It is estimated that one-third of the women above the age 18 and about 10% of the men above the age 40 use some type of hair dye. For years, hair dyes have been under a lot of speculation for their potent carcinogenicity.
Types Of Dyes
Hair dyes are divided into temporary, semi-permanent, and permanent depending on their action and longevity.
- Temporary hair dyes do not penetrate the hair shaft but cover the surface of the hair. They last for 1–2 washes.
- Semi-permanent dyes do penetrate the shaft and last for 5–10 washes.
- Permanent dyes are the most commonly used dyes and typically last until a new hair grows. These cause a permanent change to the biochemistry of the hair shaft. These consist of colorless dyes called intermediaries (aromatic amines) and dye couplers. In the presence of hydrogen peroxide, both of these react to form the pigment molecule which imparts color to the hair.
Hair Dyes And Carcinogenicity
Until The Late 1970’s
In the late 1970’s permanent hair dyes constituted of numerous chemicals that caused cancer in the animals. In response, regulatory changes were done to remove some of these harmful chemicals. However, the complete elimination of the same isn’t stated in any studies.1
Risk Of Bladder Cancer
Although the potent carcinogens were considerably reduced after the 1970’s, the presence of aromatic amines in these dyes is still prominent. The impact of these on the health of hairdressers and users was particularly tested, and results showed an increased risk of bladder cancer or urothelial cancer. This is due to the consistent exposure to the harmful compounds.2
Current epidemiological studies, however, do not show an increase in the risk of bladder cancer either in the hairdressers or the users.
Prone To Non-Hodgkins Lymphoma (NHL)
There have been conflicting results from the studies conducted on the personal use of permanent dyes and the risk of developing Non-Hodgkins Lymphoma (Cancer of the lymphatic system, where too many abnormal WBCs are produced).
A study was conducted and a pooled analysis was done on 4,461 women with NHL and 5,799 women who did not have NHL. The results of the study showed that women who began using hair dye before 1980 had a 30% increased risk of NHL compared to women who had never used hair dye. There was no such risk seen in women who began using the hair dye after 1980. An increased risk of follicular lymphoma (a subtype of NHL) was, however, seen in women who started using the dyes even after 1980.3
Although the results show that current hair dyes might not be intensely carcinogenic, the other side of the story could be insufficient time of usage or exposure to the modern dyes after the regulatory changes were made.
Risk Of Leukemia
Similar to NHL, cases of increased risk of leukemia were prominent in people who started using dyes before 1980 with a significant reduction in the risk in recent times. However, in this case, the risk was due to both permanent and semi-permanent dyes. The risk was also more evident in the people who had used the dyes for more than 15 years.4
The research is still in progress about the possible implications of the long-term usage of dyes and their carcinogenicity. In a nutshell, anything synthetic, involving direct contact with the skin could have potent negative impacts in a long run, as they impact the biochemistry of the body. The usage of the same is one’s personal choice or rather one’s personal risk!
|↑1, ↑2||Bolt, Hermann M., and Klaus Golka. “The debate on carcinogenicity of permanent hair dyes: new insights.” Critical reviews in toxicology 37, no. 6 (2007): 521-536.|
|↑3||Zhang, Yawei, Silvia De Sanjose, Paige M. Bracci, Lindsay M. Morton, Rong Wang, Paul Brennan, Patricia Hartge et al. “Personal use of hair dye and the risk of certain subtypes of non-Hodgkin lymphoma.” American journal of epidemiology 167, no. 11 (2008): 1321-1331.|
|↑4||Miligi, Lucia, Adele Seniori Costantini, Alessandra Benvenuti, Angela Veraldi, Rosario Tumino, Valerio Ramazzotti, Carla Vindigni et al. “Personal use of hair dyes and hematolymphopoietic malignancies.” Archives of environmental & occupational health 60, no. 5 (2005): 249-256.|