The treatment promises to reduce frizz and deliver smoother and stronger hair that lasts for months. The brand says that it has never used formaldehyde in any of its products. Instead, it enlists a proprietary formulation made up of keratin (the protein that makes up your hair), glyoxyloyl carbocysteine (which reduces static) botanical extracts, vitamins, and sericin, which is a component of silk. “In silk, sericin acts as cement between fibrous filaments,” which maintain the structure of cells, explains Kathy Combs, vice president of global education for Cezanne Professional Products. “It acts similarly when Cezanne is applied to the hair, bonding to natural keratin and cementing itself between strands of keratin proteins — sealing in moisture, adding luster, protecting bonds, and locking hair into a smoother, straighter form,” says Combs. This formulation is intended to help replace and repair lost and damaged protein mass by using a low-pH system to open the cuticle and infuse the cortex with that blend. Then, when heat is applied, it causes the cuticle to close and the ingredients are “locked” into the hair, smoothing the hair from the inside out.