This Cadillac of at-home straighteners covers all the bases: It comes with a pretreatment shampoo and a post-treatment strengthening sprayso hair stays smoother and shinier for a full month ($235; sephora.com
"Instead of formaldehyde, this uses a more gentle skin-conditioning agent to alter the chemical composition within hair," says cosmetic chemist Ni'Kita Wilson. "It does an especially good job of reducing frizz in coarse hair."OUR VERDICT
Though applying it was messy (the keratin looked like coffee and dripped a lot), the results were worth it. When we washed the treatment out 48 hours later, our strands still had wave but looked smooth and frizz-free, even without blow-drying.