Brazilian blowouts are advertised to get rid of frizz and give you smoother, stronger, and shiner hair. However, researchers warn that some of the chemicals in a Brazilian blowout treatment may be harmful to your health.

This professional hair smoothing treatment is sometimes called a Brazilian keratin treatment or BKT. Brazilian Blowout is also a brand name for this salon treatment. Other keratin hair treatments may carry the same risks.

A Brazilian blowout creates a protective layer around each strand of hair. It uses a liquid keratin formula. Keratin is a kind of protein naturally found in your hair, skin, fingernails, and even teeth.

Adding more keratin can help strengthen and smooth hair strands. This temporarily makes your hair look fuller and glossier.

This protein is also found in horns, hoofs, claws, feathers, and wool. The keratin used to make Brazilian blowout treatments usually comes from birds and animals.

Other chemicals are also needed to help bond keratin to your hair.

potential chemicals in Brazilian blowout products

Ingredients in a Brazilian blowout may include chemicals like:

  • formaldehyde
  • formalin
  • methylene glycol
  • methylene oxide
  • paraform
  • formic aldehyde
  • methanol
  • oxymethylene
  • oxomethane
  • CAS Number 50-00-0
  • timonacic acid
  • various perfumes or scents

Brazilian blowout formulas may also include natural plant ingredients that come from Brazil, such as:

  • acai berry
  • annatto seed
  • camu camu

The Food and Drug Administration (FDA) warns that Brazilian blowouts and other hair-smoothing products can cause serious side effects.

Symptoms are more common in stylists and other people working with these treatments.

A comparison study found that Brazilian Blowout solution is almost 12 percent formaldehyde. This almost three times higher than other brands of keratin hair treatments.

You may also have a reaction after getting a Brazilian blowout. Symptoms can happen while you’re getting the treatment or may begin hours or even days later.

Side effects include:

  • headaches
  • dizziness
  • breathing problems
  • nausea
  • vomiting
  • chest pain
  • itching
  • rash
  • scalp burning
  • blisters
  • nose or throat irritation
  • eye stinging or redness
  • watery eyes
  • nosebleeds

Stylists typically use a blow-dryer and hair straightener to seal in the keratin in a Brazilian blowout treatment.

The heat causes chemicals to be released into the air through the hot fumes. If you have asthma or are more sensitive to breathing chemicals, this may trigger symptoms like wheezing.

A Brazilian blowout may not be good for your hair in the long run. Some people have hair problems after getting this and other types of chemical straightening treatments. You may have:

  • hair breakage
  • dry, brittle hair
  • hair loss
  • hair patchiness

A comparison study found that Brazilian Blowout brand solution contains 11.5 percent formaldehyde. This is almost three times higher than three other brands of keratin hair treatments.

The FDA officially classified formaldehyde as a cancer-causing chemical in 1987.

Formaldehyde and formaldehyde-releasing chemicals are harmful to people. The National Toxicology Program warns that formaldehyde is a cancer-causing chemical.

Brazilian blowouts are quite new. They were first sold in 2006. However, formaldehyde was known to be a dangerous chemical since 1980.

A study from Brazil found that a Brazilian blowout treatment can cause skin problems. Seven people in the study had scalp rashes after their hair treatment.

Other people had eczema-like rashes and blisters on the scalp, face, neck, upper arms and even the upper chest and back. According to the researchers, chemicals in the Brazilian blowout treatment can cause serious skin and scalp reactions. The skin conditions were more like drug reactions than an allergy.

Formaldehyde may raise your risks of some kinds of cancers if you’re exposed to it enough. This chemical may trigger leukemia and cancers of the nose.

Avoid getting a Brazilian blowout or other chemical hair treatments if you’re pregnant.

One study found that using hair dyes and hair-straightening treatments during pregnancy may be linked to some types of leukemia in children under the age of 2 years.

If you experience any symptoms or a reaction while having a Brazilian blowout, ask your stylist to stop the treatment immediately. Ask the stylist to wash out any product in your hair. Also, be sure to wash your hands and face.

Move to a well-ventilated area or go outside if you can. Removing any chemicals from your skin and scalp may help reduce skin rashes. Getting away from chemical fumes may help breathing, nose, and eye side effects.

when to see your doctor

See your doctor if side effects don’t go away or if you have:

  • scalp or skin rash or blisters
  • difficulty breathing
  • swelling
  • nose or throat irritation
  • eye irritation or pain
  • hair patchiness or loss

You may need medical treatment for chemical burns or irritation on the skin or scalp. Your doctor or dermatologist may also recommend:

  • aloe vera gel
  • numbing creams
  • steroid cream to reduce inflammation
  • oral prednisone
  • oral or topical antihistamines to reduce itching

Let your hair air-dry if you’re experiencing symptoms after a Brazilian blowout. Avoid blow-drying or straightening your hair. Heat activates the formaldehyde in the Brazilian blowout formula and releases more chemicals.

Avoid going to salons that offer Brazilian blowouts and other keratin straightening treatments. Fumes from other customers go into the air and can cause symptoms or a reaction.

Wearing a face mask may help against fumes. However, it’s best to avoid indoor areas where hair chemicals are used.

A Brazilian blowout can be harmful to your health and hair. One of its main ingredients is a known cancer-causing chemical, formaldehyde. Brazilian blowouts and other smoothing treatments also contain other chemicals that can cause side effects and allergic reactions.

More research is needed on the long-term effects of Brazilian blowouts on stylists and those getting this treatment.

There are natural hair treatments to help you get smoother, stronger, and shinier hair. Other options for natural moisturizers that deep condition your hair include coconut oil and argan oil. Get regular trims and avoid over-shampooing your hair.

If you’re considering a hair smoothing treatment, ask your stylist to recommend one that’s formaldehyde-free. Do your research and check all ingredients. Some products may claim to be free of formaldehyde when they’re not.