It is the first physical barrier of our body. It provides mechanical protection by its elasticity and resistance, a thermoregulatory function, it contains tactile and pain receptors and provides chemical protection against bacteria, microbes and toxic products through secretions (secretions such as sweat which also a purifying role).
It is absorbent: any substance applied to the skin passes the skin barrier and is found in the blood 20 minutes after application. What is applied penetrates almost directly into the blood and quickly reaches the vital organs. Hence the importance of applying natural products that will not damage the skin, the hair or the immune system.