Shampoos for Oily or Dry Hair continued...
That can result from using shampoos with a strong detergent, chemically processing hair (such as getting a perm, relaxer, or coloring it), and using heat to style it. Even wind and other kinds of friction can damage the cuticle, Hanjani Galant says. "The more of this damage it sustains, the more dry and lusterless it becomes."
"When this damage happens, there is a loss of the keratin protein that makes up the hair, and we try to replace this using shampoos that contain keratin, as well as other keratin treatments," Acord says.
But there's only so much a shampoo can do to repair that damage, especially the kind that results from perms and coloring. "That process starts by opening the cuticle to allow the chemical in to the central part of the hair, and then another part of the process closes the cuticle," Hanjani Galant says. "But every time you do that, the 'shingles' don't line up exactly the way they were, and the damage keeps building."
Straightening and Smoothing Shampoos
Shampoos that claim that they'll straighten or smooth your hair generally have a coating ingredient in them.
"It's usually silicones...[or] oils," Acord says. "They will aid in coating the hair, and allowing hot tools to straighten and/or smooth it out."
What about the shampoos that claim to give your hair more volume? Most of them are formulated to open the hair's cuticle, making it thicker, Acord says. "But that, too, can damage the hair, and it will also remove color as well as reversing perms and relaxers."
No shampoo is going to make hair lighter and fluffier, O'Brien says. "Your best bet for more volume is a shampoo that has a nice, lightweight conditioning agent that rinses off really well."
But most people don't pick conditioners that do that. "The consumer wants something we in the industry call 'slip' -- that slippery, smooth feel you get from your hair after you rinse the conditioner out," O'Brien says. "But feeling 'slip' doesn't mean it's helping your hair. In fact, it means the conditioner is staying on your hair, and you don't want it to stay."