Learn the Benefits of a Luxurious Keratin Hair Treatment

Is the Formaldehyde in Brazilian Hair Straightening Safe?

studioportrait of girl with windblown hair
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Keratin hair treatments (also known as Brazilian hair treatments) smooth out and straighten wavy or curly hair. They're very popular, but these treatments rely on formaldehyde (a known carcinogen when inhaled), are also very controversial.

How It Works

Keratin is a protein that is naturally found in hair. It is not, however, responsible for taming the frizz that this treatment is famous for. That job relies on the formaldehyde found in the formula. It locks the chains of keratin proteins into a straight line, which leaves your hair nice and straight once the treatment is complete.

During the treatment, a stylist will apply a keratin product to your hair while she carefully avoids getting any on your scalp. The product remains in the hair as it's blow-dried and then flat-ironed.

There are many versions available to salons and some contain more formaldehyde than others, while some newer treatments contain less harmful alternatives. Since formaldehyde is a gas, it is most dangerous when it goes into the air and is inhaled. For this reason, some stylists wear masks as they do the treatment and they may have you wear one, too. Treatments are usually done in a location with extra ventilation as well.

The treatments usually take two hours or longer, depending on the length and thickness of your hair.

Afterward, you may not be able to wash your hair for up to three or four days. Different products will vary, so be sure to ask your stylist how long you need to wait before shampooing.

It is very important that you switch to a sulfate-free shampoo and avoid sprays designed to create beachy waves as well. Anything that contains sulfates or salt can counteract the frizz-free look the treatment provides and shorten the life of the straightener's effects.

The Best Candidates

Unlike some hair straightening treatments, keratin treatments can be done on color-treated hair. They work well on people (men get them, too) with wavy to tight curly hair. If you are tired of fighting frizz, you'll love the results from the keratin treatments—they even get rid of frizz in humid or rainy weather.

You should not get a formaldehyde-containing treatment if you're pregnant or even just trying to have a baby. The CDC states that inhaling the gas can cause fertility problems, including miscarriage.

Also, it is not recommended to get these treatments more than two or three times a year. If you go more often, you will jeopardize the health of your hair because it may become brittle and break easily.

The Cost

The cost of keratin treatment varies from city to city. It depends a lot on the poshness of the salon (high-end salons charge more), but they typically range from $300 to $800.

When choosing a salon, the price should not be your only consideration. The expertise of the stylist is vital to getting great results and protecting your health. Ask questions and get recommendations in your area to find someone who has a lot of experience and is highly skilled in the process.

Straight Hair for Months

The treatment usually lasts about two to three months, or a bit longer. And you should not expect the pin-straight hair you get with the Japanese straightening treatment.

You will have to blow-dry or flat-iron your hair to get it to really straight, or you can let it air dry into soft waves. However, your blow drying time will be cut down by about 40 to 60 percent thanks to this treatment.

Keratin Treatment vs Brazilian Hair Straightening

Back in the early 2000s, a buzz began generating around New York City about Brazilian hair straightening. It was the hot new thing from Brazil and women with curly hair were loving it even more than the more permanent Japanese treatments.

The Brazilian promised glossy, sleek hair that maintained some of its volume. Plus, it worked on color-treated hair and lasted two to three months. The Japanese process left you with stick-straight hair for about six months until your own curly hair grew back in. 

For a couple years, Brazilian treatments were the ones to get if you had wavy or curly hair that you wanted to smooth out or straighten. Popular brands included Brazilian Keratin Treatment, the Brazilian Blowout, and Brazilian Hair Straightening. The word "Brazilian" was the term that sold it.

And then word got out about the amounts of formaldehyde found in these products. The levels were so high that it was dangerous, especially for the beauticians working around the chemicals all day.

So what happened? Brands changed their marketing tactics. Instead of plugging the "Brazilian" bit, they started promoting the keratin part of the formula. After all, these treatments all contain a lot of keratin, which is naturally part of healthy hair. All wording about formaldehyde disappear and they got away with it because the FDA and other agencies do not regulate salon treatments in the U.S.

Safety Concerns

The real question is whether or not these treatments are safe, and that is up for debate. Many women get the keratin treatments a couple times a year and have no known issues. They feel the results are well worth the risk.

If you do opt to try a treatment, be sure to have it done by someone who specializes in keratin treatments. If your stylist uses a flat iron that's too hot, for example, she could damage your hair. And you want someone who knows exactly what's in the product the salon uses. 

Some keratin brands market themselves as "formaldehyde-free," though tests have proven that a number of these do contain some amount of the toxin. For a traditional keratin treatment to work, some formaldehyde will be in the product. How much is what matters. An honest and experienced stylist will know how much formaldehyde is in the treatment used on you.

Experts are in agreement that the main danger is not to those getting the treatment, but to those giving the treatment. Some beauticians work with potentially poisonous gasses several times a week. What effects the formaldehyde will have on them is still unknown.

100% Formaldehyde-Free Alternatives

As noted in Allure, there are now alternatives to formaldehyde in keratin treatments. These offer the same smooth texture, but the hair is locked into place with glyoxylic acid. Ask your stylist if she has the option of using brands like Goldwell Kerasilk or Trissola Solo, which are 100 percent formaldehyde-free.

Another salon option is Keratin Complex. The company offers a few different formulas, from a classic smoothing treatment to one for fragile hair. These are actually designed to repair damaged hair, not straighten it. Yet, that alone could help tame your frizz without the cost or risks involved with straightening.

There are also keratin-based home treatments that can provide the same results. Generally, any of these alternatives will not last as long as formulas that contain formaldehyde.


Centers for Disease Control and Prevention. Reproductive Health and the Workplace: Formaldehyde. 2017.

Environmental Working Group. Brands That Hide Formaldehyde. 2011.

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