Cancer Risk – National Institute of Environmental Health Sciences (NIEHS)
https://www.niehs.nih.gov/newsreleases/permanent-hair-dye-and-straighteners-may-increase-breast-cancer-risk -
Hair Dye Ingredients and Potential Health Risks from Exposure to Hair Dyeing – National Library of Medicine (PMC)
https://pmc.ncbi.nlm.nih.gov/articles/PMC9214764/ -
Occupational Asthma, Rhinitis, and Contact Urticaria Caused by Oxidative Hair Dyes in Hairdressers – Annals of Allergy, Asthma & Immunology
https://www.annallergy.org/article/S1081-1206(13)00737-0/abstract -
Can Hair Dye Increase Cancer Risk? Sister Study Results – Cleveland Clinic Health Essentials
https://health.clevelandclinic.org/hair-dye-and-breast-cancer-risk -
Highlight Your Style: Balayage vs. Foil Hair Coloring Techniques – The Abode Salon
https://www.theabodesalon.com/post/balayage-vs-foil-which-technique -
Women’s Voices for the Earth: Salon Label Report – EXPOSED
https://womensvoices.org/wp-content/uploads/2023/03/Salon-Label-Report_EXPOSED.pdf -
Women’s Voices for the Earth: Beauty and Its Beast
https://womensvoices.org/wp-content/uploads/2014/11/Beauty-and-Its-Beast.pdf
