Ahead, the best keratin shampoos for smoothing frizz, repairing damage, and strengthening your hair according to editor testing and stylist recommendations.

A moisturizing shampoo that’s sulfate-free is the best shampoo for keratin-treated hair, Carolyn Aronson, a professional hairstylist and CEO/founder of It’s A 10 Haircare, tells Elite Daily.

Worth checking out Moroccan Keratin Blowout Gold Series What you need to know: This high-quality Brazilian treatment kit also contains sulfate-free shampoo and conditioner. What you’ll love: It ...

Worth checking out Moroccan Keratin Blowout Gold Series What you need to know: This high-quality Brazilian treatment kit also contains sulfate-free shampoo and conditioner. What you’ll love: It ...

For the best results, your hair and scalp need to be clean before undergoing a keratin treatment. Any residue from other products may hamper the treatment’s effectiveness.

If you have thinning hair that's also brittle, bonding treatments like this shampoo can really come in handy: The formula strengthens and repairs hair while adding moisture and nourishment.

Try one of these 14 best hair thickening shampoos—tested and reviewed by Cosmo editors, dermatologists, and stylists—for fine, flat, and curly hair types.

If you have thinning hair that's also brittle, bonding treatments like this shampoo can really come in handy: The formula strengthens and repairs hair while adding moisture and nourishment.