Hair Relaxer Side Effects

Potential Side Effects of Hair Relaxers

Chemical hair straightening products change the actual structure of your hair. These products often involve multiple processes and applications to the scalp. If you used chemical hair straighteners or relaxers, you may experience any number of uncomfortable, potentially dangerous, side effects. Additionally, your risk of developing uterine, endometrial, and ovarian cancer significantly increases. Some of the potentially dangerous side effects may include: ⁽¹⁾

• Lung damage.
• Reproductive disorders.
• Uterine fibroids.
• Baldness.
• Early onset menstrual cycles and breast development.
• Burns, wherever the chemicals touch.
• Lesions.
• Scalp irritations.
• Alopecia.

Lesions and burns on your scalp expose your skin to irritants. Toxic chemicals can enter your body and bloodstream more easily. ⁽²⁾

Other, more general, potential side effects of using chemical hair straighteners or relaxers include: ⁽³⁾

• Central nervous system effects: Headaches, dizziness, nausea, and drowsiness.
• Numerous cancers: Severe complications due to formaldehyde alone, such as blindness. 
• Lung irritation: Difficulty breathing, shortness of breath, coughing, and swelling of lung tissue.
• Nose and throat irritation: Runny nose, scratchy throat, burning, and itching.
• Allergies: Stuffy or runny nose, sneezing, skin allergic reaction, and asthma.
• Eye irritation: Redness, watering, itching, and burning.
• Skin irritation and dermatitis: Redness or itchiness, as well as rashes and dry, cracking skin. 

Hair Relaxers and Cancer

Some studies suggest chemical hair straightening products “may contain hazardous chemicals with endocrine-disrupting and carcinogenic properties.” These chemicals put women at risk of developing reproductive-related cancers, such as uterine, endometrial, and ovarian cancer. ⁽⁴⁾

Uterine Cancer

Studies indicate that in the United States, chemical hair relaxers are linked to uterine cancer. The National Institutes of Health (NIH) reports that the incidence “rates of uterine cancer have been rising … particularly among Black women.” ⁽⁵⁾

Use of chemical hair straightening products is “associated with a higher risk of hormone-sensitive cancers,” including ovarian. ⁽⁶⁾ Researchers for the NIH looked at nearly 34,00 women from 35 to 74 years of age. They identified 378 women who had developed uterine cancer. ⁽⁷⁾ 

Women who frequently used these products were more likely to develop uterine cancer than women who had never used a chemical hair straightening product. ^{(8) (9)} 

The NIH study “found that women who reported frequent use of hair straightening products, defined as more than four times in the previous year, were more than twice as likely to go on to develop uterine cancer compared to those who did not use the products.” Specifically, roughly 1.64% of women who never used chemical hair straighteners went on to develop uterine cancer by age 70. However, for frequent users, that risk went up to 4.05%. ⁽¹⁰⁾

In fact, women who had reported using chemical hair straighteners frequently “were about 2½ times more likely to develop uterine cancer.” A major concern is that some of the chemicals used in hair straightening “products might be absorbed through the scalp and have estrogen-like properties in the body.” ⁽¹¹⁾

Black Women and Uterine Cancer

In the NIH study, approximately “60% of the women who reported using straighteners … self-identified as being Black. …the effects may be greater for Black women because they’re more likely to use these products.” ⁽¹²⁾

Not only do Black women report using chemical hair straighteners more frequently, but they also tend to start using these products at earlier ages. ⁽¹³⁾

Self-identified Black women reported using chemical hair straightening products more than women of other races. Because of the frequency of use, they “were at higher risk for uterine cancer compared to women who did not report using these products.” Also, the researchers of the NIH study found that while hair straighteners did put you at risk of developing uterine cancer, other hair products did not — this included bleach, perms, hair dyes, and highlights. ⁽¹⁴⁾

Ovarian Cancer

Chemical hair straightening products may be linked to ovarian cancer. These chemicals also are “endocrine disruptors that can be absorbed into the bloodstream.” ⁽¹⁵⁾

Researchers studied roughly 40,500 participants from 35 to 74 years of age. Participants completed questionnaires about their use of specific hair care products, including straighteners and relaxers. ⁽¹⁶⁾

“Over a mean follow-up of 10 years, 241 women were diagnosed with ovarian cancer.” Frequent use of chemical hair straighteners and relaxers was associated with ovarian cancer risk. Frequent use was defined as four or more times in 12 months. ⁽¹⁷⁾

Black Women and Ovarian Cancer

Women who self-identified as African American or Black were more likely to use chemical hair straightening products more frequently than woman of other races. These women seemed to face a greater risk of developing ovarian cancer. ⁽¹⁸⁾

The dangerous chemicals used in hair straightening or relaxing products include “a range of endocrine disrupting compounds that are potentially of concern, including phthalates, parabens, cyclosiloxanes, and metals, in addition to formaldehyde.” ⁽¹⁹⁾

Endometrial Cancer

“Endometrial cancer is also the most common form of uterine cancer, so it is frequently referred to as uterine cancer.” But endometrial cancer is its own specific type of uterine cancer. ⁽²⁰⁾

The endometrium is the lining of the uterus. Cancer of the endometrium is different from other types of uterine cancer that can originate in the connective tissue or muscle of the uterus. Approximately 80% of all endometrial cancers are a type called adenocarcinomas. This type develops in the glands in the endometrium. One possible cause of endometrial cancer is hormonal imbalance. ⁽²¹⁾

Blacks and Latinas Targeted for Hair Relaxer Use

Narrow beauty standards put women of color, include Blacks and Latinas, at risk of being harmed by chemical hair straightening products. They are the targeted demographic for chemical hair straighteners. ⁽²²⁾

Women of color are fed “backwards beauty standards and messages” about their bodies. The underlying message is straight (“White”) hair is beautiful. Curly (“Black”) hair is not. ⁽²³⁾

These women often feel pressured into using these dangerous chemical hair straightening products at a young age — and for many years to come. These products become a common and integral part of their beauty routine. And, as a result, Blacks and Latinas unknowingly put themselves at risk for developing reproductive cancers and other horrendous side effects. ⁽²⁴⁾ 

Major Ingredients in Chemical Hair Relaxers

The danger of chemical hair straightening products lies with the chemicals themselves. These harmful ingredients include, but are not limited to: ⁽²⁵⁾

• Formaldehyde — This chemical is dangerous, in and of itself. It poses even more risks to salon workers who inhale the fumes for long periods of time. Long-term exposure may increase your risk of developing cancer.
• Sodium hydroxide — Also commonly known as lye, sodium hydroxide breaks the disulfide bonds in your hair. High concentrations can lead to burns and temporary hair loss, as well as skin, eye, and lung irritation. 
• Parabens — All parabens used for commercial purposes are endocrine-disrupting chemicals. Often, multiple chemicals are used in just one product. Common parabens include methylparaben, ethylparaben, propylparaben, and butylparaben. 
• Cyclosiloxanes — Cyclosiloxanes are used in multicomponent hair relaxer kits. Exposure to these chemicals can injure skin and harm your reproductive system.
• Phthalates — Diethylphthalate and diethylhexylphthalate can be inhaled or absorbed through the skin. Phthalates can affect your reproductive and endocrine systems. 
• Benzophenone-3 — Benzophenone-3 is also known as oxybenzone. You find this chemical in the conditioner component of hair relaxer kits. It is also in temporary hair straightening products. This chemical may disrupt your endocrine system. 
• Diethanolamine — This is a contaminant of ingredients used in hair straightening products. It is commonly found in the shampoo portion of the kit. Diethanolamine can form cancerous chemicals when it reacts with product impurities.
• Triclosan — Studies suggest triclosan may disrupt your endocrine system. You can absorb this substance through the skin. 

Other dangerous chemicals in hair straightening products can include: ⁽²⁶⁾

• Isopropyl alcohol.
• Hydrogen peroxide. 
• Ammonium hydroxide.
• Ammonium thioglycolate or glycerol monothioglycolate.
• Boric acid, perborate, and borate.
• Bromates. 
• Guanidine carbonate.