It’s all gone a bit test tubes and lab coats at GTG HQ - pH is the topic of the day, but we’re not demanding that you get your litmus papers out and sit quietly at the back circa GCSE chemistry. We’re talking how pH affects your face, the optimal pH for skin health and why, when your skin’s pH is out of whack, dehydration, premature ageing and infection can all surface. To avoid pH imbalance and the resultant dermatological fallout, here’s the acid test as to where healthy skin sits and what tips the pH scales. First off, what does pH even mean when applied to your skin rather than science coursework?
What pH should your skin be?
"The pH scale ranges from 0 to 14. Zero indicates a very low and extremely acidic pH, whereas 14 is the highest or most alkaline pH. Water, which is neutral, sits right in the middle and has a pH of 7," explains consultant dermatologist Dr Justine Kluk. “The average pH of human skin lies between 4.7 and 5.75.” This means that skin is mildly acidic, all thanks to your ‘acid mantle’ – the protective barrier on the surface of the stratum corneum (the skin's top layer) that helps to keep moisture in and environmental aggressors out.
Preserving this acidic vibe makes for more resilient skin, as Dr Kluk explains: “Maintaining an optimal acid environment is important for skin barrier and immune function, sustaining the skin’s natural flora, inhibiting the growth of harmful bacteria and neutralising alkaline aggressors, such as harsh surfactants .”
So slight acidity is skin nirvana, but nature likes to mix things up a bit too it seems.
Why men and women’s skin pH is different
You’re not made of sugar and spice and he’s certainly not made of puppy dogs’ tails but there can legitimately be some variation in skin pH between the sexes according to GP Dr Anita Sturnham :
“The average pH of male skin is lower due to higher rate of sebum production in male skin. Men can, therefore, be slightly more prone to getting blocked pores and congestion. Men typically also have more acidic sweat than women do, which accounts for a lower pH (.05 lower) when compared to female sweat. Men usually sweat more than twice as much as women, and they are also more prone to losing more sweat when trying to regulate the same body temperature changes as women. Women are therefore thought to have a more effective sweating regulation mechanism.”
Sweat and gender aside, a number of factors can disturb your natural pH, provoking everything from eczema flare-ups to breakouts.
3 things that will sabotage your natural pH
1. The environment
“External factors such as pollution , temperature and humidity changes and exposure to harsh chemicals can all alter skin pH," says Dr Kluk.
Even living in a hard water area can shift the balance in skin pH, as the same minerals that cause limescale in your kettle can tip things too far towards the alkaline end of things, theoretically weakening the skin’s acid mantle. By all means, invest in a water softener if you live in a very hard water area, but skincare expert Paula Begoun thinks that washing your face with plain old tap water is unlikely to cause significant problems:
“Recently there have been concerns that washing with regular tap water can disrupt skin's pH, and that you should wash with sparkling water instead. The issue is based on tap water having a pH of 7 and being perceived as too high for skin’s pH. The claim is that because carbonated or sparkling water has a pH of 5.5, it’s more compatible with skin.
“Though this sounds reasonable, it's not an issue for a couple of reasons. First, most sparkling water doesn't have a pH of 5.5, and instead has a pH between 3 and 4, but even if sparkling water had a pH of 5.5, that's still higher than most people’s natural pH. Second, a neutral pH of 7 (which is what tap water has) is less disruptive of skin’s natural pH than any other pH number. Long story short, it's just fine to wash your skin tap water!”
If you’re really concerned you can check the pH of your water with your local water board - water in my London borough came in with an average pH of 7.62, which isn’t half bad for built-up Zone 2. I won’t be washing my mug with San Pellegrino anytime soon, for many reasons really (plastic, price, practicality...).
Excessive sun exposure can also inhibit the skin barrier, causing skin to become more alkaline and thus prone to damage, dryness and pigmentation.
2. Your skincare routine (and where acid exfoliators fit in)
“The pH of your skincare products plays a major role not only in their effectiveness but also in how well they interact with your skin," says Dr Kluk. Using products that are too alkaline, such as skincare containing baking soda, can cause the skin to become dry and flaky. Application of products with a very low pH, on the other hand, can also cause adverse effects, such as stinging or burning sensations.”
Either way not what you were going for. “Products such as cleansers and moisturisers should ideally be around pH 5.5 while exfoliating acids should be at pH 3.5,” explains founder and product formulator of Allies of Skin Nicolas Travis. Acidic products such as exfoliators can bolster the acid mantle and encourage healthy skin cell turnover and regeneration. However, overuse of products with a low pH can cause serious irritation too.
So how do you know where your skincare products sit on the pH scale?
Short of dipping litmus paper into every lotion and potion, Paula reassures us that most of your skincare will likely sit in the pH balanced range anyway, meaning that it has a pH of between 4 and 7, "Cosmetic chemists are aware of how the pH of skin care products impacts our skin, so they usually take formulary steps to ensure a balance.”
Paula emphasises that veering a little outside of the ‘balanced’ range shouldn’t cause issues (acidic products can be beneficial as discussed). The skin is adept at self-regulating its own pH, up to a point, however Nicolas advocates avoiding “harsh soaps with sulphates, physical scrubs and very strong chemical peels so as not to disturb the skin’s natural pH.”
To be truly ‘belt and braces’ about things, brands are increasingly listing pH on product packaging; Allies of Skin displays pH on all of its range and you’ll also find pH declared on Drunk Elephant products . Nicolas advises “If you can’t find pH of the products, reach out to the brands directly on social media for help or purchase pH strips from a pharmacy or on Amazon to test your products at home.” Intrepid but revealing.
You’ll soon be able to test your own skin pH level too; skincare brand La Roche-Posay unveiled a prototype wearable skin pH sensor and app My Skin Track pH at the CES technology in Las Vegas earlier this month. It's intended to help to improve care for people with eczema, dermatitis and chronic dryness in particular and is set to be trialled in the US later in 2019, with hopes for an eventual consumer launch in the UK. We’ll keep you posted on that, but until then, Justine notes that "dehydration, sensitivity and increased susceptibility to infection may be signs that your skin pH is out of whack.”
With age comes wisdom, but also, greater skin alkalinity. Your acid mantle naturally weakens over time, becoming less effective at keeping external assailants at bay. Skin becomes, therefore, more prone to dryness, dullness and wrinkling, as it isn’t as efficient at retaining water and repairing itself.
All is not lost due to old father time, however. Nicolas impresses that incorporating daily sunscreen (particularly of the mineral variety to reduce inflammation and sensitivity ), using a hydrating, sulfate-free cleanser and including a daily protective vitamin C and moisture binding hyaluronic acid serum in your skincare routine can help to protect and preserve the acid mantle.
For a few more pH conscious skincare picks, shop the following…