The Association Between Cancer Development in Black Women and Hair Relaxer Usage

What hair product can be commonly found in the possession of black women across the world? A classic hair relaxer. From children to young adults, and even to the elderly, hair relaxers are a popular staple in the black community. They are creams which are used to chemically straighten naturally kinky or curly hair, without having to struggle with a flat iron. Despite their convenience, hair relaxers aren’t exactly easy to use. They burn the scalp when used properly and incorrectly, and if they are left on for too long, they can easily cause scarring. The potential for burns and scars hasn’t deterred many from using relaxers though. What should be deterring the black community from using hair relaxers is the increased risk of cancer associated with hair relaxers. Black women who use relaxers frequently—more than 7 times a year—are at an increased risk for developing breast cancer.

The active ingredient in most relaxers is sodium hydroxide, which is labeled as ‘lye’ when listed as an ingredient. Lye-based hair relaxers have a high pH, usually 13 or higher, and as relaxers are applied, they raise the pH of natural hair. Relaxers break down the bonds of natural hair and chemically straighten kinks. While lye just seems like a chemical in a hair product, it is so much more harmful than it seems. Relaxers containing lye have endocrine-disrupting compounds.

Cancer occurs when mitosis happens too frequently. Mitosis occurs too frequently when a mutation occurs in a cell. Mutations occur to cells for various reasons, and exposure to certain ingredients increases the risk for certain genetic mutations, and cancer as a whole. Certain chemicals that are found in relaxers, including lye, have been classified as hormone disruptors. “Hormone disruptors can affect how estrogen and other hormones act in the body — by blocking them or mimicking them — which throws off the body’s hormonal balance…extra estrogen can cause hormone-receptor-positive breast cancer to develop and grow.” (DePolo). While this information may make it seem clear that relaxers cause cancer, the research done on this subject doesn’t claim this straightforward. More research still needs to be done on the current findings of multiple studies to establish a link between relaxer usage and cancer development, but current studies are important, as they reveal the risks that come with using highly processed hair products.

In the Black Women’s Health Study, 50,543 women were studied. 70% of the women used relaxers moderately, 20% used relaxers heavily, 5% used relaxers lightly, and 5% never used relaxers. 33% of the moderate and heavy relaxer users used relaxers seven or more times a year. 16% of all the women used relaxers containing oye, 13% of the women didn’t know if their relaxers contained lye or not, and 71% of women used relaxers that didn’t contain lye. 2,311 women in the study had been diagnosed with breast cancer between 1997 and 2017. Of these women, 1,420 were estrogen-receptor positive, 601 were estrogen-receptor positive, and 286 were triple negative (which is typically the most aggressive form of breast cancer). “Overall, the researchers found no association between an increase in breast cancer risk and using hair relaxers. Still, the results suggested that heavy users of hair relaxers containing lye may have an increased risk of estrogen-receptor-positive breast cancer.” (DePolo). Kimberly Bertrand, ScD, assistant professor of medicine at Boston University School of Medicine, said in a statement, “Those who used these products at least seven times a year for 15 or more years, which represented approximately 20% of women in our study — had about a 30% increased risk of estrogen-receptor-positive breast cancer.”

In the Sister Study, 33,000 women participated in a case study, in which they were asked about the different hair products that they used. Relaxers quickly became the focus of this study because, after 11 years of follow-ups, it was reported that “women who reported frequent use of hair straightening products, defined as more than four times in the previous year, were more than twice as likely to go on to develop uterine cancer compared to those who did not use the products” (Hair Straightening Chemicals Associated with Higher Uterine Cancer Risk). It is important to note that this doesn’t mean that using relaxers causes uterine cancer, rather, it increases the risk for the development of it. The study goes on to estimate that “1.64% of women who never used hair straighteners would go on to develop uterine cancer by the age of 70; but for frequent users, that risk goes up to 4.05%,” said Alexandra White, Ph.D., head of the NIEHS Environment and Cancer Epidemiology group and lead author on the new study. ‘This doubling rate is concerning. However, it is important to put this information into context - uterine cancer is a relatively rare type of cancer” (Hair Straightening Chemicals Associated with Higher Uterine Cancer Risk). Even though uterine cancer is rare, it is “the most common cancer of the female reproductive system, with 65,950 estimated new cases in 2022. Studies show that incidence rates of uterine cancer have been rising in the United States, particularly among Black women” (Hair Straightening Chemicals Associated with Higher Uterine Cancer Risk).

Finally, in a 2018 study done in Ghana, “every use of hair relaxers was associated with a 58% increased risk of breast cancer overall (OR = 1.58, 95% CI: 1.15–2.18), and the association was stronger for use of non-lye products than for lye products (18). Ever use of hair straighteners was associated with a 58% increase in breast cancer risk” (Brinton).

The findings of the many studies done on the risks associated with relaxer usage and cancer in black women are, in a way, inconsistent. It is unclear if lye-based relaxers increase the risk of developing cancer in women more than relaxers without lye, and it is unclear altogether if relaxer usage certainly significantly increases the risks of developing cancer. However, from the research that does exist, an association between heavy relaxed usage and the development of cancer has been established. More research ultimately needs to be done on the subject, but it is clear that staying away from relaxers altogether is a healthy decision, especially for African American women, as they are the target audience for hair relaxers. It has been reported that “Black women are 41% more likely to die from breast cancer than white women, despite a lower incidence of the disease” (Cancer Facts & Figures for African American/Black People), so black women must be extremely cautious in the products that they routinely use that have associated cancer risks.

---

Rebecca Fekru is a 17-year-old Ethiopian-American from Ohio. In her free time, she enjoys listening to music (mostly The Weeknd), going on walks, playing Mario Kart, and journaling. In the future, she hopes to pursue a career in global public health.

References:

• Brinton, Louise A, et al. “Skin Lighteners and Hair Relaxers as Risk Factors for Breast Cancer: Results from the Ghana Breast Health Study.”

• “Cancer Facts & Figures for African American/Black People.” American Cancer Society

• DePolo, Jamie. “Untangling Link between Hair Relaxers and Breast Cancer Risk in Black Women.”

• "Hair Relaxers: Ph Level of Hair during Processing.”

• “Hair Straightening Chemicals Associated with Higher Uterine Cancer Risk.”

• "Sodium Hydroxide.” Centers for Disease Control and Prevention