GEHWOL pH value study

Do care products have to be pH-neutral? 
Study on foot care products provides new insights


The pH of the skin plays a crucial role in its health and protective function. With a natural pH of 4 to 6, the skin is slightly acidic and has a protective hydrolipidic film that maintains the pH. This hydrolipidic film consists of a natural emulsion of water and lipids and protects the skin from harmful germs and environmental pollutants. The skin barrier, especially the outermost layer of the epidermis, the horny layer, forms a first barrier against harmful substances and regulates the moisture balance. To ensure the optimal protective function, the density of the horny cells and the maintenance of the acidic pH value are crucial. The exact pH of the skin varies by body region, but a pH between 4 and 6 is considered healthy. 

However, many skin care products have different pH values. Each skin care product has a specific pH value. This results from the ingredients and the way they are formulated in the product with the aim of maximum effectiveness. However, the pH of a product is also important to keep the formulation stable and safe. However, if the product pH is outside the skin milieu, the question arises as to what influence the application of a care product has on the pH of the skin and what the consequences are for the care goal. Eduard Gerlach GmbH, the leading manufacturer of foot care products among podiatrists and in pharmacies, therefore commissioned a clinical
study* to investigate the effects of different pH values of foot care products on the hydrolipid film and skin condition. The results of this study shed new light on the importance of pH in the selection of foot care products.

The study found that the pH of the foot skin was effectively unchanged by the products tested. With pH-level neutral as well as acidic and alkaline foot care products, the pH value of the foot remained in the physiological normal range. All three test products, on the other hand, improved the skin condition and increased the moisture content of the skin. No significant differences were found between the products with different pH values. 

The study confirms the hypothesis for the field of foot care that the skin is able to compensate for pH value fluctuations due to its high buffering capacity. The pH value of a cream is therefore not the decisive indicator for its skin care properties. Rather, its ingredients and the way they are formulated in the product are decisive. "A pH skin-neutral care product should therefore at best be understood as an emulsion that does not change the natural pH value of the skin, but optimally improves its dermatological condition," explains Dr. Andreas Fitzner, responsible author of the study and head of research at foot care specialist GEHWOL. "The pH value is not a decisive criterion for the selection of a care product as long as it is a high-quality formulation.

*Fitzner A, Knuhr K, Brandt M, Bielfeldt S. Investigating the effect of the pH of foot care product formulations on pedal skin in diabetic and non-diabetic subjects. Int J Cosmet Sci. 2023 Apr 4. doi: 10.1111/ics.12861; Read here the study in the original: https://onlinelibrary.wiley.com/doi/10.1111/ics.12861


Read here the study in the original.