Does Hair Dye Cause Cancer?

In the late 1970s, certain aromatic amine chemicals were shown to cause cancer in rats. Soon after, hair dyes were reformulated to exclude these specific cancer-causing substances. That said, today’s hair dye manufacturers may still use thousands of chemicals in their products, some of which could cause cancer.

In 2018, the Food and Drug Administration (FDA) banned lead acetate-containing hair dye. But aromatic amines, also known as coal-tar products, are still available in the United States. Recognizing the risks, the FDA requires coal-tar packaging to contain a warning and directions for consumers to do a skin test before they dye their hair.

Europe and other countries went further to limit the use of questionable substances in hair dye. In 2006, the European Commission banned 22 hair dye chemicals with no safety data to support their use. Since that time, this list has grown to 181 chemicals.

Examples of possible cancer-causing ingredients you may find in hair dyes include:

• Arylamines: These chemicals are made from petroleum or coal products and include para-phenylenediamine and para-toluenediamine.
• Aminophenols: These include para-aminophenols and 4-amino-meta-cresol.
• Pyrazoles: These include 4,5-diamino pyrazole.
• Meta-substituted aromatic derivatives: These include m-phenylenediamine, meta-aminophenol, and resorcinol.
• Pyridines: These include 2-amino-3-hydroxypyridine.
• 1-Naphthol and hydroquinone: These are additional common chemical ingredients in hair dye.

Examples of hair colors of concern include HC Blue 2 and HC Yellow 5.

Why are more concerning hair dye ingredients not banned in the U.S.?

It’s often not practical to ban entire chemical classes or colors for hair dye because some can be safe for use in small amounts.

The manufacturing process of hair dyes also affects the amount of cancer-causing agents in the final product. Different manufacturing techniques can result in various cancer-causing contaminants.

Another problem with cancer-causing chemicals in hair dye is that the original ingredient changes into different substances after application. This is especially apparent in dyes that require hydrogen peroxide and ammonia for activation. The chemicals formed during application aren’t tested for cancer-causing risk.

Additionally, each person’s hair may react differently. This can result in unique cancer-causing chemicals for that person.

Hair dyes come in two forms that differ in how they change hair color and how long they last.

Oxidative (permanent) hair dye

Oxidative hair dye must be activated by mixing an oxidizing agent (developer), such as hydrogen peroxide, with ammonia and a coloring agent.

Ammonia opens the outer layer of your hair strand’s shaft. In the oxidation process, the hydrogen peroxide then enters your hair strand’s shaft and reacts with melanin, which allows it to bond the coloring agent to your hair shaft. This permanently changes your hair color.

Oxidative hair dyes have more chemicals than nonoxidative ones. As a result, they’re stronger and more likely to irritate your scalp, especially if you have sensitive skin. This creates an entry point for the dye to get into your body.

If some chemicals are carcinogens, the risk of cancer is higher with oxidative hair dyes because they’re more easily absorbed through irritated skin into your bloodstream.

Nonoxidative (semipermanent and temporary) hair dye

Nonoxidative hair dye doesn’t use a developer. Instead, it simply coats or stains your hair strand’s shaft. Because this type of dye can’t remove natural hair pigments, it can only darken your hair and not lighten it.

There are two types:

• Semipermanent: These dyes move a short distance into your hair strand’s shaft. It washes out after a few weeks or about five washes.
• Temporary: These dyes are designed to disappear after one wash. Examples are Halloween spray color and hair chalk.

Bleach vs. dye

Both bleach and permanent hair coloring involve an oxidation process, but hair dye changes your hair color while bleach lightens it.

Semipermanent and temporary hair dyes don’t have oxidizing agents, so they can’t lighten your natural hair color.

The more you’re exposed to a cancer-causing chemical, the more likely you are to develop cancer. Factors related to the amount of exposure you have to the chemicals in hair dye include the following:

Hair dye cancer risk factors

• Exposure type: People who work with hair dye for a living, such as hairstylists and barbers, have a lot more exposure than people who get their hair dyed.
• Length of use: People who started dyeing their hair before hair dyes were reformulated in 1980 have been exposed to more potential carcinogens than those who started later.
• Frequency: The more often you dye your hair, the more you’re exposed to its chemicals.
• The color of the hair dye: Dark hair dye colors, such as black and brown, contain more chemicals that might be carcinogenic than light colors.
• Genetics: Hair dye that is absorbed into your bloodstream is broken down in your liver. People with slow liver-enzyme metabolism (slow NAT2 acetylation) may be more likely to develop bladder cancer.

The most extensive study on hair dye and cancer was published in 2020 and included 117,200 women older than 36 years of age. The researchers found that the general use of hair dye didn’t increase the women’s risk of cancer.

At the same time, study results showed long-term use and frequent use of hair dye increased the user’s risk of the following:

• estrogen receptor-negative breast cancer
• progesterone receptor-negative breast cancer
• hormone receptor-negative breast cancer
• ovarian cancer

Furthermore, the risk of Hodgkin’s lymphoma was seen only in women with naturally dark hair, and those with naturally light hair showed an increased risk of basil cell cancer.

The authors of the 2020 study caution that their study was limited because 96% of the women were of European ancestry.

Blood cancers

According to the American Cancer Society, some studies have suggested hair dyes slightly increase the risk of non-Hodgkin’s lymphoma and leukemia in women, especially if they started dyeing their hair before 1980 or use darker dye colors.

In a 2017 review of 33 studies, certain factors increased a person’s chance of developing leukemia. The factors included the type of hair dye, the person’s sex, and length of use. The authors said that the risk of developing blood cancer from personal hair dye use wasn’t likely when all the study data were combined.

A 2019 review of available studies also suggests a slight increase in the risk of non-Hodgkin’s lymphoma in women who use hair dye. These women are mainly those who have used it for 20 years or more.

Bladder cancer

Older studies have found a small increased risk of bladder cancer in people who worked with hair dye regularly. But the research isn’t conclusive because the studies include many people who started using hair color before 1980.

A 2014 review of all available studies provided strong evidence that using hair dye doesn’t increase your risk of bladder cancer.

Only one study has mentioned bladder cancer risk from hair dye since 2014. The 2020 Nurses Health Study showed no increased risk of bladder cancer during the 36-year study period. But the study results were limited to women of European descent, leaving the question of risk for other ethnic groups and sex.

Breast cancer

A review published in 2021 included 14 studies of breast cancer and hair dye ranging from 1978 to 2019. The review indicates that hair dye may increase a person’s risk of breast cancer, especially with permanent dyes. This was regardless of race, dye color, and breast cancer risk.

Results from the Woman’s Circle of Health Study in 2022 show home (or home plus salon) use of dye and relaxer may double the risk of breast cancer tumors, especially in Black women. The combination use of hair dye and relaxer also doubled the chance of a positive lymph node in people with estrogen receptor-negative breast cancer.

Adolescents 10 to 13 years old may also be at risk of future breast cancer from hair dye, according to a 2021 evaluation of a small subgroup enrolled in The Sister Study.

Although recent studies may show breast cancer risk with hair dye use, more research is needed.

Prostate cancer

One 2017 study found that the odds of getting prostate cancer for hair dye users was 2.15-fold more than that for nonusers. Other research has come to a similar conclusion.

A newer 2021 study has taken a more cautious approach, concluding that hair dye may increase the risk of prostate cancer. The authors believe these conclusions need to be supported by more research.

According to a 2020 study of 46,709 women, the use of permanent hair dye raised the risk of breast cancer by 45% in Black women as opposed to 7% in white women. The same study authors pointed out that hair products designed for Black women may contain more chemicals that negatively affect the endocrine system, specifically estrogen.

When permanent dye use was increased to every 5 to 8 weeks, it increased the risk of breast cancer in Black women to 60%. The study authors also noted that the use of hair straighteners is higher in Black women than in women who are white. This raises the chance that combining dye and straightener use increases breast cancer rates.

There may be a number of safer alternatives for dyeing your hair, but not all of them are as safe as they may seem. They may also not achieve the same result as regular hair dye.

They include:

Henna

Henna is a natural plant-based hair dye that lasts about 6 weeks. It’s considered semipermanent because it only stains the outer portion of your hair strand.

It’s possible to experience an allergy to henna, so you should always do a small skin test before you use it to color your hair. Don’t mix it with any other hair color products unless you’re sure they’re safe to use with henna, so you don’t damage your hair.

There’s also some limited, anecdotal evidence that frequently using henna can have some mild health side effects, such as more frequent colds or muscle aches.

Learn more about dyeing your hair with henna.

Organic (but not chemical free)

You can buy organic hair dyes, but they have to contain some chemicals to work. These chemicals are usually synthetic substances. Other natural ingredients may be easier on your hair.

Still, the FDA warns that these chemicals have the same potential to cause cancer as those in regular hair dyes.

Graphene

Graphene is the newest nontoxic hair dye alternative. Spraying or combing it into your hair leaves a coating of color.

Unlike hair dye, it doesn’t chemically damage your hair. It also lasts for over 30 washes. The disadvantage is that it only comes in black and brown.

Learn more about coloring your hair with graphene.

What hair dye is ok for cancer patients?

Experts recommend waiting to dye your hair until 6 months after finishing chemotherapy. Because your hair may grow back coarser and thinner after chemotherapy. Vegetable or henna dyes are the gentlest on fragile hair.

What other health effects can hair dye have besides cancer?

Besides the cancer risk, hair dyes frequently cause contact dermatitis and severe allergic reactions. Before using hair dye, a skin test (patch test) can help you determine if your product may cause a problem.

Which is safer? Salon or home hair dye?

Regardless of home or salon dye, the specific ingredients make it a higher risk. Permanent hair dyes have a higher risk than temporary dyes. Discussing the ingredients with your hairdresser or reviewing the ingredient list if you’re dyeing at home yourself is best.

The FDA recommends following package instructions and using gloves to increase home use safety.

Even after 40 years of research, more studies need to be done to evaluate the risk of hair dye use in the development of cancer.

The risk seems higher for:

• Black people assigned female at birth
• occupations that are exposed to hair dye, such as hairdressers or barbers
• use of both a straightener and dye together
• permanent hair dye
• dark hair dye
• frequency
• number of years dyeing
• use beginning in adolescence

It’s best to evaluate the risks and decide what’s safest for you.