The skin's pH value

The term “pH value” has been widely talked about for years now.  There is hardly anyone who hasn’t heard it or read it on shampoo bottles or tubs of cream. But how many people are actually aware of what this abbreviation stands for and what it means?

“pH” is short for the Latin term “potentia hydrogenii” and translates as “hydrogen ion concentration”.
pH values allow us to differentiate acids and bases from each other and label them according to strength. Anything that contains water also has a pH value, which can be determined using an electronic pH meter or an indicator such as litmus.


pH-value 0

Sulphuric Acid

With a pH value of approx. 0, sulphuric acid is one of the strongest acids of all. The mineral acid is highly corrosive.

pH-value 3


The juice from a lemon is highly acidic with a pH value of approx. 3.0.

pH-value 5,5


The hydrolipid film on the skin's surface has an average pH value of 5.5 and is formed form natural acidic substances in the body. It protects the skin from external influences.

pH-value 7


The middle value of pH 7 is described as neutral. Water possesses this value.

pH-value 9


The pH value of traditional soap lies between 9 and 10, which destroys the skin's natural acid mantle and dries the skin out.

pH-value 14

Sodium Hydroxide (Caustic Soda)

Caustic Soda is a highly alkaline solution and very corrosive in concentrated forms.(pH value 13.5-14)

Move the cursor over the different pH values to display some information about each one.

The acid mantle

Our skin can be assigned a pH value too, 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”.

Its job: 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. And finally, you should steer clear of any contact with basic solutions while working.