Billions of dollars are spent on hair care products and services every year in the U.S. alone.
But, while glossy, blow-dried hair might look strong and sleek, the products you use to style it could be giving you cancer.
Hair Products and Cancer: What’s the Link?
“Toxic chemicals in hair products are quite common,” Adana Llanos, a professor in cancer and molecular epidemiology at Columbia University’s Irving Medical Center, told Newsweek.
“Some of the chemical ingredients found in hair products—including hair dyes and chemical relaxers and straighteners—have mutagenic and carcinogenic properties, meaning that they can cause harmful changes and/or damage to the DNA that can promote the development of cancer cells.”
One known carcinogen that has been found in a range of beauty products, including dry shampoo and other aerosols, is benzene.
“Benzene is a known human carcinogen,” Kelly Johnson-Arbor, Medical Director at the National Capital Poison Center, told Newsweek.
“Recent testing of dry shampoo products found that, when sprayed, some of these products contained benzene in concentrations of up to 158 ppm, or nearly 60 times the FDA [Food and Drug Administration] allowable limit of benzene in pharmaceutical substances,” she added.
The FDA allows up to 2 ppm of benzene to be present in pharmaceutical preparations if the use of benzene is unavoidable. However, this recommendation only applies to drug products with “significant therapeutic advance.”
In most cases, this does not include hair care.
While the specific effects of benzene exposure from hair products have not yet been studied, the chemical is known to damage the immune system and alter the DNA in bone marrow cells, which can lead to leukemia and other blood cancers.
In October, Unilever issued a voluntary recall of 19 dry shampoo products due to possible benzene contamination, following a similar recall by Procter & Gamble in December. However, many other products with detectable levels of benzene are still on supermarket shelves.
The chemicals in hair products can cause cancer indirectly too, Llanos explained.
“Other hair products including various types of styling products, leave-on and rinse-off conditioners, hair oils, etc., often contain chemicals that alter our normal hormone levels called endocrine-disrupting chemicals,” she said.
“[These] can impact our risk for hormone-related health outcomes, including breast, ovarian, uterine cancer. Emerging evidence suggests that there are associations between hair product use and prostate cancer risk as well.”
Chemical Straighteners and Cancer
One particularly concerning group of products are chemical hair straighteners.
A study published in October in the Journal of the National Cancer Institute found a significant association between the use of hair straightening products and uterine cancer, and previous studies have also linked straightening products to other hormone-related cancers, such as ovarian and breast cancer.
The study, which included data from 33,497 U.S. women over the course of 11 years, found that women who used chemical straighteners were more than twice as likely to develop uterine cancer than those who did not.
“The study’s authors suggested that the chemical ingredients in hair straightening products, including formaldehyde and heavy metals, may be responsible for at least part of this increased risk,” said Johnson-Arbor, who was not involved in the study.
Who Is At Risk?
Although the association between straighteners and uterine cancer in the aforementioned study did not differ by race, the association was more pronounced in Black women: despite making up only 7.4 percent of the study population, 60 percent of the participants who had used chemical straighteners were Black women.
“The use of hair straightener products varies among ethnic groups, and people who use hair straightener chemicals on a regular or frequent basis may have a higher cancer risk because of this,” Johnson-Arbor said.
Llanos said the disproportionate impact of hair products on Black women was not isolated to chemical hair straighteners.
“Black women spend substantially more money on cosmetics and hair products annually than other demographics in the U.S., and evidence shows that a large proportion of products marketed to Black women are among the most toxic,” she said.
For example, a study in 2018 found that products marketed at Black women contained higher levels of parabens and phthalates (both known endocrine disruptors) when compared to those marketed at white women.
“I would say that Black women are more at risk of exposure to chemicals found in personal care products, particularly our hair products, than other groups,” Llanos said.
Salon workers are also particularly vulnerable to these toxic chemicals due to their high levels of exposure in often poorly ventilated areas.
A study in 2014 by Women’s Voices for the Earth, an NGO working to reduce the impacts of toxic chemicals in products aimed at women, found that salon workers are at a greater risk of certain health problems compared to other occupations, including cancers, birth defects, reproductive disorders, asthma and immune disease.
Several studies have found bladder cancer to be between 20 and 30 percent more prevalent among hairdressers, and research conducted in Brazil, where hair straightening products are very popular, found that DNA damage was 30 percent higher in hairdressers compared to other members of the population.
This increased risk is likely to be, at least in part, due to the inhalation and absorption of toxic chemicals found in beauty products.
How to Minimize Risk of Cancer From Hair Products
While the ingredients of cosmetic products in the U.S. are regulated by the FDA, dangerous contaminants, like benzene, can unintentionally be introduced during the manufacturing process.
“The United States FDA regulates cosmetic products, including shampoo and hair dyes, but does not test these products to prove that they are safe,” Johnson-Arbor said. “Instead, cosmetic product manufacturers are responsible for ensuring that the products they sell are safe.
“As there has not been widespread testing of hair products, it’s difficult to know if a certain dry shampoo, conditioner, or other hair product contains carcinogenic compounds like benzene.
“To limit your exposure to benzene and/or if you are concerned about exposure to carcinogenic chemicals in hair products, use hair sprays and other aerosol products—like dry shampoo—in well-ventilated areas and use the products as sparingly as possible.”
When it comes to cosmetics, chemical safety standards in the U.S. are less strict than in other places such as the European Union. Llanos said: “The regulation of toxic chemicals in the U.S., at the federal level, appears more lax than elsewhere including the E.U.
“It is puzzling that personal care products sold in the U.S. contain thousands of toxic chemicals and chemicals of concern, while these same chemicals are completely banned or heavily regulated in the EU.
“I think consumers should be concerned about this.”
When it comes to product safety, Llanos recommended referring to the Campaign for Safe Cosmetics. The campaign’s Non-Toxic Black Beauty Project is specifically aimed at Black women and provides a database of non-toxic Black-owned beauty products.
“This resource contains a wealth of information and might help empower women to make safer choices when buying products for themselves and their families,” Llanos said.