Why You Should (or Shouldn’t) Get a Keratin Treatment

Stronger than your average smoothing serum but not quite as intense as a Brazilian blowout, keratin treatments are a favorite in the hair care world for their ability to turn dry, frizzy hair into gorgeously shiny, manageable tresses. The treatments can fight stubborn frizz in even the most humid, hair-fluffing climates, and they prep your locks to create a perfectly smooth, long-lasting blowout. 

However, these treatments aren’t for everyone. If done incorrectly or on the wrong hair type, keratin treatments risk doing more harm than good. We consulted with hair care experts to see who could benefit the most from this treatment — and who might want to opt for something else. Here’s what you need to know. 

What Is a Keratin Treatment?

Keratin is a naturally occurring protein in our hair, nails, and skin. But over time, environmental factors, styling with heat, and the general aging process deplete our body’s supply of the protein. As a result, hair can become dull and prone to breakage. Keratin treatments restore the hair’s keratin supply by applying the protein directly to the hair shaft and setting it with heat.

According to Steven Lightfoot, technical director for Peter Coppola Beauty, a keratin treatment involves two main steps: the keratin application and the heat setting. After the keratin concentrate is applied to the hair and allowed to develop for up to 50 minutes, the protein is set into the hair shaft with heat by a blow dryer and/or a flat iron. 

“The keratin treatment isn’t shampooed out. It coats your hair, and it smooths everything out,” dermatologist Alok Vij, M.D., told the Cleveland Health Clinic. “And then the heat seals it, or cures it, to help restore that outer layer to a glossy, shiny, smooth texture.” Per Lightfoot, this protective keratin topcoat results in up to 85% frizz reduction over the life of the treatment, which is up to six months — though it may be shorter if you wash your hair often. 

Do Keratin Treatments Straighten Hair?

Keratin treatments’ smoothing and anti-frizz properties can cause some hair to appear straight, but this process isn’t technically meant to straighten, according to Zoe Passam, senior trichologist at Philip Kingsley. If you already have a loose wave pattern, your frizz-free hair might look straighter post-treatment. But those with tight curls or wave patterns will only see a loosening of their curls with some movement still visible in the hair shaft. 

The process shouldn’t be confused with chemical straighteners and relaxers, which use chemicals to break down the protein structure of the hair shaft to disrupt the curl pattern for smoother, straighter locks. This is a permanent straightening. Keratin treatments don’t break down protein; they add protein to the hair, and the results are temporary. Because of this, keratin treatments are considered a less intense version of a similar smoothing treatment called a Brazilian blowout. 

 How Is a Brazilian Blowout Different? 

If you want a smoothing treatment that will definitely straighten your hair, then a Brazilian blowout might be right for you. Although the process is similar to a keratin treatment, there are a few notable differences. According to TikTok hair expert Laci Rae, one of the main differences between a Brazilian blowout and a keratin treatment is that keratin treatments use protein, while Brazilian blowouts use amino acids — the building blocks of protein. 

The amino acids’ smaller molecular structure allows them to permeate the hair shaft more deeply and create an even sleeker, straighter appearance. This subtle formula change also means Brazilian blowouts are set immediately upon application. Unlike keratin treatments, which require up to three days of strict rules where you can’t wash, crimp, or otherwise crease your hair, Brazilian blowouts are ready to be worn in as soon as you leave the salon. 

“You can even go swimming,” Rae says. “Not that I would recommend it, putting chlorine in your hair, but you could if you really wanted to. It’s pretty cool.” Unfortunately, because it’s a more intense treatment, hair is more prone to breakage and other hair health issues over time. 

Can You Get a Keratin Treatment on Color-Treated Hair? 

Experts vary on whether it’s safe to get a keratin treatment on color-treated hair, and information gets even more muddled when considering whether to apply the treatment before or after the color. Anthony Dickey of Hair Rules salon says that, generally speaking, a keratin treatment will not alter the chemistry of your hair color — with some exceptions. 

According to Dickey, many variables come into play with regard to combining keratin and color treatments, including the damage level of the hair and the shade of hair dye. For example, some hair color might lighten or become more saturated after the heat-setting phase of a keratin treatment. “It’s not a one-size-fits-all approach question,” Dickey explains, suggesting that anyone looking to combine treatments should consult their hair care professional first.

To wit, celebrity hairstylist Joseph Michael says that on people with blond hair, a keratin treatment can cause a bit of brassiness, so he likes to do the treatment before his client’s next color service. 

Who Should Get a Keratin Treatment? 

According to Michael, people with curly, wavy, or frizzy hair are good candidates to get a keratin treatment “in order to make their hair more silky and manageable.” Whether your hair naturally frizzes on its own or is caused by humid climates, keratin treatments can help mitigate the risk of your hair turning into a giant poof ball the second you walk outside. Because you’re less likely to use heat styling tools to prevent a frizz flare-up, keratin treatments also help prevent future damage to your hair. 

Keratin treatments’ smoothing qualities significantly cut down styling time, making them a fantastic choice for low-maintenance people who want to be able to brush their hair and get out the door. However, these results might not be applicable to all hair types. 

Who Shouldn’t Get a Keratin Treatment?

Keratin bond extensions use thin strands of unprocessed human hair affixed with keratin protein on the end that attaches to a person’s actual hair. When heat is applied to the keratin protein, it fuses with the hair and creates a seamless, invisible bond. These extensions take longer to apply than clip-in or sewn-in extensions, but lead to perfectly blended results — as demonstrated by Irish hair educator Coia Styles on TikTok. 

Individuals who are pregnant and breastfeeding also should avoid keratin treatments, due to the formaldehyde commonly used in these formulas. A 2017 study published in Medicine found that formaldehyde exposure has been linked to a higher risk of congenital anomalies. The CDC states that while it’s unclear how much formaldehyde can be transferred to infants through breast milk, it’s safer to reduce or eliminate exposure as a precaution. 

Should You Be Worried About Formaldehyde Even If You’re Not Pregnant? 

If putting formaldehyde on your head gives you pause, you’re not alone. The American Cancer Society has deemed formaldehyde carcinogenic, and other side effects from exposure to this chemical can include watery eyes, coughing, wheezing, nausea, and skin irritation. However, formaldehyde is one of the key ingredients in virtually all keratin treatments on the market. The levels should be low enough to be safe, though, as approved by the FDA. Don’t go to any salon using a brand that’s not regulated.

There are some formaldehyde-free options on the market, but they might not be as effective in achieving that smooth glossiness. Moreover, the companies might be fibbing about the levels. A 2011 study published in the Journal of Occupational and Environmental Hygiene found that even keratin treatments that were labeled to be formaldehyde-free “have the potential to produce formaldehyde concentrations that meet or exceed current occupational exposure limits."

Formaldehyde is also present in most hair dyes, so if you’re used to getting your hair colored regularly, then the risk of formaldehyde exposure probably won’t be a dealbreaker for you. However, if the idea of formaldehyde still makes you uneasy, you can achieve similar (but shorter-lasting) results to a keratin treatment with a blow dryer, flat iron, or smoothing products like serums, oils, and masks. 

Even though keratin treatments aren’t quite as intense as getting your hair permed or chemically relaxed, you should still consult a trusted hair care professional before using them. A hairstylist can assess your hair’s specific weight, thickness, porosity, and susceptibility to damage to determine whether a keratin treatment is right for you.