The hydrolipidic film is a thin layer of oil and water that coats the surface of the skin. It is made up of sebum (oil) produced by the sebaceous glands, sweat produced by the sweat glands, and dead skin cells. The hydrolipidic film helps to protect the skin from environmental factors, such as wind, cold, and UV radiation. It plays a vital role in maintaining skin health, hydration, and suppleness.
The hydrolipidic film, also known as the acid mantle, serves as the skin’s primary protective and defensive barrier. With a pH range of 4.5 to 6.5, averaging around 5.5, the acid mantle creates an inhospitable environment for many microorganisms, preventing them from penetrating or colonizing the skin. The acidic nature of the hydrolipidic film can be attributed to the secretion of lactic acid by sweat glands.
Some of the functions of the hydrolipidic film:
- Protection: The hydrolipidic film acts as a barrier against external aggressors, such as pollutants, bacteria, and irritants. It helps to prevent the penetration of harmful substances and microbes into the skin.
- Hydration: The hydrolipidic film helps to lock in moisture and prevent excessive water loss through the skin, known as transepidermal water loss (TEWL). This function is vital for maintaining skin hydration and suppleness.
- pH regulation: The hydrolipidic film contributes to the skin’s slightly acidic pH (approximately 4.5-5.5), which is essential for maintaining a healthy skin barrier and preventing the growth of harmful bacteria.
Preserving the integrity and consistency of the skin’s hydrolipidic layer is essential for overall skin health and bodily safety. Nonetheless, certain factors can negatively impact the hydrolipidic layer, including the following:
- Harsh soaps and detergents
- Hot water
- Frequent handwashing
- Air conditioning
- Medications
- Medical conditions, such as eczema and psoriasis
The majority of professional skincare products are formulated to protect and maintain the skin’s hydrolipidic layer without causing damage. These products are designed with pH levels that correspond to the acid mantle’s natural pH range. However, many DIY skincare products created at home or by inexperienced individuals may not be properly pH-balanced, which can potentially harm the skin over time.