Most dog parents probably don't realize that they should be checking their dog's shampoo bottles before bathing their dogs, especially checking the shampoo’s pH. The reason is that dogs require a shampoo that has a pH of 7.0 or greater. Dogs have alkaline skin, unlike we humans, who have acidic skin that requires a pH below 7. Human shampoos have a pH of 6.5 or below and many dog shampoos that don't specify pH on the label.
Continuous use of a product with a pH lower than 7.0 can result in dull, brittle or dry fur. A dog's skin also needs to be impervious to water and the elements, and frequent use of a wrong shampoo, can damage skin cells, so they lose their water tight barrier. This can even result in poor looking, diseased skin.