Formulating at pH 4-5: How Lower pH Benefits the Skin and Formulations

Dec 1, 2008 | Contact Author | By: Johann W. Wiechers, PhD, JW Solutions
Your message has been sent.
(click to close)
Contact the Author
Save
This item has been saved to your library.
View My Library
(click to close)
Save to My Library
Title: Formulating at pH 4-5: How Lower pH Benefits the Skin and Formulations
skin biochemistryx barrier functionx pHx preservationx penetrationx formulation sciencex chemical stabilityx
  • Article
  • Media
  • Keywords/Abstract

Keywords: skin biochemistry | barrier function | pH | preservation | penetration | formulation science | chemical stability

Abstract: Most skin products are formulated around pH 6 but the latest research in skin biology suggests the skin is significantly more acidic—around 4.7. Here, the author shows how formulating for this natural pH can enhance the skin penetration of actives, reduce the amount of preservatives required, and increase chemical stability.

Excerpt Only This is a shortened version or summary of the article you requested. To view the complete article, please log in or create an account. Registration is Free!

Ever since Johnson & Johnson introduced its “pH 5.5” product range, which is in fact formulated at a pH of 5.5, consumers have come to know that the pH of the skin is 5.5—or at least they believe it should be. However, reports in the literature suggest that the pH of skin is lower, more on the order of 4.7. This review discusses the meaning of pH and how it is measured on human skin; which processes regulate the natural skin surface pH; and what processes are regulated by natural skin pH. It then describes the importance of this acidic pH for normal skin homeostasis, what factors cause deviations from natural skin pH, and finally discusses the implications of a pH lower than the generally assumed level of 5.5 for the formulator of cosmetic products.

 

pH, Natural Skin pH and How to Measure It 
Most individuals will have come across pH for the first time during their secondary education, learning that it was the -10log of the concentration of hydrogen ions in an aqueous solution. Water was described as a molecule that could dissociate into H+ ions and OH- ions according to the reaction:

Excerpt Only This is a shortened version or summary of the article you requested. To view the complete article, please log in or create an account. Registration is Free!

 

Close

Figure 1. a) Hypothetical

 Figure 1. a) Hypothetical

Figure 2. In vivo skin

 Figure 2. In vivo skin

Figure 3. Schematic representation

 Figure 3. Schematic representation

Figure 4. Skin surface pH

Figure 4. Skin surface pH 

Figure 5. Effect of single treatments

 Figure 5. Effect of single treatments

Figure 6. Frequency distribution

Figure 6. Frequency distribution 

Figure 7. Preservative action

Figure 7. Preservative action 

Figure 8. The effect of pH

Figure 8. The effect of pH 

Wiechers: Formulating at pH 4–5 Footnotes

a The Skin pH-Meter PH 905 is a device of of Courage & Khazaka, Cologne, Germany.
b SymDiol 68 (INCI: 1,2-hexandiol (and) 1,2-octanediol) is a product of Symrise.

b SymWhite 377 (INCI: Phenylethyl Resorcinol) is a product of Symrise, Holzminden, Germany. 

Next image >