How does pH levels of the hair and skin and how acid pH and alkaline pH affect the hair cuticle?

The pH levels of hair and skin are slightly acidic, typically ranging from 4.5 to 5.5. An acidic pH helps to keep the hair cuticle closed and protected, resulting in stronger, more manageable hair. On the other hand, an alkaline pH can cause the hair cuticle to swell and become raised, leading to dry, frizzy, and damaged hair.