Importance of Acidic Skin Surface pH

Importance of Low Skin Surface pH

A low skin pH (below 5) has been shown to be beneficial on several fronts [pubby id=“18489300”]. Most important findings in this area include:

  • Improved skin lipid metabolism [pubby id="7817676"]
  • Reduced permeability [pubby id="12880427"]
  • Improved residential bacterial flora [pubby id="18489300"]
  • Normal barrier repair [pubby id="12010071"]
  • Reduced inflammatory response [pubby id="19177139"]
  • Improved function of antimicrobial peptides founds in sweat [pubby id="1980979"]

Negative Consequences of a High Skin Surface pH

Elevated pH level of the skin has been shown to produce a myriad of negative effects. The most apparent of which are:

  • Reduced barrier integrity and cohesion [pubby id="12880427,19177137"]
  • Negative impact on the skin microbiota [pubby id="18489300"]
  • Delayed barrier recovery [pubby id="9617442,12880427"]
  • Increased malassezia activity and production of suspected allergens [pubby id="16867055"]

Just curious as to the use of vinegar in this regard. I read about the carbonated water and it is intriguing as I know that a vinegar solution to help treat ear infections in dogs is helpful because it “kills” the yeast/bacteria present? We have very hard water which ensures are more alkaline pH whenever I wash my hair but I have not seen any great success stories with it.


Dear Sharon,

Good question and it’s actually quite difficult to answer. Here are some potential reasons that make carbonated water more applicable then vinegar:

  • Due to it's odor, leaving vinegar on the skin may not always be an option.
  • Vinegar (especially apple cider vinegar) has a variety of different acids (acetic acid, citric acid, malic acid) at varying concentrations (acidity can differ between brands) [pubby id="15983536"]. This makes consistency more difficult and may explain some of the variation reported. Additionally, perhaps some of the differences in composition may be responsible for causing irritation when applied to a damaged skin barrier.
  • Pure carbonated water is essentially carbon dioxide and H2O at fairly controlled acidity levels, thus the chance of irritation are greatly reduced.
  • The skin itself has four main methods of buffering it's pH (lactic acid/lactate system, free amino acids, proteins, and carbon dioxide/bicarbonate system [pubby id="9145266"]) and using carbonated water is a simple way to influence one the skin's own systems.

Dear Michael,

A good answer! In fact, I remember reading that in some cases, if one used too strong a solution of vinegar, it could cause more harm than good. And of course there is the odour. I noticed you mentioned the use of baking soda in this weeks reflections and wonder if you think it would be as effective as carbonated water. I know the No Poo people advocate its use although I have not tried it. I will give the carbonated water a try though. Thank you for your thorough and clear response - it makes perfect sense. :slight_smile: