Hair Relaxer Uterine Cancer Link: What Studies Show

Last updated: October 2026

Research has linked frequent use of chemical hair relaxers to a higher risk of uterine cancer. A large 2022 National Institutes of Health study found that women who straightened their hair more than four times a year had more than double the risk of uterine cancer compared with women who never did. The study shows a link, not proof that relaxers cause cancer, but it is the main science behind thousands of lawsuits. The sections below also explain how to record your product history, how doctors test for hair relaxer uterine cancer concerns and what to ask at your next visit.

This article explains what the research on hair relaxer uterine cancer risk found, who may be most affected, and what symptoms to watch for.

What the NIH hair relaxer study found

The key study came from the Sister Study, a long-term NIH project that tracks the health of U.S. women. It was published in the Journal of the National Cancer Institute on October 17, 2022.

Here are the main findings from the NIH announcement:

• 33,497 women ages 35 to 74 took part.
• They were followed for almost 11 years.
• 378 of them were diagnosed with uterine cancer.
• “Frequent use” meant using straightening products more than four times in the past year.

Estimated risk by age 70

The researchers estimated each group’s chance of getting uterine cancer by age 70:

• Women who never used straighteners: 1.64%
• Frequent users: 4.05%

The lead researcher called this doubling “concerning.” She also pointed out that uterine cancer is still fairly rare. Put simply, most frequent users will not get uterine cancer, but their risk appears higher.

Why relaxers might raise cancer risk

Scientists do not yet know exactly how relaxers might raise cancer risk. The NIEHS, part of NIH, named several chemicals of concern found in some straightening products:

• Parabens
• Bisphenol A (BPA)
• Metals
• Formaldehyde

Some of these chemicals can act like hormones in the body. They are sometimes called endocrine disruptors. Uterine tissue is sensitive to hormones, which is one reason researchers are concerned.

Scalp burns may matter

Relaxers are strong chemicals. They can cause burns and sores on the scalp. The NIEHS notes that these injuries may let more chemicals soak into the body than other personal care products would.

Other cancers studied

Uterine cancer is the focus of most lawsuits, but Sister Study researchers have looked at other cancers too.

Ovarian cancer

A 2021 study in the journal Carcinogenesis followed 40,559 women. It found that frequent use of straighteners or relaxers was linked to about twice the risk of ovarian cancer. Women who had used them less often did not show a clear increase.

Breast cancer

A 2019 NIH study of 46,709 women found that using chemical straighteners every five to eight weeks was linked to about a 30% higher breast cancer risk. The authors said these results need to be confirmed by more research.

How to read these study results

Health headlines can make numbers sound scarier or safer than they are. A few points can help you make sense of the research.

“Linked to” is not the same as “causes”

These are observational studies. Researchers asked women about their habits and then tracked who got sick. This kind of study can show a pattern. It cannot prove that one thing directly caused another.

Relative risk vs. your actual risk

“Twice the risk” sounds large. But when a disease is uncommon, doubling it still leaves the actual chance fairly low. In the NIH study, the estimated risk by age 70 went from under 2 in 100 to about 4 in 100.

Frequency seems to matter

In both the uterine and ovarian cancer studies, the clearest signal showed up in women who used products often. That pattern, where more use is tied to more risk, is one thing scientists look for when judging whether a link may be real.

More research is under way

Scientists are still studying which chemicals may be involved and how. Their findings may shape both health advice and the lawsuits in the years ahead.

Who may be most affected

Anyone can use hair relaxers. But the research shows the burden does not fall evenly.

• About 60% of the women in the NIH study who used straighteners identified as Black.
• Black women tend to use relaxers more often and start at younger ages, according to the NIEHS.
• Uterine cancer rates have been rising in the U.S., especially among Black women.

Salon workers may also face more exposure because they handle these products often. Researchers have not yet measured cancer risk for stylists as closely as for customers.

Uterine cancer warning signs

Uterine cancer is often found early because it tends to cause symptoms. If you have used relaxers, knowing the signs can help you speak up sooner.

The National Cancer Institute lists these signs of endometrial cancer, the most common type of uterine cancer. Talk to a doctor if you notice:

• Vaginal bleeding after menopause, even light spotting
• Bleeding or discharge that is not part of your period
• Difficult or painful urination
• Pain during sex
• Pain in the pelvic area

These symptoms have many possible causes. Only a doctor can tell you what is going on. It may help to tell your doctor about your relaxer use as part of your health history.

From science to the courtroom

The 2022 study led to a wave of lawsuits. Federal cases were combined into one group, MDL No. 3060, in Chicago in February 2023.

As of September 1, 2026, federal court data shows 12,129 hair relaxer cases pending. The lawsuits claim some manufacturers did not warn customers about possible cancer risks. The companies deny that their products cause cancer. No settlement has been announced, and the first test trial is set for 2027.

In a lawsuit, the science is only one piece. Each person also needs to show their own product use and diagnosis. That is why records matter.

Helpful records to gather

• Pathology or medical reports showing a uterine or ovarian cancer diagnosis
• The brands you used and about how often, over how many years
• Salon receipts, photos or product containers if you still have them

Filing deadlines vary by state and claim type. Some deadlines start when you learned about a possible link to a product.

How to Build Your Hair Relaxer Use History

Many women used relaxers for decades, starting as children. Remembering every brand and date is hard. But a rough history can help your doctor understand your health background. It is also one of the first things a law firm asks about when reviewing hair relaxer uterine cancer questions.

Start with the big picture

Begin with simple questions. Writing short answers is enough.

• How old were you when you first had a relaxer?
• About how often did you get touch-ups, such as every six weeks or every few months?
• Did you mostly relax your hair at home, at a salon or both?
• During what years did you use relaxers most often?
• When did you stop, if you have stopped?

Brands and products

Try to list any brands you remember, even if you are not sure. Old photos, family members or a long-time stylist may help jog your memory. If you still have boxes, jars or receipts, keep them in a safe, dry place.

Scalp burns and sores

The article explains that scalp burns may let more chemicals into the body. If you remember burns, scabs or sores after a relaxer, note when they happened and whether you sought treatment. Any doctor or salon records of these injuries may also be useful.

Salon workers

If you worked as a stylist, note the years you worked, how many relaxers you applied in a typical week and whether you wore gloves. Researchers have not measured cancer risk for stylists as closely as for customers, but your work history is still part of your health story.

Why your history matters in hair relaxer uterine cancer cases

The NIH research found the clearest signal among women who used straighteners often. That is why frequency and years of use come up so much. In hair relaxer uterine cancer cases, a law firm will usually want to know how often you used relaxers and over what time period, not just whether you ever used them.

Your history does not have to be perfect. Reasonable estimates, such as “every six to eight weeks from about age 12 to 35,” are common and useful.

Keep the history in one place

Put your notes on a single page or in one folder. Update it when you remember something new. A clear history can help you answer questions about hair relaxer uterine cancer concerns without having to start from memory each time.

How Doctors Check for Uterine Cancer

If you have symptoms such as bleeding after menopause, your doctor may order tests. Knowing what to expect may make these visits a little less stressful. The tests below are described by the National Cancer Institute for endometrial cancer, the most common type of uterine cancer.

Physical exam and health history

Your doctor will ask about your symptoms, your past health and your family history. This is a good time to mention your relaxer use. Doctors may not ask about hair products unless you bring them up.

Transvaginal ultrasound

This imaging test uses sound waves to look at the uterus and nearby organs. A small probe is placed in the vagina. It can show the thickness of the uterine lining and other changes.

Endometrial biopsy

In this test, a thin, flexible tube is passed through the cervix to remove a small sample of tissue from the lining of the uterus. A lab then checks the sample for cancer cells.

Hysteroscopy and D&C

A hysteroscopy uses a thin, lighted tube to look inside the uterus. A dilatation and curettage, often called a D&C, removes tissue samples from the inner lining. These may be done if a biopsy is unclear or more tissue is needed.

Waiting for results

Waiting for biopsy results can be one of the hardest parts. Ask your doctor when results are expected and how you will be contacted. If you are worried about hair relaxer uterine cancer risk, share that worry so your care team can answer your questions directly.

Imaging after a diagnosis

If cancer is found, doctors may order a chest x-ray, CT scan, MRI or PET scan to see whether it has spread. These results help set the stage of the cancer.

Questions to Ask Your Doctor About Hair Relaxer Uterine Cancer Concerns

Short appointments can make it hard to remember everything. Bringing a written list of questions can help you get clear answers about hair relaxer uterine cancer worries and about your own care.

If you have symptoms but no diagnosis

• What could be causing my symptoms?
• Which tests do you recommend, and when will I get results?
• Should my past relaxer use change how closely I am checked?
• What symptoms should make me call right away?

If you have been diagnosed

• What type and stage of uterine cancer do I have?
• What treatment options do you recommend, and why?
• How might treatment affect my ability to have children, if that matters to me?
• What side effects should I expect, and how can they be managed?
• Can I get copies of my pathology and surgery reports?

If you are still using relaxers

• Is there anything you suggest I change about my hair care routine?
• Are there signs I should watch for given my history?

Your doctor may not have firm answers about relaxers, since research is still growing. That is okay. The goal is to make sure your history is part of your medical record and that you get the right tests and care.

Bring support if you can

A friend or family member can take notes, ask follow-up questions and help you remember what was said. You can also ask whether the office offers a patient navigator, who helps people move through cancer care.

Terms You May See in Your Medical Records

Cancer records are full of medical words. Knowing a few of them can help you read your own reports. It can also make it easier to talk with a law firm about hair relaxer uterine cancer claims, since firms often review these same documents.

Endometrium and endometrial cancer

The endometrium is the inner lining of the uterus. Endometrial cancer starts in this lining and is the most common type of uterine cancer.

Uterine sarcoma

A rarer type of uterine cancer that starts in the muscle or other tissues of the uterus, rather than the lining.

Pathology report

A report from the lab that studied your tissue. It confirms whether cancer is present and describes the type of cells.

Stage

A number that describes how far cancer has spread. The NCI explains that in stage I, cancer is found in the uterus only. In stage IV, it has spread beyond the pelvis.

Hysterectomy

Surgery to remove the uterus. The NCI lists surgery as the most common treatment for endometrial cancer. A bilateral salpingo-oophorectomy, sometimes written as BSO, also removes both ovaries and fallopian tubes.

Adjuvant therapy

Treatment given after surgery, such as radiation, chemotherapy or hormone therapy, to lower the chance that cancer returns.

Talking with family about hair relaxer uterine cancer risk

Relaxer use often runs in families, passed down from mothers and grandmothers to daughters. If you have been diagnosed, you may want to tell female relatives so they can talk with their own doctors about symptoms.

Keep the conversation calm and factual. You can explain that research shows a link between frequent use and higher risk, but that most frequent users will not get uterine cancer. Encourage them to see a doctor for any bleeding after menopause or other warning signs. Sharing what you have learned about hair relaxer uterine cancer can help loved ones make their own informed choices.

Why these records matter

In the lawsuits, each person needs to show their own diagnosis. Pathology and surgery reports are often the clearest proof. Keep copies of these records with your product use history. If you are thinking about hair relaxer uterine cancer claims, a participating law firm may review these papers and explain whether you may qualify. Filing deadlines vary by state and claim type, so it can help to ask sooner rather than later.

Hair relaxer uterine cancer: frequently asked questions

How Direct2Attorney can help

If you used relaxers and were diagnosed with uterine or ovarian cancer, you may qualify to file a claim. Direct2Attorney connects people with participating law firms. Share your story on our hair relaxer lawsuit page, and a firm may review your options.

The research on hair relaxer uterine cancer risk is still growing. You deserve clear answers about your health and your rights.

Direct2Attorney is a legal marketing and referral service, not a law firm. This article is general information, not legal advice. Submitting information does not create an attorney-client relationship.