You might have heard that using hair dyes can cause cancer, but is it true?
Scientists have been looking into this for many years but haven’t come to a conclusion yet. Some studies have suggested that certain ingredients in hair dyes have a link to an increased risk of cancer, while others have suggested there is no link.
It’s not just women dying their hair at home who would benefit from knowing this; hair care professionals are also exposed to a lot of dyes in the course of their job, and an increasing number of men are using dyes.
Types of hair dyes
The three major types of dyes are:
• Temporary dyes, which only last for one to two washings, covering the hair’s surface.
• Semi-permanent dyes, which can last for up to 10 washings.
• Permanent dyes, “coal-tar dyes”, or oxidative dyes which generally don’t get washed out. These are the most popular.
Cancer studies have focused on semi-permanent and permanent dyes because of certain ingredients they use, and darker dyes contain more of these ingredients. These two also penetrate the hair’s surface unlike temporary dyes.
What is in the dye?
Every brand uses a different mix of ingredients, and those ingredients have changed in the past hundred or so years. Thankfully, the FDA warned about the safety of an ingredient called 4-methoxy-m-phenylenediamine in the 1980’s, so we won’t find that in modern dyes.
The first commercial hair dye used paraphenylenediamine, a chemical created in 1909 by French chemist Eugene Schuller. His company was called the French Harmless Hair Dye Company, but you may know it by its more popular current name: L’Oreal.
The two famous chemicals in permanent dyes are hydrogen peroxide and ammonia. Hydrogen peroxide starts the coloring process for permanent dyes, and ammonia allows the dye to get into the cuticle. These two chemicals are combined at the last moment before applying the dye to allow them to react and give you long-lasting color.
Unfortunately, we don’t yet know which chemicals might be carcinogenic.
Some of the other most frequently used ingredients in modern dyes include:
What do the studies say?
In 2019 a study found that women who regularly used permanent hair dyes were 9% more likely to get cancer than women who didn’t. The study used data from 46,709 women over the course of one year.
Another study, in September of 2020, found no increased risk of cancer of the bladder, blood, brain, colon, kidneys, lungs, and immune system. This time they used data from 117,200 women over 36 years.
Unfortunately, the same study did show risks for the use of permanent hair dyes.
• There was a slight risk of skin cancer for women with lighter hair.
• There was also an increased risk of ovarian and breast cancer depending on the how much permanent dye women had been exposed to over their lives.
• Women with darker hair had an increased risk of getting Hodgkin lymphoma when using permanent dye. Darker dyes are more aggressive and might have higher concentrations of the carcinogenic ingredients.
These studies only looked at who was getting cancer but couldn’t study cause and effect. Observational studies like this are still important and need to be combined with clinical trials to figure out exactly which chemicals are dangerous, if any.
So should I stop using dark permanent hair dyes?
Scientists still haven’t come to any consensus on how dangerous hair dyes are. Some have said the results of this most recent study could be chance findings, and the study itself did not have the certainty to establish a relationship between the dyes’ ingredients and cancer.
Different brands also use different ingredients, so it’s hard to know what is at fault. Ethnicity also seems to be a factor, with African American women showing more risk in some studies. At the same time, many of those African American women used hair dyes more frequently than others in the study.
Scientists have said that it’s too early to suggest whether or not to avoid hair dyes, especially since they’re just one of the many factors that can contribute to cancer.
The America Cancer Society points out that there might be other reasons to avoid hair dyes, including allergic reactions, hair loss for some people, and pregnancy. Like with cancer, we don’t yet know enough about the effect of hair dyes during pregnancy to give any certain recommendations.
What else can I use?
Temporary and even semi-permanent hair dyes seem to be safe. There are also hair dyes that use vegetables, fruits, herbs, spices, and even coffee as ingredients, though they’re not as strong as permanent hair dyes. They might not only be more friendly on the environment, but on your wallet too