The process can take up to eight hours the first time (depending on length and thickness); touch-ups require three to four hours. For three days after the treatment, you can't get your hair wet or do anything kink inducing (like wear a ponytail), and while your hair will now be sleek and shiny (even after air-drying), you're left with one styling option: bone-straight. Even curling irons or hot rollers won't restore volume or wave. Cost: $500 to $1,500. It is far safer than Brazilian straightening but costs double.