[2025 Study] Uterine Cancer Hair Straighteners Study: What We Know

Use of Straighteners and Other Hair Products and Incident Uterine Cancer

A recent study published in the Journal of the National Cancer Institute (JNCI) entitled “Use of Straighteners and Other Hair Products and Incident Uterine Cancer” sought to investigate an association between the use of chemical hair straighteners, relaxers, hair dyes, and other chemical hair products and incident uterine cancer.

This research is connected to the Sister Study, a national study administered by the National Institute of Environmental Health Sciences (NIEHS), one of the National Institutes of Health.

From 2003 to 2009, over 50,000 women aged 35 to 74 across the country joined this ongoing study.

These selected participants had a sister diagnosed with breast cancer; however, the participants were not diagnosed with it.

Because of their shared genes, environment, and experiences, studying sisters provides a greater chance to identify risk factors for breast cancer and other health conditions.

The “Use of Straighteners and Other Hair Products and Incident Uterine Cancer” study analyzed data from 33,947 women participating in the Sister Study who had a uterus at the time of registration.

The participants were also from diverse racial and ethnic groups, including:

• Black or African American: 7.4%
• Hispanic or Latina non-Black: 4.4%
• Non-Hispanic White: 85.6%
• Other races: 2.5%

These women reported their use of chemical hair products, such as hair straighteners, permanent hair dye, relaxers, and other hair products, in the last 12 months.

The results are beneficial for understanding cancer risk factors in a broad population.

For an average of 10.9 years, the researchers contacted the participants to check in on their health every year, finding out if they had a new uterine cancer diagnosis or other health changes.

If the participant died, they reached out to the next of kin.

The participants underwent more comprehensive follow-up assessments every two to three years.

The participants’ response rates were impressive, with nearly 90% completing their follow-up surveys.

Use of Straighteners and Other Hair Products and Incident Uterine Cancer: Findings and Context

Uterine cancer cases have risen over the years at an alarming rate.

These hormone-related cancers affect the female reproductive system and may be fatal.

The two types of uterine cancer are:

• Endometrial cancer: This more common uterine cancer occurs in the lining of the uterus and can often be treated successfully.
• Uterine sarcoma: This rare uterine cancer occurs in the muscle layers of the uterus and needs a more aggressive treatment approach.

High amounts of estrogen or an imbalance of estrogen and progesterone levels are critical risk factors and can fuel the growth of these cancer cells.

Endocrine-disrupting chemicals (EDCs) are synthetic estrogenic compounds that disrupt the hormonal balance in the body by altering the production, transport, and elimination of hormones.

This means that EDCs can increase the risk of uterine cancer and other hormone-sensitive cancers.

Various hair products contain EDCs and other chemicals, including:

• Formaldehyde and derivatives
• Para-phenylenediamine (PPD)
• 4-Aminobiphenyl
• Parabens
• Phthalates
• Bisphenol A (BPA)
• Cyclosiloxanes
• Diethanolamine
• Heavy metals

The presence of these specific chemicals may indicate women who use hair straightening products may have a higher risk of uterine cancer.

The researchers in the National Cancer Institute study considered several factors in this study, such as:

• Race and ethnicity
• Educational attainment
• Body mass index (BMI)
• Physical activity
• Menopausal status at enrollment
• Alcohol consumption
• Smoking habits
• Duration of oral contraceptive use
• Hormone replacement therapy
• Age at menarche or the first period

Through several sensitivity analyses, NCI researchers also made the following modifications to their data set:

• They focused on medically confirmed uterine cancer cases.
• They removed physical activity since it can confound or mediate the relationship between hair product use and uterine cancer. Hairstyling practices can also affect women’s physical activities, and those engaging in intense activities may change their hairstyling behaviors.
• They excluded women working in hair salons, barber shops, and other related businesses to remove any potential bias due to occupational exposure.
• They made adjustments for the frequent use of personal hair products.
• They excluded the first year of monitoring to assess if reverse causation is probable.
• They combined hair straighteners and permanents as Black and African American communities interchangeably use these to modify their hair texture.

After following the participants for an average of 10.9 years, the NCI cancer research team found several critical findings in their study:

• Those with uterine cancers were more likely to be older and have a higher BMI, an earlier age at menarche, and lower physical activity levels.
• Frequent users of hair straightening products belong to the Black or African American population. They also tend to be younger and have a higher BMI and lower physical activity.
• Frequent users or those who use hair straighteners four times or more in a year are twice as likely to develop uterine cancer compared to those who did not or only used these products rarely.
• The frequencies of using various hair products are weakly associated with each other.
• Those who used hair straightening products in the last 12 months have an 80% increased risk of uterine cancer.
• Seldom users or those who use hair straighteners four times or less per year have a raised but not significantly higher rate of developing uterine cancer.
• 1.64% of women who did not use hair straighteners in the past year are likely to develop uterine cancer at age 70.
• One in 85 seldom users or every 42 frequent users is likely to develop uterine cancer.
• The use of other hair products, like permanent hair dye, was not found to be associated with an increased risk for uterine cancer.
• Higher rates of uterine cancer caused by hair straightening products are primarily evident in postmenopausal women.
• Women with lower physical activity levels and frequent hair straightener use were more likely to develop uterine cancer.
• Hazard ratios of hair straightener use did not differ significantly by obesity, race, or ethnicity.

Overall, higher uterine cancer incidence rates were observed in women exposed to hair straightening products in the past 12 months before the study began.

These findings suggest that chemical exposure through hair straighteners is more dangerous than other hair products.

These chemicals are mainly absorbed through the scalp and can cause scalp lesions and burns, which increases the absorption of these chemicals through the scalp.

They can also be absorbed through other parts of the skin.

When applying hair straightening products, the hair also endures heating processes, such as blow drying and flat ironing.

Because of the heat, the chemicals and other components of the product are even more likely to be absorbed into the skin or inhaled, increasing the risk of potential harm.

Interestingly, other hair products, such as hair permanents, bleach, highlights, and permanent, semi-permanent, and temporary dyes, have a weaker association with an increased risk of uterine cancer.

These findings indicate a positive association between hair straightener use and uterine cancer.

However, this study is the first of its kind, and more research is needed to better understand the long-term effects of chemical exposure on uterine cancer.

Additionally, more research should be conducted to determine health disparities in uterine cancer, the specific chemicals and ingredients in hair products that may be causing harm, and possible intervention for reducing uterine cancer incidence.

Putting the NCI Study Results Into Context

The NCI study estimates that 1.64% of participants who did not use hair straightening products may develop uterine cancer by age 70.

However, this risk rises to 4.05% for frequent users.

While this difference in risk may seem small, it is a concerning health risk that should not be taken lightly, even though uterine cancer is relatively rare compared to other types of cancer.

While the study found a link between hair product use and the risk of uterine cancer, it is not a definitive indication of causation.

Therefore, more research is needed to better understand the relationship between hair product use and uterine cancer.

That said, women should be aware of the potential risks associated with using certain hair products and make informed decisions about the types of products they are using.

They should also take steps to reduce their exposure whenever possible.

Exposure Assessment

During the study, the researchers annually followed up on the frequency of product use among participants, whether through self-application, having someone else apply the product, or going to a salon.

They focused on seven types of hair products, including the following:

• Hair straighteners
• Hair relaxers
• Permanent, semi-permanent, and temporary hair dyes
• Bleach
• Highlights
• Pressing products
• Hair permanents or body waves

The frequency of use was divided into several categories:

• Did not use
• One to two times per year
• Every three to four months
• Every five to eight weeks
• Once per month
• More than once per month

Additionally, the researchers collected data for the incidence of non-professional applications to others using permanent, semi-permanent, and temporary hair dyes.

They also recorded the color of the hair dyes, including light and dark shades.

Previous Research Has Linked Some Types of Hair Products With Breast Cancer and Ovarian Cancer

Uterine cancers are not the only severe health condition that may be associated with hair product use.

Earlier cancer research efforts have linked hair products to an increased risk of breast and ovarian cancer.

The International Journal of Cancer study examined 46,709 Sister Study participants to find an association between hair dye and hair straightener use and breast cancer risk by ethnicity.

The researchers followed the participants for an average of 8.3 years and found 2,794 breast cancer cases.

55% of the participants reported using permanent hair dye before the study began.

Permanent hair dye use increased breast cancer risk by 45% in black women and 7% in white women.

Using hair straighteners also heightened breast cancer risk as the frequency of use increased.

This study observed significantly higher breast cancer rates in women who used permanent hair dye or hair straighteners, especially in black women.

These findings suggest these hair products may be responsible for breast carcinogenesis.

Another study focusing on the connection between hair products and ovarian cancer observed 40,559 of the Sister Study participants over an average of 18 years.

The researcher found 241 cases of ovarian cancer.

Seldom use of hair straighteners, relaxers, or pressing products was not found to increase ovarian cancer risk, but frequent use of these products increased the risk.

Using permanent hair dye also increased the risk of non-serous ovarian cancer.

These results suggest that some hair products, particularly those containing chemicals and high heat exposure, may be associated with higher ovarian cancer incidence.

Uterine Cancer Rates Are Rising in the US

The Centers for Disease Control and Prevention (CDC) cites uterine cancer as the most common gynecological cancer in the county.

The National Cancer Institute reported a 0.6% rise in occurrence and a 1.7% rise in death rates related to uterine cancer from 2010 to 2019.

Unfortunately, the number of uterine cancer cases and deaths increases each year.

The recent rise in the occurrence and mortality of uterine cancer and the connection between hair products and increased risk of uterine cancer should prompt further research into the possible causes of this type of cancer.

By better understanding the risks associated with certain hair care practices and chemicals, people can take the necessary steps to reduce their exposure to these products and hopefully reduce their risk of developing uterine cancer.

Black Women Reported to Have Higher Uterine Cancer Risk

While there’s not much difference observed in the NCI study between white and black women for hair straightening or relaxer products, African American or Black women may have an increased uterine cancer risk due to their extensive and more frequent use of various hair products.

The natural texture of many Black women’s hair may require more processing with chemical treatments, hot tools, and pressing products.

These processes may increase exposure to specific chemicals that could be carcinogenic.

Additionally, Black women typically start using hair products at earlier ages, which could further increase their risk.

More attention should be given to the risks associated with hair product use for Black women.

Black Women May Be at Higher Risk Because of Frequency of Use

African American or Black women may be at higher risk for uterine cancer due to the frequency of product use.

Because of the natural texture of their hair, Black women often utilize more and longer treatments with the help of various hair chemicals and tools.

Exposure at earlier ages also makes them more vulnerable to potential health risks.

The NCI study also found that Black women may be more likely to develop Type II endometrial cancer.

This subtype of uterine cancer usually has a poor prognosis and is more likely to be aggressive and fatal.

Unfortunately, less aggressive types of the disease are also becoming more common among Black women.

Women Who Used Hair-straightening Products Frequently Were at Higher Risk for Uterine Cancer

The study observed that women who frequently used hair straightening products were at higher risk for developing uterine cancer.

This means they used hair straighteners four or more times a year.

This research suggests that people should be aware of the risks associated with using these products and make informed decisions about their use.

Weight Management and Uterine Cancer Risk Factors

In addition to being aware of the risks associated with using hair products, women should also be mindful of their weight.

Even though obesity is not directly linked to increasing uterine cancer risk, it is a significant risk factor that can increase the chances of developing the disease.

The study reported that women with higher BMIs and lower physical activity levels were more likely to develop the disease.

Women should strive for a healthy weight and an active lifestyle to reduce their risk of developing uterine cancer.

Do You Qualify for a Hair Straightener Uterine Cancer Lawsuit?

If you or a loved one used hair straightening products and subsequently developed cancer, you may be eligible to file a claim.

Contact TorHoerman Law for a free consultation, or use the virtual legal assistant on this page to see if you qualify to file a claim instantly.

Gathering Evidence For A Hair Relaxer Lawsuit

Evidence is important in any personal injury lawsuit, especially product liability cases.

In a Hair Straightener Lawsuits, evidence may include:

• Medical records
• Medical bills
• Receipts of purchase
• Lost wages as a result of medical treatment
• Witness statements
• Doctor’s notes
• Other evidence proving use of hair relaxer products and the subsequent health impacts

Assessing Damages For Hair Straightener Lawsuits

With the help of an experienced attorney, you will begin to assess damages related to your case.

Damages refer to the total losses incurred as a result of an injury or diagnosis, both economic and non-economic.

Damages in a Chemical Hair Straightener Lawsuit may include:

• Medical bills
• Lost wages or earning capability
• Lost quality of life
• Loss of consortium
• Pain and suffering
• Emotional damages
• Permanent disability
• Other damages

TorHoerman Law: Your Hair Straightener Uterine Cancer Lawyers

Uterine cancer can be a difficult diagnosis to accept and understand.

Our Hair Relaxer Lawyers are here to help you file a legal claim for compensation.

If you have been diagnosed with uterine cancer and believe it is connected to your long-term use of hair product, you may be eligible to file a Hair Relaxer Lawsuit.

Contact TorHoerman Law for a free consultation.

You can also use the chatbot on this page to find out if you qualify for the Chemical Hair Straightener Cancer Lawsuit instantly.

Our experienced attorneys are here to review your case and provide advice on the best course of action for you and your family.

We will fight for the compensation you deserve and ensure your rights are protected.

Contact us today to get started.