Here's the thing. Just like at the drive-thru, there's no need to supersize it. More is not better when it comes to acne-fighting ingredients. A stronger concentration of salicylic acid (or benzoyl peroxide, for that matter) will likely just dry out your skin and isn't necessarily going to be any more effective, says Zeichner. Most OTC products typically contain between .5 percent to 2 percent; there's no need to go searching for anything higher than that.