People with curly or coily hair (curl types 3A through 4C) that's been weakened by chemical processing — color, bleach, perms, or relaxers — or that's prone to breakage and frizz. It suits anyone who wants a sulfate- and silicone-free cleanser and works for both professional and at-home curl routines. It's less relevant for straight or loosely wavy hair that isn't dealing with bond damage.

Where most curl shampoos work on the surface — adding slip so curls detangle more easily — Acidic Bonding Curls Shampoo is built around Redken's Curl-Bond Technology, a combination of citric acid, glycine, and urea that works with the formula's low pH to target weakened bonds inside the hair itself. Citric acid, an alpha hydroxy acid, helps rebalance hair to its naturally acidic pH and penetrates the cuticle to bind stray metal ions and reinforce bonds broken down by color services, heat styling, or everyday wear; glycine and urea round that out by supporting the hair's protein structure and lifting buildup. For curly and coily hair that's been chemically processed, that bond-level approach is the differentiator, rather than another rinse that just smooths the outside.

Apply to wet hair, massage into a lather, and rinse thoroughly. Follow with Acidic Bonding Curls Conditioner, and use the Leave-In Treatment as part of the complete three-step regimen for the fullest results. Avoid contact with eyes; rinse immediately if contact occurs.

What sets this shampoo apart is that its citric-acid-based Curl-Bond Technology targets the actual cause of curl breakage — weakened internal hair bonds — rather than just adding slip or shine on the surface, and it does so in a formula that's both sulfate- and silicone-free, so it won't strip curls or leave the buildup silicones can cause over time. The trade-off is that the fuller frizz-reduction results Redken reports are tied to using it as part of the complete three-step system rather than the shampoo alone, and as an AHA-driven formula it's made for hair, not skin — it isn't meant to be a gentle everyday cleanser for sensitive scalps.