The U.S. Food and Drug Administration (FDA) plans to propose a ban on hair-straightening chemicals linked to health risks, according to CNN, which lists the actions the executive agency plans to issue.



The agency plans to develop a proposed rule that would specifically ban hair straightening products that contain formaldehyde and other formaldehyde-releasing chemicals, such as methylene or ethylene glycol.



Hair is mostly made up of keratin (more than 80%), a group of proteins with a large number of disulfide bonds. The outermost fur scale is protective and has numerous scale-like structures on it.



How does hair change shape? The disulfide bond is what makes our hair bend or straighten.


In simple terms, there are three steps: opening the fur scale to allow the agent to enter the fur, disconnecting the disulfide bond and styling the hair, and reconnecting the disulfide bond to fix the hair styling. Whatever agent is used, the essence is a rearrangement of disulfide bonds.



So, what ingredients are added to these perms and hair dyes that play a role?



The active ingredient in perms, whether it's curling or straightening hair, is a chemical called ammonium thioglycolate.


Ammonium thioglycolate is a colorless, transparent liquid with a strong ammonia odor, but it can permanently change the structure of hair.



The perm containing thioglycolate will destroy the disulfide bond of the hair protein. Tony then uses a curling iron to style the hair or a straightening board to straighten the hair, making the hair permanently curly or straight.