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The shampoo you choose can make a difference in the health and appearance of your hair. The pH balance of your hair and skin is about 5, or slightly acidic. Shampoos can be either acidic or alkaline; a shampoo that advertises itself as being “pH balanced” should be slightly acidic. For the healthiest hair, choose a pH-balanced shampoo.

Close the Cuticle

The outer part of your hair is called the cuticle. It is made up of overlapping scales, like the tiles or shingles on your roof. Alkaline products cause these cuticle scales to open, exposing the interior of the hair shaft, called the cortex. Plain water is alkaline enough to open the cuticle of the hair; an alkaline shampoo opens the cuticle even more. You need a slightly acidic shampoo to close the cuticle of your hair and return it to its natural state.

Prevent Damage

Moisture in the cortex of your hair shaft helps keep your hair flexible. When you use an acid-balanced shampoo to keep the cuticle closed, your hair will remain flexible. If that moisture escapes, your hair will become dry, look dull, and tend to develop split ends and other signs of damage. A pH-balanced shampoo can help prevent this kind of damage to your hair.

Keep the Color

A pH-balanced shampoo can help you keep your permanent hair color looking fresher longer. The cells that give your hair its color reside in the cortex of your hair. When you permanently color your hair, you have to open the cuticle to get to the color-containing cells. Once the color has been changed, you want to close the cuticle to seal the color inside, keeping your new color vibrant and helping it last longer.

Prevent Oiliness

Your scalp produces oil that helps keep your hair shiny and protected. This oil has an acidic pH. Most shampoos contain detergents that bond with the oil and allow it to be washed away. An improperly balanced shampoo, however, will strip away too much of your hair's natural oils. Your scalp will then overproduce oil to compensate, making your hair oily and causing it to get dirtier faster. Choose a pH-balanced shampoo to help keep your hair looking cleaner longer.