Hair Relaxers

How Do Hair Relaxers Cause Cancer?

Most hair relaxers contain chemicals such as formaldehyde, metals, parabens and phthalates, synthetic endocrine-disrupting chemicals (EDCs), which may contribute to uterine cancer risk because of their ability to alter hormones. These chemicals have been associated particularly with hormone-sensitive cancers such as breast and ovarian cancer.

Hair products such as relaxers that contain EDCs may provide a pathway for these chemicals to enter the body through scalp burns and cuts often caused by hair relaxers. The NIEHS warns that exposure to even small amounts “can alter the body’s sensitive systems and lead to health problems.”

Hair Relaxers & Uterine Cancer

According to the NIH, no other studies have investigated the link between hair relaxers and uterine cancer until the NIEHS research, published in the Journal of the National Cancer Institute in October 2022. The study was conducted over nearly 11 years and revealed that women who reported using hair relaxers were almost twice as likely to have been diagnosed with uterine cancer than those who didn’t.

About the study

• Investigators identified 33,947 racially and ethnically diverse women aged 35-74 who had a uterus when they enrolled.
• Each woman was asked about their use of hair products in the previous 12 months, including hair dyes, relaxers, or pressing products and permanents or body waves.
• Women who reported frequently using hair relaxers were about 2.5 times more likely to develop uterine cancer than those who did not use the products. Frequent use is defined as more than four times in the previous 12 months.

What is Uterine Cancer?

The uterus is commonly known as the womb, where the baby develops during pregnancy. Uterine cancer is one of the most common gynecologic cancers. Diagnoses and deaths due to uterine cancer have increased in the past two decades, with more than 65,950 new cases and 12,550 deaths expected in 2022.

There are two types of uterine cancer – endometrial cancer (more common) and uterine sarcoma. Uterine cancer symptoms include bleeding between periods or after menopause. The Centers for Disease Control and Prevention (CDC) says that “[m]ost uterine cancers are found in women who are going through or who have gone through menopause—the time of life when your menstrual periods stop.”

Key risk factors for uterine cancer include exposure to excess estrogen and a hormonal imbalance of estrogen and progesterone.

The researchers did not find similar links between uterine cancer and the use of other hair products, such as hair dyes, highlights, and perms.

Hair Relaxers & Other Gynecological Injuries

The NIEHS study relied on data from another research project called the Sister Study. The goal of this nationwide project by the NIH was to learn how the environment and genes may affect a woman’s risk of developing breast cancer.

Previous studies involving data from the Sister Study have linked hair dye and hair relaxers to breast cancer cases. This risk was even greater among Black women — a 45% increased risk compared to a 7% increased risk among white women. Researchers also found that more frequent use of the products was also linked to an increased risk of breast cancer in Black women but not among white women. Previous studies have also linked adult use of hair relaxers with ovarian cancer.

EDCs are also causing conditions such as endometriosis and uterine fibroids, which have been linked to infertility and preterm deliveries.

Endometriosis

When tissue like the endometrium, which lines the inside of the uterus, grows on the outside of the uterus, a condition called endometriosis occurs. Endometriosis is painful and can lead to fertility problems.

Uterine Fibroids

Uterine fibroids are noncancerous growths of the uterus that often appear during the childbearing years. They aren’t life-threatening but can be painful and can lead to infertility or pregnancy loss.

Does the FDA regulate hair relaxers?

The Food and Drug Administration (FDA) regulates cosmetics, including hair relaxers, based on the Federal Food, Drug, and Cosmetic Act and the Fair Packaging and Labeling Act for products marketed for retail. Companies and individuals manufacturing or marketing hair relaxers are responsible for the safety and labeling of products and ingredients. The law requires companies to list their products’ ingredients. However, the law allows exceptions to protect “trade secrets.” According to the National Women’s Health Network, this exception can allow harmful and toxic ingredients to remain hidden from consumers.