Thousands of people across the world dye their hair; dating back all the way to 3400 B. C. when “people used extracts from plants or minerals that contained pigments like those of henna or black walnut shells”(“History & Future Discovery of Hair Dye. “). In 1932, hair dye was refined to create chemical reactions in the hair to change the natural structure and color of hair. Cosmetologists are near a plethora of chemicals every day that include carcinogens and mutagens they would never suspect.
People who use products to color hair should know what hemicals that are in the product, how they work and the risks they give to people who do not use these products according to directions. Hair is made up of three different proteins, keratin the same protein found in nails and skin pheomelanin and eumelanin. The ratio and quantities of pheomelanin and eumelanin create the natural color of someone’s hair. “Pheomelanin is responsible for blond, red and ginger colors while eumelanin is responsible for black and brown colors.
The absence of either type of melanin create white or gray hair colors”( Helmenstine). Hair has overlapping cells that become rogressively imbricated with continued growth, which are rich in cysteine. Chemicals in hair coloring products have functions that first, prepare the hair to accept the dye by opening up it’s cuticle, the outer layer of the hair shaft. Next, they alter hairshaft biology in the cortex of the hair to maximize the color change by removing the old color, melanin. Then, minimizing chemical damage to the hair shaft by replacing the meanin with a similar structured aromatic amine. Finally, the chemicals set the dye to make the color change permanent until the dyed hair is shed in the normal cycling of hair growth.
Common chemicals in these products include hydrogen peroxide which is known to be a bleaching agent and ammonia which makes the fibers in the hair swell for better acceptance of the dye. These two chemicals are crucial to permanent hair dye because of their functions and their part in oxidizing melanin. The oxidation of the protein melanin by hydrogen peroxide is an exothermic redox reaction.
It is performed under basic conditions created by ammonia, which is present in a powdered compound when bleaching hair or in a bottle or tube of hair dye that onsists of a mixture of aromatic amines, aromatic nitro derivatives, and phenols is added to the hydrogen peroxide, known as developer. There are two reactions that take place when coloring hair, the first is NH3 + 2(H2O2 ) NH3 + 2(H2O) + O2 which is mixed immediately before Then, NH3 + H2O + 18(O2 18(CO2 ). “Ammonia, NH3 color to penetrate the cortex of the hair. It also acts as a catalyst when the permanent hair color comes together with the peroxide”(Helmenstine).
Peroxide is used as an oxidizing agent, in which case, removes preexisting color and breaks chemical bonds, such as the disulfide bonds in air. As the melanin is decolorized, the new permanent color is bonded to the hair cortex. Oxidation dyes, permanent dyes, are primarily aromatic compounds which belongs to three major chemical families aminophenols (amino naphthols), diamines and phenols or naphthols. These oxidation dyes are then categorised under two groups, oxidation base (primary intermediate) and it’s coupler (secondary intermediate).
“Many of the organic aromatic amines used in hair dyes are strong sensitizers and oxidative dyes should be used with extreme caution”(Lansdown). Hair dye’s most common xidation base, paraphenylenediamine (C6H8N2 takes the place of the melanin in the hair shaft, giving it the physical properties of healthy hair )+ C18H10N2O4 , is the alkaline chemical that opens the cuticle and allows the hair (melanin) 3(NH3 ) + 4(H2O) + 2(O2 ), is very similar in structure to melanin and such as color, shine and strength. Mixed with resorcinol for example, the oxidation base and it’s coupler will create a specific color, in this case, a greenish brown. Some more examples of oxidation bases include aromatic amines paminophenol, 1naphthol, and 4amino2hydroxytoluene.
Couplers can also include propylene glycol, ethanol, glycerin. There are many more chemicals that can be substituted to create many different colors, these are just a aromatic amines and couplers that are found more often than others in hair dye packages. Researchers have been studying a possible link between hair dye use and cancer for many years showing risks “causing of blood cancers such as nonHodgekin leukemias and lymphomas, bladder cancer and breast cancer”(Rivas). Researchers use 2 main types of studies to try to figure out the main carcinogen including test animals and humans.
Researchers may also expose normal cells in a lab dish to the substance to see if it causes the types of changes that are seen in cancer cells. In most cases, neither type of study provides enough evidence on its own, so researchers usually look at both participant and subjectbased studies when trying to figure out if something might cause cancer. Aromatic amines, oxidation bases have been shown to cause cancer in test subjects, usually when fed large amounts of the dyes over a long period of time.
Many of the aromatic amines called toluidines have been implicated in causing cancer, but orthotoluidine has actually een confirmed as a carcinogen and has been banned from being used in hair coloring. “The effect of benzidine on a strain of female rats sensitive to the induction of mammary tumors, a cumulative dose of about 12 mg/rat gave 50% mammary tumors”(Ames, Kammen, Yamasaki). Another type of study looks at cancer rates in different groups of participants, which compare the cancer rate in a group exposed to a substance to the rate in a group not exposed to it, or compare it to what the expected cancer rate would be in the general population.
Sometimes it an be hard to know what the results of these studies mean, because many other factors that might affect the results are hard to account for. Hairdressers, barbers and beauticians represent an important occupational group, with greater than 800,000 people employed in the USA. “These professionals are exposed to thousands of chemicals contained in colorants, bleaches, shampoos and hair conditioners everyday. Several of these chemicals, essentially those contained in hair dyes, are potentially carcinogenic and some of them have been found in the urine of osmetologists”(Takkouche).
In higher concentration and frequency than that of normal daily exposure, in addition to the fact that they may be exposed to carcinogens contained in other products than hair dyes, puts hairdressers, barbers and beauticians at higher risk of urinary cancer. These professionals can accidentally ingest these chemicals by not wearing the correct amount of protective gear and not thoroughly washing after applying hair dye. Participants and subjects both showed a rise in urinary cancer when ingesting dyes. It is reasonable to estimate hat a woman undergoing one hair dyeing (with about 4 g of amines) could absorb as much as 40 mg (1%) of hair dye chemicals (precursors, products, and side products) through the scalp.
Some studies have found an increased risk of certain types of nonHodgkin lymphoma in women who use hair dyes, especially if they began use before 1980 and/or use darker colors. The same types of results have been found in some studies of leukemia risk. A wide variety of carcinogens have been detected as mutagens after they have been metabolized to their active forms. In addition to a potential carcinogenicity, many of the ompounds that are mutagenic for bacteria may be hazardous to humans by causing mutations in the germline, DNA or RNA.
A molecule including either a frameshift mutation, a genetic mutation caused by a deletion or insertion in a DNA sequence that shifts the way the sequence is read or a basepair substitution, a type of mutation involving replacement of a single nucleotide base with another in DNA or RNA can be extremely dangerous to a person. The aromatic amines all require activation with microsomes for mutagenesis; this is characteristic of a variety of aromatic amine carcinogens.
Nitrocarcinogens, such as 2nitrofluorene mutate the bacteria without microsomal activation though, the bacteria contains nitro reductases which activate them. Many hair dye components such as, pphenylenediamine, 2,5diaminotoluene, and 2,5diaminoanisole become strongly mutagenic after oxidation by H2O2 gives a very strong mutagenic response with strain when sulfur is present, which is located in the hair. As mentioned before, it can be hard to know what the results of these studies mean, due to many other factors that might affect the results that are hard to account for.
Neither subjectbased or participantbased lab study provides enough evidence on its own to determine real threats to users. If the directions are properly followed there is a very low chance of someone contracting any of the aforementioned ailments. People have dyed their hair with these and even harsher chemicals for over a century. While experimentation still continues to be researched, safer, more effective methods of hair colorization are sure to arise in the future. In retrospect, many people who dye their hair and believe it would be a good idea to eave the for an extra thirty minutes to make the color look better, does not understand the background chemistry of hair colorization.
The knowledge of the oxidation of melanin by hydrogen peroxide and a chemical vehicle can help many while coloring hair by understanding it is important to only keep the dye in for the said amount of time and to wear protective . Pphenylenediamine covering. People who know the chemicals in hair coloring products, how they work and the risks they can lead to are bound to choose not to abuse the product, listen to the instructions and have a lower risk of getting hurt by any of the carcinogens or mutagens.
