What you must know about hair dyes and cancer


It is a fact that hair colour products contain strong chemicals, but can they cause cancer?

It’s a non-negotiable part of your beauty routine: every two months you book in at the hairdresser to get rid of your unsightly greying roots.  But rumours that hair dye may up your cancer risk are making you nervous. Should you be worried? The risk associated with hair dye seems to depend on the type of hair dye used, as well the frequency of exposure.According to the US National Cancer Institute, there are three types of hair dyes:

1. Temporary hair dyes that don’t penetrate into the hair shaft and only last one or two washes (many people use these hair dyes for one-off occasions such as fancy-dress parties).

2. Semi-permanent dyes that do penetrate into the hair shaft, but which wash out in 5 to 10 washes.

3. Permanent hair dyes, which are used most frequently and which cause the most concern. These also penetrate into the hair shaft, and the colouring agents (which contain chemicals called aromatic amines and dye couplers that form pigment molecules when mixed with hydrogen peroxide) contain a wide variety of chemicals. In the 1970's these chemicals were reported to cause cancer in animals, but, according to the American Cancer Society, hair dye manufacturers have changed the ingredients of their products.

Two groups studied

Many studies have been conducted to see whether there’s a link between exposure to the chemicals in hair dyes and the development of certain cancers, including bladder cancer, leukaemia, lymphoma and breast cancer.Two groups of people have been studied in the past: those who have their hair dyed every few weeks, and hairdressers and barbers who are exposed to these chemicals on an ongoing basis.A meta-analysis published in Occupational and Environmental Medicine (May 2010), which included 42 studies, did show an increased risk for bladder cancer among hairdressers, particularly in those who held their jobs for 10 or more years.

But the researchers cautioned that the results were possibly influenced by whether the hairdressers smoked or not. The aromatic amines that were used in hair dyes and other hair products until the end of the 1970s, but banned thereafter, could also have played a role in hairdressers whose careers spanned many decades.Another meta-analysis from the same source showed a slight increased risk for lung cancer, larynx cancer, and multiple myeloma among hairdressers.But the increased risk of cancer among users of hair dyes seems to be extremely slight, and then only in women who began using hair dyes before 1980, when they still contained some potentially harmful carcinogens.

The good news is that there’s no increased risk among recent users.

Read more: Does hair dye cause cancer?

A few questions on the safety of hair dyes:

Can I dye my hair while I’m pregnant?

Yes, you can dye your hair while you’re pregnant, It's recommend you wear gloves if you’re doing it yourself, dyeing your hair in a well-ventilated room, and leaving the dye on for the minimum amount of time. There are simply not enough chemicals in hair dyes to do any harm to you or your baby.

How do I find out if I’m allergic to hair dye?

An allergic reaction can vary from skin irritation in areas of direct contact, to a systemic reaction such as urticarial or widespread itching, according to Allergy UK. A patch test at an allergy clinic could help identify the culprit in your case. Non-permanent dyes may be safer for regular use if you have a reaction to the stronger chemicals in permanent hair dyes.

Should I keep any other safety tips in mind when colouring my hair?

The FDA recommends the following:

- Follow the directions on the package.

- Do a patch test to test for allergies.

- Wear gloves.

- Don’t colour your eyebrows or eyelashes yourself with hair dye.

- Rinse your scalp well after using hair dye.

Read more:

Does hair dye cause cancer?

Certain hair dyes banned in Europe

Risk factors for cancer


The US National Cancer InstituteAmerican Cancer Society; Pregnancy Birth and BabyAllergy UKUS Food and Drug Administration 

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