Chemical hair straightening is a process that uses chemicals to break down the protein structure of curly hair to permanently straighten it. The chemicals used in hair straightening treatments include cyclosiloxanes, formaldehyde, parabens, diethanolamine, sodium hydroxide, phthalates, triclosan, and benzophenone-3. These chemicals can cause long-term damage to hair and skin and increase the risks for other health issues, including cancer. Some of the most common ingredients used in hair straightening treatments include:

• Keratin: A protein that is naturally found in hair, skin, and nails. It helps to strengthen and protect the hair while also smoothing the cuticle.

• Formaldehyde or Formaldehyde-releasing agents: A strong chemical that can break down the bonds in the hairs structure, allowing it to be straightened. However, formaldehyde has been linked to health concerns, so many hair smoothing treatments now use formaldehyde-releasing agents that produce lower levels of formaldehyde.

• Glyoxylic Acid: A type of alpha hydroxy acid that helps to smooth the hair cuticle and reduce frizz.

• Thiourea Dioxide: A reducing agent that helps to break down the bonds in the hairs structure.

• Calcium Hydroxide: A strong alkaline ingredient that helps to open up the hair cuticle, allowing it to be straightened.

• Guanidine Carbonate: A strong alkaline ingredient that helps to break down the bonds in the hairs structure.

• Ammonium Thioglycolate: A reducing agent that helps to break down the bonds in the hairs structure.

Some hair straightening treatments claim to be formaldehyde-free, but they may still contain chemicals that become formaldehyde when they’re heated. It is important to read the labels and ask questions about the ingredients used in hair straightening treatments to avoid harmful chemicals.