Can Keratin Treatments Make You Sick?

young woman with long hair( — You love that straight, glossy look that can last for months. But did you know that brazilian keratin treatments, according to various government reports and warnings, may actually be hazardous to your health?

How Brazilian Keratin Treatments Work

The Brazilian keratin treatment involves soaking the hair with a cocktail of keratin and oils to form a hard outer shell around the cuticle, which helps strands hold their new shape. The treatment works on all types of hair—even damaged or chemically treated tresses, says Dror Kraft, a stylist and treatment specialist at Pierre Michel Salon in New York City, who has been performing the service for several years.

Formaldehyde: The Toxic Chemical Culprit

The solution doesn’t alter your hair – instead, it locks in the temporary straightening results with formaldehyde—a chemical used in low levels in household cleaners, hand soaps, glue, and synthetic fabrics. “In higher concentrations formaldehyde can cause respiratory problems, skin allergies and irritation, and sometimes even cancer,” says Richard Parent, a board-certified toxicologist in Damariscotta, Maine. “And most—but not all—salon keratin treatments produce varying amounts of it,” says Wilson.