Olaplex No. 4 Bond Maintenance Shampoo, available on Amazon and
Sephora, $28
Olaplex hit fast fame in the beauty community with its three-step Hair Repair System that claims to use a patented active ingredient to repair broken strands right at the molecular level. Its shampoo — free of parabens, sulfates, and phthalates — works to repair and protect hair from everyday stresses. It's also color-safe, like many sulfate-free shampoos.
However, if you're here for post-keratin treatment options, it may not be worth the high price: Olaplex notes that since said treatments seal or laminate the hair, you'll need to wait two to three weeks before Olaplex can be effective.