A protein treatment is a hair care treatment that helps to strengthen and repair damaged hair. Protein treatments work by filling in any gaps or cracks in the hair shaft. This helps to make the hair stronger and more resilient to damage. Protein treatments can also help to improve the shine and softness of hair. Protein treatments are especially beneficial for people with damaged hair, including hair that has been bleached, colored, or heat-styled. They can also help to prevent future damage to hair. Protein treatments are safe for all hair types, including color-treated hair and extensions.