First Published: October 19, 2022
Republished: September 16, 2023
Hair Relaxers and Straighteners Linked to Increase Risk of Cancer in Women
Research shows that there is a connection between the use of hair-straightening chemicals such as relaxers, perms, dyes, straighteners, or pressing products, and increased risk of cancer in women.
According to the new study, hair products contain hazardous chemicals with endocrine-disrupting and carcinogenic properties; hence, the use of such chemicals to treat hair causes hormone-related cancers such as breast cancer, ovarian cancer, and cancer of the uterus (uterine cancer).
The researchers added that black women are at the highest risk of having cancer associated with the use of hair relaxers and other hair treatment chemicals.
The large size of participants comprised people from different races, backgrounds, and geographical locations. 7.4% Black/African American, 85.6% non-Hispanic white, 4.4% Hispanic/Latina, and 2.5% people from other races and ethnicity.
Some of the participants made use of hair products in the prior 12 months, including hair dyes; straighteners, relaxers, or pressing products; and permanents or body waves. After 10.9 years of follow-up, 378 uterine cancer cases were identified.
To confirm the relationship between the chemicals and the cancers, some of the participants were told to withdraw from using the products for 12 months, while others continued using the products.
At the end of the 12 months, 1.64 % of women who did not use hair straighteners for the past year were predicted to develop uterine cancer at age 70. The result was higher for women who ever used chemicals on their hair at 1.18% but highest at 4% of the women who used the hair straighteners repeatedly.
The research also observed that women with low physical activity like exercise were at higher risk. This is because physical activity has been associated with decreased sex steroid hormones and less chronic inflammation. Hence women with higher physical activity might be less susceptible to other risk factors for uterine cancer.
About the influence of race or ethnicity on hair straighteners associated with cancer, the researchers added that the cause of the increase in cancer from the products among black women was associated with the chemical formula used to produce such products and the fact that black women used more hair-straightening chemicals, relaxers, and others more than women of other races and ethnicity.
“Although no differences in the hazard ratios between racial and ethnic groups were observed, the adverse health effects associated with straightener use could be more consequential for African American and/or Black women because of the higher prevalence and frequency of hair product use, younger age of initiating use, and harsher chemical formulations”.
The researchers said that although previous research linked some hair products to other forms of cancers, products like perms, body waves and dyes did not show signs of association with uterine cancer but there was a strong association between hair straighteners and uterine cancer.
“Higher percutaneous absorption of chemicals has been observed in the scalp compared with other skin such as on the forearm, palm, and abdomen. Straightener use may cause scalp lesions and burns, which facilitates the permeability of chemicals through the scalp”.
It also added that the use of hair dryers (flat ironing or blow drying) and other heat devices during straightening hair treatment could release thermally decompose chemicals from the chemical products, leading to potential higher exposures to hazardous chemicals among the users.
“The challenge is that the impact of these chemicals might not be limited to hormonal processes, but they could also impact other systems, including our immune and vascular systems. Understanding how these chemicals work beyond the hormonal system is still a new and growing area of research,” Todd said.
“Hair product constituents, including formaldehyde and formaldehyde-releasing chemicals in some straighteners, and oxidized para-phenylenediamine and 4-aminobiphenyl in hair dyes, have also played a potential role in carcinogenesis, supporting an association between hair product use and cancer development”.
The research concluded that these findings are the first epidemiologic evidence of an association between the use of straightening products and uterine cancer. Therefore, more research is needed to confirm this finding and properly find out which chemicals in the products are responsible for the increased cancer risk on usage.
According to the new study, hair products contain hazardous chemicals with endocrine-disrupting and carcinogenic properties; hence, the use of such chemicals to treat hair causes hormone-related cancers such as breast cancer, ovarian cancer, and cancer of the uterus (uterine cancer).
The researchers added that black women are at the highest risk of having cancer associated with the use of hair relaxers and other hair treatment chemicals.
About the Cancer Research and the Study Outcome
The research titled “Use of Straighteners and Other Hair Products and Incident Uterine Cancer” was published on Monday by a group of researchers from the National Institute of Health in the Journal of the National Cancer Institute. The study was carried out on 33 947 Sister Study participants, aged 35-74 years, who had uterus enrollment between 2003-2009 and provided regular feedback through a questionnaire.The large size of participants comprised people from different races, backgrounds, and geographical locations. 7.4% Black/African American, 85.6% non-Hispanic white, 4.4% Hispanic/Latina, and 2.5% people from other races and ethnicity.
Some of the participants made use of hair products in the prior 12 months, including hair dyes; straighteners, relaxers, or pressing products; and permanents or body waves. After 10.9 years of follow-up, 378 uterine cancer cases were identified.
To confirm the relationship between the chemicals and the cancers, some of the participants were told to withdraw from using the products for 12 months, while others continued using the products.
At the end of the 12 months, 1.64 % of women who did not use hair straighteners for the past year were predicted to develop uterine cancer at age 70. The result was higher for women who ever used chemicals on their hair at 1.18% but highest at 4% of the women who used the hair straighteners repeatedly.
Who is at Highest Risk of Hair-straightening Chemicals Related Cancers?
As stated earlier, the rate of cancer risk from the use of hair-straightening chemicals was higher among those who frequently used the chemicals.The research also observed that women with low physical activity like exercise were at higher risk. This is because physical activity has been associated with decreased sex steroid hormones and less chronic inflammation. Hence women with higher physical activity might be less susceptible to other risk factors for uterine cancer.
About the influence of race or ethnicity on hair straighteners associated with cancer, the researchers added that the cause of the increase in cancer from the products among black women was associated with the chemical formula used to produce such products and the fact that black women used more hair-straightening chemicals, relaxers, and others more than women of other races and ethnicity.
“Although no differences in the hazard ratios between racial and ethnic groups were observed, the adverse health effects associated with straightener use could be more consequential for African American and/or Black women because of the higher prevalence and frequency of hair product use, younger age of initiating use, and harsher chemical formulations”.
The researchers said that although previous research linked some hair products to other forms of cancers, products like perms, body waves and dyes did not show signs of association with uterine cancer but there was a strong association between hair straighteners and uterine cancer.
How Hair-Straighteners Access and Cause Cancer in the Body
According to the research, the body absorbs chemicals faster when there are scalps, injuries, or lesions. Most skin products cause burns which give them access to the blood and eventual access to different parts of the body.“Higher percutaneous absorption of chemicals has been observed in the scalp compared with other skin such as on the forearm, palm, and abdomen. Straightener use may cause scalp lesions and burns, which facilitates the permeability of chemicals through the scalp”.
It also added that the use of hair dryers (flat ironing or blow drying) and other heat devices during straightening hair treatment could release thermally decompose chemicals from the chemical products, leading to potential higher exposures to hazardous chemicals among the users.
More Shocking statement by the Researchers on Cancer Related to Hair Products
In an interview, one of the researchers, Tamara James-Todd who is an epidemiologist at Harvard T.H. Chan School of Public Health told CNN that the use of those chemicals may have more serious impacts on other body systems besides hormonal disruptions.“The challenge is that the impact of these chemicals might not be limited to hormonal processes, but they could also impact other systems, including our immune and vascular systems. Understanding how these chemicals work beyond the hormonal system is still a new and growing area of research,” Todd said.
Conclusion from the Hair-straightening Chemicals Related Cancer Research
In summary of the research, “Hair product use, a predominant exposure pathway to various EDCs, has been associated with hormone-sensitive cancers including breast and ovarian cancer in previous epidemiologic studies,” the authors said.“Hair product constituents, including formaldehyde and formaldehyde-releasing chemicals in some straighteners, and oxidized para-phenylenediamine and 4-aminobiphenyl in hair dyes, have also played a potential role in carcinogenesis, supporting an association between hair product use and cancer development”.
The research concluded that these findings are the first epidemiologic evidence of an association between the use of straightening products and uterine cancer. Therefore, more research is needed to confirm this finding and properly find out which chemicals in the products are responsible for the increased cancer risk on usage.
