For many men and women, visits to hairdressers or barbershops to touch up their hair with dyes were affected by the arrival of the new coronavirus pandemic (SARS-CoV-2).
This led many to start dyeing at home, reviving an old fear surrounding this practice – can hair dye increase cancer risk? Let’s see what science says.
Although home dyeing makes it difficult to get close to a precise number, an estimated 1 in 4 women over the age of 20, 2 in 3 over the age of 45, and 1 in 10 men use hair dye. These can be broadly classified into three groups:
- Permanent or oxidizing.
The latter comprise approximately 80% of the products currently on the market. They consist of colorless “intermediate” dyes (chemicals called aromatic amines) and dye “couplers,” according to the National Cancer Institute (NCI).
In the presence of hydrogen peroxide, intermediates and couplers react with each other to form pigment molecules. Darker colors are formed by using higher concentrations of these intermediates.
Semi-permanent and temporary hair dyes are non-oxidative and include color compounds that directly color the hair.
It is estimated that more than 5000 different chemicals can be found in hair dyes, some of which, according to various investigations, are carcinogenic in animals.
This characteristic would be responsible for the fact that in recent years the link between these products with an increased risk of cancer in people has spread.
- Home remedies for various hair problems
Other factors were also influential, such as the associations that population studies showed between an increased risk of bladder cancer among hairdressers and barbers.
Although many of the harmful components have been changed by hair color manufacturers in the last 50 years, it is not known for sure whether some of the chemicals that are still used can cause cancer.
Typically, it was common to find the following substances in permanent hair dyes:
- Toluene diamines.
- Other aromatic amino compounds.
Harmful substances in temporary dyes used to be:
- Denatured alcohol.
A common risk associated with hair dyes is intoxication, which occurs when someone swallows or inhales the dyes for long periods of time. This can cause:
- Difficulty breathing.
- Abdominal pain.
- Burning sore throat
- Redness in the eyes.
- Low blood pressure.
- Trouble walking normally.
- Blurry vision.
Hair dyes and cancer
In recent years, much research has been devoted to studying the relationship between personal or home use of hair dye and the risk of cancer or cancer-related death.
However, the results have been characterized as contradictory. Experts note that this can be due to many factors:
- Inadequate classification of dye exposures.
- Inadequate classification of the type of hair dye used (permanent or non-permanent).
- Poor accounting for specific cancer risk factors, beyond the permanent use of hair dye.
- Small study populations.
There are other work, such as the one published in The BMJ by researchers from Harvard Medical School, who evaluated the relationship between personal hair dye use and the risk of cancer and cancer-related death.
To do this, they compared information from more than 117,000 women enrolled in the Nurses’ Health Study, collected over 36 years. They looked at many factors, such as:
- Natural hair color.
- Risk factors for specific types of cancer.
- Body mass index.
- Health problems, such as smoking or alcohol use.
- Use of dye: differentiating the type of dye, as well as recurring users, spontaneous users or those who never used.
Compared to people who did not use dye, participants who had ever used permanent hair dyes did not have an overall higher risk of cancer or cancer-related deaths.
If a slightly higher incidence of specific cancers, such as basal cell carcinoma (the most common type of skin cancer) was found among users who ever used dyes versus those who never did.
The authors noted that more studies are still needed to better understand this association, although they noted that these types of links do not prove causation.
For now, personal use of permanent hair dyes does not appear to increase the risk of most cancers or cancer-related death.
Many experts point out that this is an encouraging figure, although it is necessary to continue deepening in aspects related to its safety.
Until new studies emerge, specialists advise taking personal and family history into account before using permanent hair dyes.
If there is any doubt about the effects this may cause, consult a doctor or dermatologist for more information.
Until there is significant scientific evidence from human trials, people interested in using herbal therapies and supplements should exercise extreme caution.
Do not abandon or modify your medications or treatments, first talk to your doctor about the potential effects of alternative or complementary therapies.
Remember, the medicinal properties of herbs and supplements can also interact with prescription drugs, other herbs and supplements, and even alter your diet.
Sources consulted: US National Library of Medicine, Mayo Clinic, Harvard Medical School, National Cancer Institute.