The stratum corneum is the outermost layer of the skin, which forms a protective barrier and plays a vital role in the skin. The main functions of the stratum corneum barrier are as follows:

Waterproof function:

The stratum corneum can effectively prevent the penetration of water, both external and internal. It is like a wall, protecting the skin from the external environment and preventing water loss.

Prevent the invasion of harmful substances from outside;

The stratum corneum has the property of semi-permeable membrane, and some small molecules such as oxygen and carbon dioxide can penetrate it, but most harmful macromolecules such as bacteria and viruses cannot penetrate it, so it helps to protect the skin from pathogens.

Regulate body temperature:

The stratum corneum regulates body temperature by controlling the balance between water and temperature. When the external environment becomes cold, the cuticle will shrink to reduce water loss and heat loss; When the external environment becomes hot, the stratum corneum will relax to accommodate more water and increase heat absorption.

Protect skin from ultraviolet rays:

The stratum corneum contains a substance called "natural sunscreen", which can absorb ultraviolet rays and reduce its damage. Therefore, even if exposed to the sun for a long time in a strong sunlight environment, the skin is not easily damaged by ultraviolet rays.

Maintain skin acid-base balance:

The stratum corneum contains a substance called lactic acid, which can help maintain the acid-base balance of the skin and keep the skin in a relatively stable acid-base environment.

Participate in metabolism:

Keratinocytes in the stratum corneum can participate in metabolism and maintain skin health by absorbing and releasing nutrients.

To prevent mechanical damage:

The stratum corneum is like a protective film, which can prevent the skin from mechanical damage such as friction and impact.

Expand knowledge:

The thickness and composition of stratum corneum vary with the physiological state and environment of human body. For example, in a dry environment, the stratum corneum will become thicker to prevent the loss of water.

In a humid environment, the stratum corneum will become thinner to keep the skin moist. In addition, the composition of the stratum corneum will also change with age. With the increase of age, the moisturizing ability of the stratum corneum will gradually weaken, resulting in dry skin. Therefore, keeping the stratum corneum healthy is very important for keeping the skin healthy.