What is pH 5.5?
The pH of healthy skin
Our skin can be assigned a pH value because the hydrolipid film on the skin’s surface contains water. It was discovered about a hundred years ago that the skin is slightly acidic. Modern measuring techniques produced an average pH value of 5.5, which is due to natural acidic substances in sweat, sebum, and horny cells. The significance of the acidic nature of the skin’s surface is demonstrated in the “acid mantle”.
The Acid Mantle
The acid mantle's job is to repel harmful microorganisms and negative environmental influences and, in doing so, protect the skin from infections, irritation, allergies, and drying out. An intact acid mantle also functions as a natural deodorant, because it minimises the bacterial breakdown of sweat which causes body odour.
It is therefore vital that you don’t do anything that could damage your acid mantle. You should for example avoid cleansing your body with “normal” soap, because the soapy water will have a pH value of 8 to 12 and will destroy the acid mantle. Washing with “pH neutral” products, whose pH values of 7 differ considerably from the skin’s of 5.5, can harm the acid mantle as well though. And finally, you should steer clear of any contact with basic solutions while working.