SALON KERATIN TREATMENTS are unrivaled in their ability to smooth and straighten hair, but they can cost upward of $300. “At-home [keratin] treatments are not as powerful, as they coat the hair rather than altering the structure of the hair, so they generally only last a week at most,” says celebrity hairstylist Andrew Fitzsimons. But if you're more interested in making things easier on your wallet, these are the best at-home keratin treatments for smoother, softer hair.