Disclosed herein is a solvent composition for one-step permanent wave and hair straightener, comprising: amino acid or a derivative thereof protein or a derivative thereof a reducing agent an alkaline agent an amino acid-based surfactant organic acid alcohol and urea. The solvent composition does not damage hair nor irritate the scalp, does not emit an odor, and can greatly improve the efficiency of curling and straightening hair and the ability to maintain the curled and straightened hair.
