With ageing, there is a decreased production and function of both the sweat and sebaceous glands leading to an impaired acid protection mantle, and the skin to become dry, fragile, and more likely to break. This leads to an increased risk of infection. (1)(2)
The acid protection mantle is an invisible, very fine, slightly acidic film at pH 4.5-5.5 on the surface of human skin acting as a barrier that is formed by the mix of sebum and sweat. This is a barrier that deflects outside influences such as bacteria, viruses, fungi and other potential contaminants that might penetrate the skin.
The pH of the acid protection mantle layer keeps the body’s natural flora within its limits by maintaining the pH at 4.5-5.5. If this pH level is altered for more than a short period of time, it will affect the efficiency of how the flora and microbes are kept out.
In fact, after washing, ageing skin requires more than 6 hoursto restore its acid protection mantle and normal pH while younger skin requires only 2 hours!(3)