Since I was a kid, I’ve always been fascinated with hair dyes and have always dreamed of having my hair dyed purple. However, I’ve always heard people say that hair dye is very bad for one’s hair but I’ve never really thought about the chemistry behind it. So my question is: to what extent is hair dye safe for us to use?
In order to fully understand how hair dye works, I first asked myself: how exactly does hair colouring work? Hair colouring works when chemical reaction occurs between the hair molecules and pigments with peroxide and ammonia found in the hair dye itself. When dyeing hair, the cuticles found in the outer layer of the hair must first be opened with ammonia in order for the hair colour to be able to penetrate into the cortex of the hair. After the cuticles are open, there’s usually a two-step process that happens simultaneously, removing the original pigments in the hair using peroxide and depositing in couplers, which are chemical compounds that define the colour of the hair dye. Lastly, conditioners are use to close off the hair cuticles to seal in and protect the new colour. (Helmenstine, 2013)
Even though the first commercial and “safe” hair dye was produced in 1909 and over 75% of American women dye their hair, but to what extent is hair dye safe for us to use? Studies have shown that there’s a strong positive correlation between older hair dyes and cancer as the old compounds that made up the couplers were carcinogenic. However ever since they were identified, companies have altered the compounds for these couplers and they are no longer a problem anymore. But since then, new studies have also emerged showing that the new dyes may be indirectly causing cancer too. Researchers have found out that chemicals called secondary amines, which are found in all permanent hair dyes, are able to penetrate into our skin and hair, and remain there for up to years after the dyes are applied. Over time these secondary amines could react with tobacco smoke, exhaust fumes, or other substances to form a highly poisonous chemical known as N-nitrosamines. (Brown Girl, 2013)
At the same time, hair dye is known to irritate the skin and cause skin discolouration due to the fact that our skin is also made up of the same type of keratinized protein as hair. However, this discolouration typically disappears within a few days as the skin naturally renews itself. Hence, a good way to prevent the discolouration of the skin is to apply a thin layer of petroleum jelly and wear latex gloves to protect the hands. (Wikipedia, 2013)
In conclusion, although the old hair dye problems have been solved, new problems are still arising and shouldn’t be ignored. So to be on the safe side, one can use hair dye, but just use it with caution, and don’t apply it regularly as it allows the build up of these secondary amines.
– Helmenstine, A. M., & Ph.D.. (n.d.). Hair Color Chemistry – How Haircoloring Works. About.com Chemistry – Chemistry Projects, Homework Help, Periodic Table. Retrieved September 1, 2013, from http://chemistry.about.com/cs/howthingswork/a/aa101203a.htm
– Hair coloring – Wikipedia, the free encyclopedia. (n.d.). Wikipedia, the free encyclopedia. Retrieved September 1, 2013, from http://en.wikipedia.org/wiki/Hair_coloring
– Amine – Wikipedia, the free encyclopedia. (n.d.). Wikipedia, the free encyclopedia. Retrieved September 1, 2013, from http://en.wikipedia.org/wiki/Amine
– Nitrosamine – Wikipedia, the free encyclopedia. (n.d.). Wikipedia, the free encyclopedia. Retrieved September 1, 2013, from http://en.wikipedia.org/wiki/Nitrosamine
– Column of Controversy: Hair Dye vs. Cancer | Brown Girl Magazine. (n.d.). Brown Girl Magazine | The Premier Magazine for Young South Asian Women. Retrieved September 1, 2013, from http://browngirlmagazine.com/2013/05/column-of-controversy-hair-dye-vs-cancer/