skin: an owners manual #1
The acid mantle is a thin barrier layer, the interface between you and the outside world. A very thin, slightly acidic film that protects you from bacteria, viruses and other contaminants.
It might not sound pretty, but a healthy acid mantle is your body's first-line of defense. Breakdowns in the acid mantle cause dry, sensitive, irritated, cracked skin which is susceptible to infections.The layer is made up of "friendly secretions" sebum, perspiration and lactic acid.
The pH of healthy skin is between 4.5 and 5.5, which is slightly acidic: water is 7.0, or neutral, and lemon juice 2.0 which is pretty darned acidic.
In healthy, balanced skin, there is also a chemical that helps dead skin cells to slough. Imbalances are caused by diet and environment, conditions like eczema, and well-meaning (but off kilter) skin care.
It turns out, all skin is sensitive skin; imbalances cause reactivity which results in overly dry, or overly oily skin. Returning to balanced skin requires a nuanced touch, and time - - facials, massage, yoga, and gentle care.
It may be helpful to think of the skin, not as a type (oily, dry, combination), but as a state. The state the skin is at this time, and treat accordingly - being gentle to avoid breakdowns in the acid mantle.