What Chemicals Are in Hair Relaxers?

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Most women go above and beyond to maintain their hair in the best possible condition. Unfortunately, some of the hair products women have been using to straighten their hair are a suspected source of uterine cancer.

Research published in the Journal of the National Cancer Institute on October 17, 2022, suggests an increased risk of uterine cancer in women using hair straightening products regularly.

In this post, we examine the link between hair relaxers and cancer, the women at the highest risk of developing uterine cancer from chemicals in hair products, and what to do if diagnosed with uterine cancer.

Chemicals Present in Hair Relaxers

Many hair relaxer products on the market today fall under the categories of hydroxide relaxers or thioglycolate relaxers.

NaOH, known as sodium hydroxide (lye), is a common hydroxide relaxer used by professionals for its potency. Potassium hydroxide and lithium hydroxide are sometimes used for less-sensitive scalps.

Ammonium thioglycolate is an example of a thio relaxer with a less alkalic pH than hydroxide relaxers. Still, hydroxide and thio relaxers can cause permanent hair damage if used incorrectly together.

Today, the ingredients under the most scrutiny for potentially increasing the risk of uterine cancer are additives in hair relaxer products.

How Do Chemicals in Hair Relaxers Cause Cancer?

Hair relaxers contain potent chemicals known as endocrine disruptors (EDCs). These chemicals can be absorbed into the body through inhalation or skin contact during hair straightening.

When the chemicals contact the blood vessels around the scalp, they are easily absorbed into the body since the vessels around the scalp are closest to the skin’s surface and carry more blood than any other part of the skin.

Scalp burns from the consistent use of hair relaxers can also provide an easy entry for toxic chemicals. Once inside the body, the chemicals disrupt the production of hormones responsible for various crucial functions in the body, such as:

  • Cell growth
  • Reproduction or fertility
  • Immune system control

Cancer cells in the female reproductive organs, such as the uterus, often grow faster due to this disruption. Many hair product manufacturers get away with using such toxic chemicals by hiding them under general terms such as “fragrance.”

What are the Main Cancer-Causing Chemicals in Hair Relaxers?

Hair straighteners contain some toxic chemicals suspected to increase the risk of cancer in women.

A NIH Sister Study involving 33,000 women to assess risk factors for cancer in women showed that women who used hair straightening products were twice as at risk of developing uterine cancer as those who didn’t. Surprisingly enough, no other hair products, such as dyes, highlights, and perms, had the same effect on the uterus at the end of the experiment.

Do relaxers cause health problems? More importantly, what chemicals in hair relaxers could make them so potent? Below are three toxic chemicals in many hair relaxers today:


Formaldehyde is a chemical present in many hair straighteners. In some ingredient lists, it also appears under various aliases, such as formalin or methylene glycol. The chemical causes severe irritation and respiratory issues upon inhalation.

It also causes scalp burns and headaches when in contact with the skin. While OSHA requires businesses, for example, salons that deal with formaldehyde, to warn customers of its cancer-causing properties, many still don’t.


Phthalates are another harmful chemical in many hair relaxers. They’re used as plasticizers to make hair straighteners more durable and flexible and are well-known endocrine disruptors that impact hormones.

Di-2-ethyl hexyl phthalate (DEHP) is the most dangerous phthalate in many straightening products. It is a well-known carcinogen that causes reproductive issues, infertility, endometriosis, and various reproductive cancers.


Parabens are a chemical used to preserve many cosmetic products, including hair straighteners. They’re an endocrine disruptor, with several studies showing they can mimic estrogens and increase the risk of reproductive cancer cell growth.

Who is at the Most Risk of Cancer from Hair Relaxers?

Note that all women who use hair relaxers with toxic compounds are at risk of getting uterine cancer, regardless of race. However, studies show Black women are more exposed to relaxers or straightening products from an early age and use them frequently throughout their lives.

Sadly, some straighteners marketed and sold to the Black community contain toxic chemicals.

Contact Elrod Pope Accident & Injury Attorneys for a Free Case Evaluation

Some manufacturers fail to warn consumers of their chemical hair relaxer’s side effects. As a result, many women end up with reproductive conditions that are painful and costly to manage and treat.

If you or a loved one has been diagnosed with uterine cancer or uterine fibroids after using hair relaxers, our attorneys at Elrod Pope Accident & Injury Attorneys can help you get the compensation you deserve. We can help pursue a hair relaxer settlement with manufacturers who designed their products with toxic chemicals.

We will represent you if cases proceed as anticipated so you can get full compensation for:

  • Medical bills
  • Lost wages
  • Pain and suffering
  • Diminished working capacity
  • Emotional distress

Contact us today for a free evaluation of your case today.

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