Acidification of the Skin and Maintenance of the Physiological Skin pH Value by Buffered Skin Care Products Formulated around pH 4

Anke Schulte To Brinke,Antje Mehlich,Claudia Doberenz,Ciska Janssens-Böcker

doi:10.4236/jcdsa.2021.111005

Abstract

Each biological system possesses a widely unrecognized buffer system to maintain acid-base balance to a specific pH. The skin pH is crucial for physiological skin function. In aged or diseased skin, pH increase is observed and may negatively affect skin health. Skin care products with a pH that is slightly more acidic than the average normal skin pH and have an adequate buffering capacity, are considered beneficial for the skin. However, the buffer capacity of these products also plays an important role. In the present study, a possible normalization or acidification of skin surface pH and influence on skin hydration and skin barrier function was assessed via application of buffered skin care products that are formulated with pH ≤ 4.5. 48 subjects aged above 50 were treated with three different skin care products (Vitamin C Spheres, Collagen Spray, and Collagen Mask) and skin surface pH, skin hydration and barrier integrity were assessed before treatment start and after 4 weeks. The results show that after 4-week treatment with Vitamin C, the skin pH is acidified. Treatment with Collagen Spray and Collagen Mask showed maintenance of a physiological skin pH. Subgroup analysis of subjects that had a higher than average skin pH at study start demonstrated that all three tested skin care products were able to acidify the skin surface. In addition, skin hydration was also increased for two of the three tested products, whereas skin barrier is not significantly changed. This demonstrates that buffered skin care products formulated to a pH ≤ 4.5 are able to acidify and maintain physiological skin pH and may contribute to a physiological skin function.

Highlights

Each biological system possesses a widely unrecognized buffer system to maintain acid-base balance to a specific pH [1]. pH is an important physiochemical factor that plays a significant role in various metabolic, molecular and cell-regulating processes
A possible normalization or acidification of skin surface pH and influence on skin hydration and skin barrier function was assessed via application of buffered skin care products that are formulated with pH ≤ 4.5. 48 subjects aged above 50 were treated with three different skin care products (Vitamin C Spheres, Collagen Spray, and Collagen Mask) and skin surface pH, skin hydration and barrier integrity were assessed before treatment start and after 4 weeks
We investigate the possible effect on skin pH, barrier function and skin hydration by application of 3 different cosmetic products that are formulated with a low pH and proper buffer capacity

Summary

Introduction

Each biological system possesses a widely unrecognized buffer system to maintain acid-base balance to a specific pH [1]. pH is an important physiochemical factor that plays a significant role in various metabolic, molecular and cell-regulating processes. Skin surface pH differs with age, gender, race, anatomical position, circadian rhythm, the amount of sebum on the skin, skin moisture and sweating [8]. Many exogenous factors such as occluded skin, exposure to skin irritants such as soaps and detergents, and skin washing affect skin pH. Application of cosmetic product affects skin pH as well, because many cosmetic products have a higher pH value than the normal natural skin pH and lead to an increased skin pH, higher than natural skin pH [9]. The use of plain tap water, in Europe with a pH value generally around 8.0, will increase skin pH up to 6 h after application before returning to its “natural” value of on average below 5.0 [10]

Methods

Results

Conclusion