1. Check the ingredients. You can't reverse damage, but you can restore shine and mask split ends with the right conditioner. Look for a mix of: silicones, to smooth; polyquaternium or amino acids, to strengthen; provitamins or panthenol, to moisturize; and mineral oil or petrolatum, to protect.
2. Try it dry. Removing product gunk from haggard hair is tricky, since clarifying shampoos the usual fix tend to strip away color and moisture. Instead, apply conditioner to dry roots to loosen buildup. Wet your hair, shampoo, rinse and condition again.
3. Finish up frigid. No, cold water won't "close" a hair shaft's cuticle, as you may have heard before. (Why not? Because hair isn't alive.) A cold rinse will help because it doesn't strip away as many of the conditioning agents as hot water does, says McMaster.
4. Once a week, go deep. Rejuvenate your strands with an oil treatment or with a hair mask containing a fatty alcohol (such as stearyl or cetyl alcohol) both are great at rehydrating damaged hair. (Try Neutrogena Triple Moisture Pure Strength Oil Therapy or Sellecca Shine 3-Minute Intense Moisture Treatment.)