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

The typical pH level of the hair and skin is around 4.5-5.5, making them slightly acidic. An acidic pH helps to maintain the hair cuticle in a closed and protected state, reducing frizz and maintaining shine. On the other hand, an alkaline pH can cause the hair cuticle to swell and lift, leading to damage, dryness, and frizz.