Chemical Hair Relaxers & Their Growing Health Concerns

Chemical hair relaxers — sometimes called hair straighteners — break the protein bonds in curly or coiled hair to make it straight. However, scientific evidence links long-term hair relaxer use to women’s health issues such as scalp reactions, kidney injury, breast cancer and uterine cancer.

Businessman Garrett Morgan invented one of the first hair straighteners designed for Black hair in the early 1900s. Since then, companies such as Dark & Lovely, L’Oreal, Soft & Beautiful and others have continued to manufacture hair straighteners.

Companies often heavily marketed these products to Black women. More than 70% of Black women use hair straighteners, according to a study published in Environmental Health Perspectives.

Some chemical hair relaxer lawsuits claim that manufacturers targeted women of color and failed to issue warnings about the health risks of these products.

Chemical permanent hair straighteners contain a variety of toxic chemicals linked to topical side effects (scalp irritation, burns) and those that affect the whole body (cancer, reproductive problems). These chemicals include calcium hydroxide, parabens, phthalates, formaldehyde, glycolic acid derivatives, guanidine and sodium hydroxide.

Chemical hair straightener lawsuits claim that manufacturers had access to studies linking phthalates and other EDCs in hair relaxers to various reproductive cancers for decades, but failed to warn the public.

Plaintiffs argue that EDCs in hair relaxers “caused or increased the risk of developing uterine, ovarian or breast cancer, endometriosis, uterine fibroids or other injuries to the reproductive system.”

Cancer Risks Linked to Permanent Hair Straighteners

In recent years, researchers have published studies on cancer risks related to chemical hair straighteners and relaxers. Using these products more than four times a year has been linked to an increased risk of developing uterine, breast and ovarian cancer.

Studies also highlight that hair straightener use is more common among Black women, leading to the potential for a greater risk of uterine cancer than other ethnicities.

Reproductive & Endocrine Disruptions from Hair Straightening Products 

EDCs in hair relaxers — such as phthalates and parabens — can cause hormone imbalances. These imbalances can lead to reproductive disorders, cancer and other immune-related diseases.

“It is hypothesized that some of the chemicals found in these products (such as phthalates, parabens and cyclosiloxanes) can essentially behave like hormones in the body [such as estrogen]. Elevated estrogen seems to increase the likelihood of development of uterine cancers,” oncologist Daniel Landau told Drugwatch.

Young girls are particularly vulnerable to EDCs because these chemicals may affect physical development during childhood and adolescence. The EDCs in permanent hair straighteners may even affect their reproductive health by altering the ovarian structure.

A 2023 study in the American Journal of Epidemiology also found that women who used hair relaxers at a young age experienced decreased fertility. Women who used these products for 10 years or more, five or more times a year, had the most significant decreases in fertility.

Exposure to chemicals — such as EDCs — in hair straighteners can occur through inhalation, absorption through the skin or ingestion.

Since users apply hair relaxers on the scalp, skin absorption is the most common way these chemicals can get into the body. The scalp absorbs chemicals more easily than other areas of the skin. Some chemicals may cause scalp burns, which increase the openings in the skin that more readily absorb the chemicals.

“Chemical hair straighteners work by disrupting disulfide bonds found in keratin, the protein that makes up the strands of our hair. The chemicals responsible for that disruption are suspected to increase the risk for several types of cancer, particularly uterine cancer,” pharmacist and toxicologist Shannon L. Fitzgerald told Drugwatch.

Who Faces the Greatest Health Risks from Hair Straighteners?

People with the most significant risks from hair relaxers include Black women, pregnant women and their unborn babies, hair salon workers and people who use these products more than four times a year.

In the case of hair relaxers, the health risks increase with frequent and long-term exposure. Many Black women who used hair relaxers started at a young age — in some cases, as early as four years old.

“The diagnosis of Black women with uterine cancer, more specifically endometrial cancer, is higher than women of any other race or ethnicity. The use of hair straightener chemicals could contribute to the higher incidence,” said Dr. Jerome Burke, a medical toxicologist.

Manufacturer negligence is at the heart of many hair straightener lawsuits. Plaintiffs claim hair relaxer manufacturers engaged in “negligent, willful and wrongful conduct in connection with the design, development, manufacture, testing, packaging, promoting, marketing, distribution, labeling and/or sale” of these products.

Because of this alleged negligence, thousands of women have sued these companies. As of March 2025, there are more than 9,700 pending lawsuits in federal court in the Northern District of Illinois.

Issues such as the lack of strong FDA regulations for cosmetics and industry lobbying for reduced chemical regulations put consumers at increased risk.

What Did Hair Product Manufacturers Know About These Risks?

According to hair relaxer lawsuits, manufacturers should have known about the health risks for decades because of available studies linking the chemicals in these products to various health problems. Since the litigation is ongoing, internal documentation and other evidence of what companies knew about risks isn’t yet public.

However, hair relaxer companies have claimed that their products are safe and hair straightener lawsuit injury claims are without merit. In a 2023 statement, L’Oreal said its products — and those of its subsidiary, SoftSheen-Carson — are subject to rigorous scientific evaluation.

“While we understand the desire of each plaintiff to find answers to and relief from their personal health concerns, we are confident in the safety of SoftSheen-Carson’s products and believe the allegations made in these lawsuits have neither legal nor scientific merit,” the company said in a statement.

How the Beauty Industry Avoids Health Warnings

The FDA relies on safety data from hair relaxer companies but doesn’t require specific tests to prove the products are safe, leading to fewer FDA warnings about potentially dangerous chemicals. Under these laws, the beauty industry is essentially responsible for regulating itself.

U.S. law says cosmetic products — including hair relaxers — cannot contain harmful ingredients, but manufacturers don’t have to submit safety data to the FDA. In addition, ingredients in hair relaxers don’t need FDA approval before they reach the market.

This leads to fewer regulations that protect consumers. The FDA only restricts or prohibits nine cosmetic ingredients for safety reasons, but The European Union regulates more than 1,300.

Manufacturers must list chemicals deemed dangerous on warning labels. However, some companies may use deceptive labeling to hide dangerous ingredients such as formaldehyde, a known toxic chemical. For example, some makers of hair straighteners will say that their product is formaldehyde-free even if it contains methylene glycol, which the American Chemistry Council says is “formaldehyde in solution.”

How Lawsuits Exposed the Dangers of Hair Straighteners

Shortly after the release of the 2022 study linking chemical hair relaxers to uterine cancer, Jenny Mitchell filed the first uterine cancer hair relaxer lawsuit. She had used hair relaxers since she was eight years old.

Her complaint against L’Oreal (and its subsidiary, SoftSheen-Carson), Strength of Nature, Dabur International and Namaste Laboratories claims prolonged exposure to phthalates and other EDCs in the companies’ products led her to develop uterine cancer. The lawsuit details how chemicals in hair straighteners cause cancer and how product manufacturers reinforced Eurocentric beauty standards and targeted Black women, starting when they were young girls.

CNN wrote a story about Mitchell’s lawsuit, which she announced at a news conference. More stories followed, thrusting the dangers of hair relaxers into the public eye. Close to 10,000 lawsuits followed, claiming hair relaxer use led to cancer.

So far, the FDA has not issued official safety communications regarding hair relaxers’ connection to cancer and other hormone-related health issues. In fact, an FDA spokeswoman told the New York Times, “At the present time, the FDA does not have evidence that phthalates as used in cosmetics pose a safety risk.”

However, the agency has released some information warning consumers that formaldehyde in hair straighteners is a known human carcinogen that could cause other health problems, such as irritation of the eyes, nose, lungs and skin.

“We’re glad that the FDA finally decided to ban these products, which the agency started planning to do in 2016. The research evidence has been clear for more than a decade,” Dr. Diana Zuckerman, president of the National Center for Health Research, told Drugwatch. “But we have to wonder how many women have been harmed in the meantime, and why did it take the agency so long to finally do the right thing to protect consumers?”

The FDA originally scheduled a ban on formaldehyde in hair relaxers to take effect in April 2024. However, the FDA pushed back the ban to July 2024 and then to September 2024. As of March 2025, there has been no update on if the ban will go through.

If you have used chemical hair straighteners and haven’t suffered any side effects, you don’t need to take action. However, you may want to monitor your health and consider other options for hair straightening to prevent any future injuries. Hair relaxer side effects such as cancer may not be apparent right away.

If you continue using hair relaxers, the FDA advises that you should use them according to package directions to prevent skin, hair and eye injuries.

How to Tell if Hair Straighteners Have Affected Your Health

For many people, scalp burns and skin irritation are the most apparent chemical hair straightener injuries. However, the symptoms of endocrine disruption from EDCs have links to altered hormone levels and may be missed or mistaken for other disorders.

If you suffer from any of the above symptoms, discuss them with your doctor and seek proper treatment.

What Are the Best Non-Toxic Hair Straightening Options?

Some of the best non-toxic hair straightening methods include oils, commercial products and non-chemical methods like extensions.

Keep in mind that because these are chemical-free, they won’t work the same as traditional chemical hair relaxers. These suggestions are meant for more natural hairstyles.