Can using everyday hair care products be harmful to your health?

A few recent studies have called into question whether certain hair care products and treatments are safe and if using them puts your health at risk. According to recent Purdue University research published in Environmental Science & Technology, several chemicals — most notably a group called cyclic volatile methyl siloxanes (cVMS) — that are commonly found in everyday hair care products easily evaporate and linger in the air after they’re applied. The researchers discovered that an average hairstyling session at home could result in someone inhaling between 1 and 17 milligrams of these chemicals, which researchers say are potentially hazardous to your health.

The researchers also learned that using a curling iron or a flat iron and applying high heat to hair that has been treated with these products can intensify the release of these chemicals.

So what do these findings mean for the millions of people who regularly use hair care products and hot styling tools? Read on and find out.

What’s happening?

While previous environmental studies have focused on the siloxanes found in wash-off personal care products like shampoo and shower gel — meaning they’re rinsed off after applying — the researchers wanted to analyze these chemicals with respect to leave-in hair products, including hair gels, oils, creams, waxes and sprays.

Researchers gathered volunteers between the ages of 18 and 65 who regularly use leave-in hair care products, and instructed them to perform their typical styling routine in the university’s lab. “It’s a protected environment with a very controlled atmosphere where we can detect the composition of the air every fraction of a second,” lead author of the study Nusrat Jung, assistant professor at the Lyles School of Civil Engineering at Purdue University, tells Yahoo Life.

Before, during and after hairstyling, Jung and her colleagues measured real-time emissions of volatile organic compounds (VOCs), which included siloxanes. They found that the most abundant chemical that lingered in the air was decamethylcyclopentasiloxane, otherwise known as D5 siloxane (or cyclopentasiloxane) — an ingredient used in most hair care products for its ability to make hair smooth and shiny.

“A styling routine that mixed these chemicals with a heated appliance further exacerbated the release of this product into the air,” says Jung. When the study participants used a hot styling tool that reached 210 degrees Celsius/410 degrees Fahrenheit, the chemical emissions from the hair care products increased anywhere from 50% to 310%.

“I was extremely surprised to see such significant emissions of volatile chemical mixtures coming from off-the-shelf hair care products,” says Jung, who has been using these items to style her own curly hair. “If I go to a salon for a hair treatment, for example, I’m expecting to be exposed to chemicals. But I really did not expect that this would happen if we were to replicate our everyday hair care routine.”

Do I need to worry?

It’s important to point out that there is minimal science on whether D5 siloxane poses any health risks to humans — most of the research on its potentially harmful effects are on animals. The Environmental Working Group scores ​​cyclopentasiloxane as a 3 out of 10 on its toxicity scale, with 10 being the worst.

However, Jung explains that D5 has already been classified as “very persistent and very bioaccumulative” — meaning, the substance doesn’t break down easily in the environment and can gradually build up in humans and animals — by the European Chemicals Agency. So it’s unclear whether that might be harmful with frequent use over time.

“When you’re taking a shower with wash-off products, this water is getting treated and going somewhere, which is why it was detected in small animals and marine animals,” she says. In 2015, a study conducted in the Netherlands showed that inhaling D5 siloxane from personal care products can lead to adverse effects on the respiratory tract, liver and nervous system of laboratory animals. Jung also notes that “the whole continent [of Europe] has restricted this chemical formulation.”

This isn’t the first time hair products have come under scrutiny. In October, a study from Boston University found an association between chemical hair relaxers and an increased risk of uterine cancer. As a result, the Food and Drug Administration plans to propose a ban on formaldehyde (FA) and other FA-releasing chemicals as an ingredient in hair smoothing and hair straightening products marketed in the U.S.

“Results from our analysis in the Black Women’s Health Study showed that postmenopausal women who reported using hair relaxers more than twice a year or for more than five years had a greater than 50% increased risk of uterine cancer compared to women who never or rarely used hair relaxers,” Kimberly Bertrand, co-author of the study and associate professor of medicine at Boston University’s Slone Epidemiology Center, previously told Yahoo Life. Postmenopausal Black women who used hair relaxers for 20 years or more had about a 70% increased risk of uterine cancer compared to never or light users.

What can I do about it?

D5 is generally considered safe to use. But if you’re concerned, Jung stresses the importance of having proper ventilation when using everyday hair products that may contain D5. “Wherever you are conducting your hair care routine, put on an exhaust fan,” she urges. “The volatile chemicals will be sucked out from the fan and may be able to remove at least 90% from your indoor space, so this is very good news.”

However, she points out that turning on an exhaust fan simply means these emissions go “from one space to another — they do not disappear. Siloxanes have already become a part of the atmosphere, which means we are contributing to pollution.”

You can also try applying hair care products and doing chemical relaxing treatments less often. (Research links the greatest risk of gynecological cancers with moderate to heavy use of chemical relaxers.) Reading the ingredients on your hair care products is another possible option, but it may be a somewhat challenging task. “There’s D5 as well as other compounds we found known as D4 and D3, which fall into the cVMS category,” Jung explains. “The chemicals have long names, but all of these names end with the word siloxanes.”

However, she adds that hair care manufacturers may not disclose every ingredient included in a product. “They have the right to retain that information.”

Although it’s easier said than done, avoiding leave-in creams, sprays and gels may be the most effective way to protect yourself, as well as the environment.

The main takeaway

As with any research, there are some variables to consider. How often these products are used, how much time a person’s hair care routine takes, the temperature of styling tools, hair length, bathroom size and type of ventilation system are all factors that affect how much chemicals may be inhaled.

Jung is hopeful that these latest findings will lead to more research and raise awareness not only among consumers, but also within the hair care industry and the scientific community. “I think we simply need to work toward better understanding in characterizing what impact these chemicals may have on human health,” she says. “My hope is that we can see this as an opportunity to conduct more research.”

“I want to share this information with the public,” says Jung, explaining that it’s not her intention to scare anyone. “I want them to be aware of it, be cognizant of it and do what they can to protect themselves.”