Permanent wave, a salon-administered chemical treatment, alters the structure of your hair, giving it a sustained curl or wave for months. Contrary to popular belief, perms do not damage; they restructure hair bonds, making it more voluminous with an appearance of thicker locks.
This hair treatment has not changed much since the 1900s, when German hairdresser Karl Nessler first experimented with ammonium thioglycolate to make curls last. People today get perms to turn their straight or fine hair into more textured, defined curls. Since its inception, perming has come a long way, with numerous variations to suit varying hair types and desired curl patterns.