Some cosmetic products claim they “restore the pH of our skin” … and that sounds great, and also very scientific, doesn’t it? Maybe you didn’t even know your skin had a pH; maybe you lived in blissful ignorance, not knowing that your pH could get out of balance… So before you start to feel like your day has been ruined, let us briefly explain what pH is.

The term ‘pH’ refers to an attribute of fluids – it’s a way to measure how acidic or alkaline the fluid might be (note: if lemons are naturally acidic, then bitter lemons are alkaline). So there we encounter the first problem: can we consider our skin to be a liquid? Well, obviously it isn’t. But things aren’t always what they seem…

pH of the skin

Inside cells, there is liquid substance, but the pH of this liquid is kept constant and is not influenced by external / environmental factors. When we’re talking about the pH of our skin, we are in fact talking about the pH of an ultra-thin moist film barrier on top of our skin, a mixture of sweat and sebum. This is commonly known as the “acid mantle” – and it has a pH between 4 and 5.5, which means it is very mildly acidic. In this moist environment, some beneficial bacteria feel at home. The pH of the skin can change slightly depending on the amount and quality of our sweat. This has everything to do with what (and how much) we drink and eat, if we do any sports or other physical activities, and if we’re taking any medicine. A ketogenic diet with a high fat & protein intake can make your sweat more acidic, for example.

Sometimes ‘experts’ claim that our skin has become more acidic over the past 60 years due to consistently eating low quality food. But since the pH value can differ from moment to moment, there is really no way to tell if someone’s general pH level has changed over longer periods of time. If we were to believe these theories, then we might get tricked into thinking there is something wrong with our skin… which might make us buy products to help us fix this (non-)issue.

What damages the acid mantle?

Our skin and its pH level do get affected short-term by using certain cosmetic products – especially soaps and bath foams. These are made of highly alkaline substances that work to eradicate our fatty sebum layer – a process you can compare to cleaning your stove with hardcore kitchen cleaner. Removing this fatty layer can “feel good” because it gives us the impression we are clean. But in fact, we are removing a very important part of our natural protection against disease: fats. This can be noticed by a small rise in the pH of our skin.

Cleaning our skin actually isn’t the best of ideas, as it not only removes fats but also our natural skin flora (good bacteria). These bacteria help to stabilize the pH of the skin, since they produce small amounts of lactic acid.
Alkaline products are to blame, but the point is that these so-called “protective” acidic or “pH neutral” cosmetic products aren’t much better. They also contain detergents that eventually dissolve the sebum. All such cleansing products remove some if not all of that protective barrier, and that makes our skin more vulnerable to adverse reactions to creams, for example, which may contain ingredients that can trigger allergies in people who are already prone to develop them. So instead of helping ourselves, we are rather creating new problems as a consequence of our cleanliness.

***Disclaimer***
That the number of allergies among the population is rising has very complex reasoning to it, involving both our general food intake and our immune system. Neither alkaline nor acidic cosmetic products are specifically to blame for this.

What would I suggest?

In my opinion… the most skin-friendly way to clean would be by rinsing your skin with purified water from a beautiful mountain lake – the way our primal ancestors did ♥ But that wouldn’t remove leftover makeup, would it? So your second best bet might be a pH neutral cleanser, so long as it doesn’t contain any alcohol or strong detergents. But products “restoring our pH” … that’s just a marketing trick, like ‘greenwashing’. They simply don’t exist. Perhaps the best thing a product can do for your skin is to affect your natural pH as little as possible.

Sources:
1. Natural skin surface pH is on average below 5, which is beneficial for its resident flora.
2. Why the pH of Skin and Products Are Crucially Important

If you enjoyed reading this article, you can get an update of what’s on the magazine dropped right into your e-mailbox. Sign up here for our newsletter!

Editor’s Note: This article was originally published in January 2013 and was updated in October 2019 for formatting.