Hair Dye Dangers: harmful chemicals in hair dye and other alternatives

Hair Dye Dangers: harmful chemicals in hair dye and other alternatives

Today, hair dyeing is a no newfound trend but is rather part of an aesthetic or a self-care ritual. Fun fact: Hair dye was accidentally created by William Henry Perkin in his attempt to generate a cure for malaria in 1863. However, do people even know what they put their hair through just to change its color?

The anatomy of hair

The hair strand (shaft) are made of three parts:

Medulla: this is the core of hair.

Cortex: the medulla is covered by a thick layer of cells containing keratin proteins, moisture and melanin, all of which contribute to our natural hair texture and color.

Cuticle: this is a protective layer which is made up of overlapping scales.

the structure of a hair shaft

The types of hair dyes

There are 3 major types of hair dyes:

Temporary dye:

Only sticks to the surface of the cuticle, and will be easily washed off with a shampoo wash.

Semi-permanent dye:

This dye is made up of tiny pigment molecules that slip by the cuticle and stick to the cortex of the hair. The dye will be washed off after multiple shampoo washes.

Permanent dye:

As they are made to last, permanent hair dye contain a lot of chemicals. In particular, alkaline chemicals such as ammonia breaks up the overlapping scale structure of the cuticle by softening them. Then a developer is used to oxidize the melanin in the cortex, turning it colorless. The developers also create the chemical reaction that brings in the new color to the hair. These new pigments are then trapped beneath the cuticle, and are resistant towards shampoo washes.

How are hair dyes regulated?

According to the US Food & Drug Administration (FDA), they cannot take action against hair dye corporations if the product contains harmful ingredients that are listed as warning labels. Coal-tar hair dyes in particular, do not need approval from the FDA as long as they have caution labels.

Fun fact: Although hair dye colouring materials are mostly from petroleum, FDA still keeps its original name (Coal-tar), which originated from the fact that colouring materials were by-products of coal industries.

The EU on the other hand, has more simple and strict regulations. As hair dyes are categorized as cosmetics, the manufacturer must be able to provide evidence of scientific assessment on the product, showing that substances used would not cause any harm to consumers. Currently, there are more than 180 ingredients banned in the cosmetic department.

Do hair dyes cause cancer?

We don’t exactly know. According to the American Cancer Society, the research on hair dye and it’s correlation to cancer is very mixed.

The International Agency for Research on Cancer (IARC) shows that workers who are exposed to hair dyes such as hairdressers and barbers have an increased risk of getting bladder cancer. However, the research also shows that there is no consistent increase of bladder cancer in people who personally uses hair dye.

The results of blood-related cancers are also mixed. The research shows that there is a higher risk of lymphoma in hair dye users, especially if the use began before the 1980s, or if the person uses dark hair dyes. However there are also contradictory results, hence, there is no definite answer.

The possible reason why darker hair dyes may increase the risk of blood-related cancer could be because they contain more coloring agents and carcinogen chemicals.

The National Toxicology Program also conducted research on hair dyes (and chemical straightener) and its possibility of being a carcinogen. They found that women who regularly use hair dye has a 9% more chance of contracting breast cancer compared to those who don’t use hair dye. Interestingly, black women who use permanent hair dye have a 60% higher chance of contracting breast cancer while white women has only 8%.

As suggested by Alexandra White, Ph.D., head of the NIEHS Environment and Cancer Epidemiology Group, “the dye that’s marketed to white women might be different than the dye that’s marketed to black women just because of the texture of the hair…maybe the application process is different, or the amount of dye that’s needed to be used is different.”

However the evidences is not credible enough to pinpoint that hair dye is a direct cause of breast cancer. Especially since the women that were experimented on had sisters who have breast cancer, doubling the chances of developing the cancer, “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.

Overall, to quote the conclusion of the research conducted by the IARC

“Cancer in humans:

  • There is limited evidence in humans for the carcinogenicity of occupational exposures as a hairdresser or barber.
  • There is inadequate evidence in humans for the carcinogenicity of personal use of
    hair colorants.”

“Overall evaluation:

  • Occupational exposures as a hairdresser or barber are probably carcinogenic to humans
    Personal use of hair colorants is not classifiable as to its carcinogenicity to humans”

Just as the IARC, the NTP have not classified hair dye as carcinogenic, however they have laid out other health affects and have named harmful chemicals in the product.

Harmful Chemicals in hair dye and it’s effects

Triclosan: Disrupts estrogen hormones. In 2017, the FDA declared Triclosan to be harmful. According to Clinical and Experimental Allergy, they found that children exposed to triclosan has an increased chance of asthma, allergies, eczema and rhinitis.

Ammonia: Ammonia irritates the skin, eyes, nose, throat, and lungs. In addition, this chemical damages the hair cuticle, leaving it dry, brittle and unhealthy.

P-Phenylenediamine (PPD): Many hair dye users who looks for alternative hair dye tends to look for Ammonia-free dyes. However, according to Dr Rohit Batra of
Dermaworld Skin & Hair Clinics, allergies and irritations still form as PPD is the real culprit.

Lead acetate: Commonly found in men’s hair dye, this chemical is harmful to skin contact, when inhaled, and is suspected of causing cancer, genetic defect and fertility problems. This substance has been prohibited by the European Commission for use in cosmetic products.

Toluene: This chemical not only can cause temporary effects such as headaches and skin irritations, but it can be linked to fertility and pregnancy problems and respiratory complications.

Advice: If you want to die your hair

If you’re looking to dye your hair a natural dark colour such as black, brown or burgundy. Stick to henna hair dyes! Henna works as a natural alternative to permanent hair dye. It doesn’t involve a chemical process but rather the natural pigment (lawsone) coats itself to the hair shaft, migrating through the gaps of the cuticle, binding itself to the keratin, making it resistant to hair washes.

Henna is also used to make beautiful body art

In addition, henna also gives the hair a lot of benefits. It protects the cuticles, keeping the hair healthy, moisturized, and prevents the hair from ageing. Just remember to be cautious of the henna you’re buying as it may have (PPD) or other harmful ingredients, look out for the ones that are 100% organic.

If you absolutely want a fresh hair color, opt for temporary or semi-permanent hair dyes. These dyes have less damaging ingredients and does not usually involve bleaching of the hair. A misconception is that staying with safe hair dyes means you cannot play with fun colors. However, temporary hair dye brands specifically formulate their dye to work with dark hair to achieve the vibrant look.


 “Hair Dyes | FDA.” 30 Oct. 2018, Accessed 19 Nov. 2020.

 “Good to know about hair dyes – ECHA.” Accessed 19 Nov. 2020.

“Hair Dyes – American Cancer Society.” Accessed 19 Nov. 2020.


“Cosmetics and Hair Dye – National Institute of Environmental ….” Accessed 20 Nov. 2020.

 “Permanent Hair Dye and Straighteners May Increase Breast ….” Accessed 20 Nov. 2020.

“Triclosan Exposure and Allergic Sensitization in Norwegian ….” 12 Nov. 2012, Accessed 20 Nov. 2020.

“Hair dye reactions : Causes, Diagnosis, Symptoms and ….” 2 Feb. 2020, Accessed 20 Nov. 2020.

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