Does Hair Dye Cause Cancer? New Study Raises Concerns - Dr. Axe

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Does Hair Dye Cause Cancer? New Study Raises Concerns


Does hair dye cause cancer - Dr. Axe

Does hair dye cause cancer? Let’s just say if you’re one to touch up your locks every month or so, you may be shocked to read about the scary connection researchers just discovered.

The results of a new study suggest the risk of breast cancer increases with more frequent use of chemical hair products, including permanent hair dye and hair straighteners.

For women using permanent dyes every five to eight weeks, for instance, the risk of breast cancer increases by about 60 percent in African American women and eight percent in white women.

Researchers suggest that although it’s unlikely the use of chemical hair products alone will determine a woman’s risk of breast cancer, avoiding these chemicals may beneficial. It’s one more way a woman can reduce the risk of becoming one of the one-in-eight women who develop breast cancer in the United States.

Does Hair Dye Cause Cancer: Study Takeaways

A study published in December 2019 in the International Journal of Cancer found that women who use permanent hair dye regularly were 9 percent more likely to develop breast cancer than those who didn’t use these products.


The study used data from the Sister Study. It looked at 46,709 women ages 35 to 74 who had a sister with breast cancer, but who were breast cancer-free themselves. The Sister Study, conducted by the National Institute of Environmental Health Sciences, sought to find causes of breast cancer by studying the environment, genes and experiences of breast cancer patients and their sisters.

The questionnaires given during study enrollment asked for hair product uses in the past 12 months. During the study follow-up, which was a mean of 8.3 years later, 2,794 breast cancer cases were identified.

Here’s what researchers learned from the data based on hair product use:

  • Permanent dye use was associated with a 45 percent higher breast cancer risk in black women and a seven percent higher risk in white women.
  • The risk of breast cancer increased among women who use permanent hair dye more frequency (every five to six weeks or more), especially among African American women
  • Women who used personal straightener products had a higher breast cancer risk, and the more they used the products the greater the risk.
  • Women who used hair straighteners at least every five to eight weeks faced about a 30 percent higher risk of  developing breast cancer.
  • Nonprofessional application of semipermanent dyes and straighteners was not associated with a significant increase in breast cancer risk.

As you can see from the study data, women of color were much more impacted by chemical hair products than white women. Researchers can’t explain this disparity, but in the questionnaire, researchers asked participants what type of hair products they used. Because black and white women tend to use different types of hair products, that may be a factor.

Darker hair dyes often contain more chemicals, so they may be of greater concern, too.

Some may argue that these findings may not give us a clear understanding of how chemical hair product use is linked to breast cancer risk, as the participants in the Sister Study have a family history of breast cancer. But this data highlights, at the very least, that environmental factors, like the chemicals we use on our bodies, can pose negative impacts on our health.

Does Hair Dye Cause Breast Cancer? Top 10 Concerning Chemicals in Hair Dye

According to researchers from the National Institute of Environmental Health Services, “many hair products contain endocrine-disrupting compounds and carcinogens potentially relevant to breast cancer.”

There are three types of hair dyes:

  • Temporary dyes that only cover the surface of your hair, but don’t penetrate the hair shaft
  • Semi-permanent dyes that do penetrate the hair shaft, but wash out after five to 10 washings
  • Permanent hair dyes that cause long-lasting chemical changes in the hair shaft

According to the American Cancer Society, permanent hair dyes contain colorless substances, including aromatic amines and phenols, that become dyes in the presence of hydrogen peroxide. A chemical reaction occurs, allowing the substance to permanently dye your hair until it grows out.

Environmental Working Group provides the following health risks of common hair dye ingredients:

  1. Ammonia: Respiratory irritant and potential endocrine disruptor
  2. Hydrogen peroxide: Respiratory and skin irritant; may burn skin, damage eyes and cause allergic reaction
  3. P-phenylenediamine: Potential carcinogen that causes organ system and blood toxicity; may cause allergies and immunotoxicity; causes occupational hazards
  4. Resorcinol: Potential endocrine disruptor and carcinogen that may cause allergies and immunotoxicity; contributes to occupational hazards, and may cause skin, eyes and lung irritation
  5. Toluene-2,5-diamine sulfate: Potential carcinogen and immunotoxic agent
  6. Methylisothiazolinone: May cause neurotoxicity, irritation and immunotoxicity
  7. Artificial fragrance: High potential for allergic reactions and immunotoxicity; potential cause of organ system toxicity
  8. Methylparaben: Potential endocrine disruptor and may cause biochemical or cellular level changes
  9. 1-Naphthol: Potential carcinogen; may cause immunotoxicity and irritation
  10. Ethanolamine: May cause organ system toxicity, irritation and allergic reactions

How do these chemicals work together to permanently dye your hair? First, ammonia (or ethanolamines when using an ammonia-free product) pulls apart the many layers of hair proteins, allowing for the dye to penetrate the hair shaft. Then hydrogen peroxide strips the hair and helps coloring agents, like p-phenylenediamine, to dye the hair.

Many of the dyes found in permanent hair dyes are called coal tar dyes and are usually formed as a by-product of hydrocarbon solvents. During the combustion or burning of coal, a thick brown-black liquid is generated. This chemical material is then used in cosmetic ingredients as dying agents, although they are known to have carcinogenic effects.

The Concern Over Straighteners

Researchers found that chemical relaxer and straightener products may contain hormonally-active compounds. The association between straightener use and breast cancer was similar among black and white women, but the data indicates that these products are more commonly used by black women.

The most problematic ingredient in hair straighteners, like the keratin treatment or Brazilian blowout, is formaldehyde. It’s a known carcinogen and may increase your risk of getting cancer, even at low levels that don’t cause noticeable symptoms.

Just smelling formaldehyde can cause irritations to your throat, eyes and nose — sometimes causing nose bleeds, a cough or sore throat. If this is your body’s response after smelling the chemical, imagine what happens when it’s applies directly to your hair and scalp?


Formaldehyde also impacts the central nervous system, leading to mood changes, insomnia, memory impairment and headaches.

And if you think you’re safe when using formaldehyde-free treatments, that may not be the case. Formaldehyde-free versions usually contain methylene glycol, which actually releases formaldehyde when it’s heated. Considering a hair iron at 450 degrees or higher is used during the hair straightening process, it seems like even formaldehyde-free options are dangerous.

Natural Alternatives

1. Use Natural Hair Lighteners

Instead of stripping your hair with hydrogen peroxide, try using ingredients that lighten your hair naturally. Some totally safe and surprising ingredients that you can use to lighten your hair include:

  • Chamomile
  • Baking soda
  • Lemon
  • Raw apple cider vinegar
  • Sea salt

Generally, applying any of these ingredients to your hair and leaving it on for 20 to 60 minutes will help to lighten your hair without the danger of hydrogen peroxide.

2. Cover Grays or Go Darker With Henna

Henna powder is a safer, more natural alternative to permanent hair dye. Henna is a pure plant dye, so it doesn’t contain any chemicals. Of course, you’ll want to purchase henna powder from a reputable company and read the ingredients carefully.

To use henna powder, it needs to be combined with a ½ cup or more of boiling water. Then allow the mixture to sit overnight. When you apply it the next day, let it sit for around two to three hours and then rinse well.

Be sure to wear gloves when working with henna, and avoid dying your skin by applying a barrier oil (like coconut oil) along your hairline.

Lush makes a range of colors and doesn’t test on animals. Just be sure to do a patch test to ensure that you like the color and you don’t experience any allergic or adverse reactions to the henna.

3. Go A Shade Darker With Coffee

Did you know that a cup of joe can serve as a natural hair dye for anyone looking to go a bit darker? It won’t have the same effects as permanent hair dye, but it will give your hair a little boost when you need it.

All you have to do is mix brewed dark-roast coffee with coffee grounds and any natural leave-in conditioner.

Apply your concoction to your clean, damp hair and let it sit for at least an hour. Then wash it out.

4. Use Natural Keratin Hair Products

Using natural shampoos, conditioners and hair masks with keratin can help to smooth your hair and make it easier to straighten. Keratin works to repair your hair, giving damaged strands a much smoother and healthier appearance.

There are a number of keratin hair products on the market. As always, go with a reputable company that values using natural, non-toxic ingredients. Check the EWG Skindeep database for safer options.

5. Try A Natural Deep Conditioner

Have you ever used natural, toxic-free oils in your hair to add shine and tame frizz? Argan oil and coconut oil are both hydrating and healing oils that can help to give your hair a smooth look and feel.

Simply warm about a teaspoon of either oil in the palm of your hands and then massage it into your hair and scalp. Put a shower cap on and sleep like that for the night. In the morning, wash your hair as usual.

Final Thoughts

  • Based on data collected in the Sister Study, researchers found a connection between permanent hair dye use and increased breast cancer risk. Hair straightening is also been linked to breast cancer development.
  • Researchers found that African American women who dyed their hair every five to eight faced the highest risk of breast cancer.
  • Emerging findings suggest chemical hair products do play a role in cancer risk, but we know that this isn’t the only factor that contributes to a person’s risk.
  • Avoiding hair products that are made with toxic chemicals, especially permanent hair dyes and straighteners, is surely one way you can work to reduce your risk of breast cancer.

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