Process to simultaneously color and permanently restructure hair, wherein (a) an oxidative hair colorant is applied to the hair based on at least one developer substance and least one coupler substance, (b) the oxidative hair colorant is left on for 5 to 60 minutes, (c) the oxidative hair colorant is rinsed out of the hair, (d) an acidic intermediate treatment agent with a pH of from 2 to 6 is applied to the hair, (e) after an action period of from 1 to 10 minutes, the intermediate treatment agent is rinsed out, if necessary, and the hair is then rolled up onto curlers, (f) a keratin-reducing permanent restructuring agent is applied to the hair, (g) after an action period of from 1 to 30 minutes, the keratin-reducing agent is rinsed out, if necessary, (h) the hair is fixed with an oxidative material, (i) after an action period of from 3 to 15 minutes, the hair is rinsed with water, if necessary and then treated with an acidic rinse. The process is intended to enable better, faster, and gentler coloring of human hair, particularly natural hair, than was previously possible, as well as to maintain the color intensity of colored hair or to refresh (renew) it, and to improve the hair shine while simultaneously restructuring the hair.