What Is Skin’s Acid Mantle?

pH is a measure of how acidic a substance is. Its value ranges from 0 to 14. 7 is neutral. Below 7 is acidic. Above 7 is alkaline.

The topmost layer of the skin is called the stratum corneum. This is the visible layer of skin. This layer is acidic. Its pH lies between 4.5 and 5.5. This layer is also called the acid mantle.

This acid mantle performs 2 important functions:

1. stops water from the deeper layers of skin from escaping into the environment (stops from escaping through the top layer)
2. acts as the first layer of defence - protects skin/body from harmful nasties in the environment (bugs, pollution)

Skin's acid mantle works like a shield.

So what is in the skin's acid mantle?

The top layer of the skin has a layer of dead cells called keratinocytes. These cells are arranged like bricks. Just like bricks are held together by cement, these cells are held together by epidermal lipids (fatty, oily substances).

Above keratinocytes we have the following:

1. Sebum. Sebum is a lipid and is secreted by sebaceous glands in the skin. Sebaceous glands are also knowns as oil glands. Lipids are fats and oils.
2. Microbiome. The microbiome is the skin's flora. There are trillions of bacteria, fungi and viruses. These are the good bugs and help the skin carry out its function.
3. Sweat. Sweat is mainly composed of water, sodium and lactic acid.

The following together make up the acid mantle:

1. Epidermal lipids (this the glue that holds keratinocytes together)
2. Sebum (lipids)
3. Sweat
4. Microbiome (good bugs)

What happens if the skin's acid mantle is weak?

The top layer has to be at the right level of acidity to perform its job. Otherwise, it becomes weak - when it becomes weak, water escapes and nasties attack the skin/body. A weak acid mantle results in the skin becoming prone to irritation, dryness and breakouts.