The craze for pH 5.5 appears as the hottest trend these days for skin care products, but pH as a measure in electrochemical cells has been around since 1909, when it was first used to test beers at Carlsburg labs for their acid or alkaline levels.
When we say pH, which is an abbreviation for latin term ‘potentia hydrogenii’, we are referring to the concentration of hydrogen ions in a solution. As this concentration increases, pH values decrease, making the solution more acidic and vice versa.
pH generally ranges from 0-14 under controlled temperatures used in pharma industry, as one far end is not more than 1M of hydrogen ions, which results in a pH value of not more than 0. While on the other end is not more than 1M of hydroxide ions which results in a pH value of not more than 14, but that doesn’t mean it cannot go beyond this range. A good example is water, which has pH value of 7 at room temperature, but has different pH values at variant temperatures.
Now let’s understand how pH relates with our skin. Human skin has a very thin protective layer on the surface that helps to maintain its acidity level. Skin acidity helps to keep the moisture locked in and protects the trillions of bacteria that live on our skin. This protective skin layer is made up of amino & lactic acids besides sebum. Normally our skin pH values are in the acidic range of pH 4.0 to 7.0
Skin’s pH value is checked by applying a thin layer of pure water and then directly testing the pH via a pH meter or pasting a pH indicator on the skin. pH of skin is assessed by the amount of sweat and sebum on it and varies across various areas of our body. Less exposed areas tend to have higher acidity, unlike our face and hands that remain more exposed, thus becoming more alkaline. So for the same person, the pH indicator may read differently, if tested on a different part of the skin and at different times
When the skin pH balance gets disturbed, becoming either too alkaline it leads to a flaky red skin and if it becomes too acidic, we suffer from inflammatory skin conditions like eczema and acne.
Consumers today are made to believe pH 5.5 is the most suitable level for all skin types, and thus they are always keen on checking this pH balancing power on all skin care products. While there is no denying the fact that pH is relevant, what is equally important is to understand that with each skin type, the pH differs. pH requirements are not the same for everyone, just like our skin types vary, so does our pH requirements.
Typically, dry skins have a lower pH, closer to pH 4.0, whereas oily skins have a higher pH closer to 7.0. Also it’s important to know pH as a measure applies only for the outermost layer of our skin. The deeper cell growing layers of our skin are pH neutral. Similarly, newborns have relatively high pH levels all over their skin but as babies grow older, their pH levels decline. The average newborn has a skin pH of about 7, while the average adult skin pH is 5.7.
pH is also applicable on products, as various ingredients used in skin care products have their own chemical properties, and pH condition is factored in when any formulation is made, to avoid degradation of its active ingredients. As most ingredients have their own requirements of optimal conditions for best performance, experts don’t forcefully adjust the pH for all ingredients to be 5.5. They use pH adjusters to make products stable, safe & effective on shelves, irrespective of external conditions.
Now let’s understand why pH of products is key for end users. For example if the pH of baby body cleanser or body moisturizer is high, it can dry & dehydrate the skin, and if a child already has extremely sensitive skin or some inflammatory skin condition, such as eczema, it will be safer to pick cleansers and moisturizers that range from pH 4.6 to 5.5 to avoid further skin dryness.
Often product ingredients like oils, fragrances, drying alcohols, and harsh cleansing agents can cause inflammation and damage the thin protective layer of the skin. Worth highlighting is half the bias, when cleansers are judged by just their pH, ignoring what may be equally important, such as the surfactants (or cleansing agents), texture and other ingredients that add to the quality of cleansers, making them better than others.
While one pH may not fit all, it’s wiser to make the skin care products selection based on the natural state of the skin. Compared to adults, children usually have very healthy skin, and it’s important for us to keep it protected from damaging environmental exposure as much possible, with use of products that aid in keeping their outer protective skin layer undamaged.
