Which chemical is the main ingredient in a curl rearranger?

• A. Ammonium Thioglycolate
• B. Sodium Hypochlorite
• C. Ethanolamine
• D. Urea

Answer: (A)

Curl rearranging relies on a reducing agent that breaks the hair’s disulfide bonds so the strands can be reshaped around rods. The main ingredient used for this reducing step is ammonium thioglycolate. It donates thiol groups that cleave the disulfide bonds in keratin, turning rigid bonds into more flexible sulfyhydryl structures, which allows the hair to be molded into a new curl pattern. After processing, a neutralizer (typically hydrogen peroxide) oxidizes the hair again, reforming disulfide bonds in the new shape to lock in the curl.

Sodium hypochlorite would bleach hair and isn’t used for rearranging curls. Ethanolamine can act as a base or pH adjuster in formulations but isn’t the primary reducing agent. Urea is mainly a humectant/conditioning ingredient, not what breaks disulfide bonds in a curl rearranger.