Increasingly we have seen the term “pH balanced” in skin care advertising but we have never seen any brand explain what that means. So is this just another marketing term or is there something to it!?
We can’t speak for others and to be honest, are not sure what they have in mind when they talk about pH balanced. But if you care about evidence, it is something you should care about and probably more than you expect!
What is pH and what is the pH of the skin
The term pH stands for “potential of Hydrogen” and indicates how acidic or alkali a water-based solution is. A pH of 7 is neutral (like water); less than 7 is acidic and more than 7 is alkali. The average skin pH is 4.9 (acidic!) and most of us have skin with a pH that is between 4.1 and 5.8. Measuring skin pH isn’t easy. Because it is not a liquid you can’t just use litmus paper or electrodes (dipped in the solution). Scientists used to think that the skin pH was 5.5 on average, but with improved measuring technologies that has been revised down over the last number of years.
Skin pH varies by: Ethnicity (darker skin = lower pH), Age (older = higher pH (and also newborns)), Sweat (more = higher pH), Gender (women = higher pH) and Occlusion (occlusive dressings = higher pH). Genetics, medications, skincare and cleansers are also some of the factors which influence it.
Why does it need to be low?
While the pH of the surface of the skin is just under 5, the pH of the Dermis (the inner layer of the skin) is approximately 7. That sharp drop in pH is important in the process which allows the surface of the skin to regenerate and maintain its function as a barrier. That barrier helps keep moisture in, and protects us from both physical and microbial harm.
What happens if the skin pH is raised?
There are a number of common skin conditions associated with increased skin pH including Acne, Rosacea and Eczema. In addition, skin barrier repair is compromised when the pH is higher, meaning that the skin is more prone to dryness, cracking, itchiness and sensitivity and is slower to heal if the pH is raised. As for how much of an increase in pH we are talking about, a 2017 study found that people with acne had, on average, a skin pH that was 1.3 units higher than non-acne patients. Though a number of common skin conditions are associated with relatively small increases in pH (0.2 units in Eczema and 0.3 units in Psoriasis and skin that is dry and sensitive).
Why are soaps “bad” and why are you even talking about them here?
A soap is a cleaning agent which is technically the salt of a fatty acid. The main reason that soaps are “bad” is that they have a high pH (between 8 and 10). While healthy skin can usually adjust its pH back down within a few hours of washing, frequent hand washing with soaps or using soaps on skin with a compromised barrier can disrupt the skin barrier and result in some of the unpleasant consequences mentioned.
What pH should you look for?
The evidence here is a little thinner. While there are some studies that look at the impact of using different pH products for different conditions, there is still work to be done in this area. If one had to choose– it would be a pH range of between 4 and 6.5. Increasingly the evidence is pointing to pH’s towards the lower end of that range (ie. Between 4 and 5.5).
For aging skin, a pH of 4 has been shown to help moisturisation and regeneration of the skin barrier function. A pH of 4 has been shown to be beneficial for the treatment of mild acne. For normal skin, cleansers with a pH between 4 and 5 have been shown to be beneficial. Lastly, a pH of 5.5 is helpful in assisting with the healing of wounds.
Some factors that dictate a product’s pH
Some products have their pH dictated by other factors. Vitamin C (L-Ascorbic Acid) for example needs a pH of less than 3.5 to remain stable and penetrate the skin. Alpha Hydroxy acids (Glycolic and Lactic acid) drop the pH of a product and using concentrations which have been shown to be effective (3% and higher) will usually drop the formulation below a pH of 4. While that might be fine for most people, those with sensitive skin may find low pH products irritating.
So what does “pH balanced” mean!?
Well to go back to what we said at the start it’s hard to know what other brands mean. However, if “pH balanced” means using the pH of the skin ie. a pH of 5 (or 5.5 using the 1980’s estimates of average skin pH), then according to the evidence that’s OK… Unless one is looking to manage a skin condition like Rosacea or Acne or just looking at an anti-aging regime, in which case a lower pH –between 4 and 5 looks better suited.