What is skin’s pH?

Skin's protective mantle is mildly acidic
The optimal pH value of skin on most of our face and body lies between 4.7 and 5.75. A pH of 7 (that of pure water) is considered neutral. Anything below that is acidic and above it alkaline, so skin’s natural pH is mildly acidic. This mildly acidic pH is created by skin’s acid mantle, the water part of the hydrolipid film that protects the external layers of skin. Skin’s pH varies slightly according to both gender and where it is on the body. It also fluctuates at different life stages.

Why does skin’s pH matter?
When skin‘s pH is compromised, it is prone to infection. The acid mantle helps to keep skin healthy. Skin’s pH plays an important role in skin condition. The acid mantle is key to skin’s protective barrier. It neutralises alkaline-based aggressors (such as harsh surfactants), inhibits the growth of bacteria and restores and maintains the optimal acid environment in which skin’s natural flora can thrive. If skin’s pH rises into the alkaline range, its natural balance is disturbed. Essential epidermal lipids cannot be synthesised and skin loses water and dries out. In this condition, the outer layer of skin (or epidermis) is no longer able to work as a protective barrier. When skin’s barrier function is compromised it is less resilient and more sensitive to environmental triggers.
It can become dry, sensitive or hypersensitive, and is susceptible to infections, diseases such as Atopic Dermatitis and conditions such as Rosacea (Acne).
What can affect skin’s pH?
There are many external and internal factors that may have an impact on skin’s pH. Skin’s location on the body can also affect its pH and certain skin conditions, such as Atopic Dermatitis, alter the pH of skin.
External factors
Harsh chemicals affect skin‘s natural pH. Frequent washing, in water that is too hot, can stress skin.
The external factors that stress skin include:
Changes in temperature and humidity
Dirt and pollution
Washing too frequently
Fat base cosmetics
Chemicals
Chemicals with an alkaline pH are particularly detrimental to skin pH. They overtax skin’s natural neutralising capability, damage cell structure and impair the skin’s protective barrier. Certain medicines (e.g. chemotherapy, diuretics and antibiotics) and medical procedures (e.g. radiotherapy and dialysis) can also affect skin’s natural defence, alter its pH and impair its protective barrier.
Internal factors
Products that support skin‘s natural pH help to keep skin in good condition. The protective acid mantle takes time to form, so newborn babies have particularly sensitive skin. Our genetics, biological age and hormones can also affect skin’s pH. The pH of male and female skin differs slightly. The average pH of male skin is lower due to higher rate of sebum production in male skin.
During the first few weeks of life, a baby’s skin has a higher pH of between 7.4 as its protective acid mantle is not yet fully formed. As hormones change later in life (for example during puberty, pregnancy and the menopause), the pH of skin can also change.
You can help to support skin’s optimum pH with healthy lifestyle choices, a regular skincare routine and by using products that respect skin’s natural pH and maintain its protective barrier. It is also advisable to treat certain areas of the body (such as the hands, armpits and intimate area) with products that are formulated to respect their natural pH. 
Microbiome-S (pH5) is specifically designed to restore the skin's natural defenses (skin microbiome), increase skin elasticity and reduce sensitivity.
Clinically and dermatologically proven to be ideal for daily use on dry, sensitive and breakout prone skin.
How does skin’s pH differ across the body?
Skin structure, and its pH, differs slightly according to where it is on our bodies. While most skin on the face and body has a pH of between 4.7 and 5.75, there are some notable differences:
When skin has a lower acidity, it is susceptible to infection. Hands need special care as their protective acid mantle is under stress.
Hands
Hands work hard and are constantly exposed to external forces. As a result, the pH of skin on the hands is stressed. Its protective acid mantle may be weakened and skin is more susceptible to drying out and irritation.
Armpits
Armpit skin can go for long periods without light or air, conditions that help bacteria to grow. Armpit skin is also frequently subjected to the harsh chemicals in some anti-perspirants and/or hair removal products. For these reasons, it has a pH closer to 6.5. This significant reduction in acidity makes it further susceptible to bacteria. It is the breakdown of this bacteria that can lead to unpleasant body odour.
The genital area
Like armpit skin, the skin in the genital area has a pH of 6.5. This reduced acidity makes it prone to bacterial infections.
Why do Microbioserum preparations have a pH of 7.2?
1. Not all Microbioserum preparations have a pH of 7.2. Microbioserum produces preparations with a pH of 5.
2. The lower layers of the epidermis (skin) have a physiological pH of 7.4.
3. pH 7.2 is optimal for bioactive substances to pass through the transdermal barrier.
4. Most bioactive substances, including enzymes, are activated at pH 7 and above.
How does pH affect skin?
pH has a huge impact on your skin’s barrier function, moisture retention, and microorganism environment. If your skin's pH is too alkaline - think nine and above - the lipid layer of skin can be compromised, resulting in dryness and irritation. Keeping pH at its ideal level also prevents overgrowth of acne-causing bacteria, propionibacterium acne.
How can I test my skin's pH?
The pH of the skin can be checked using pH tests (litmus plates). One way you can tell if your acid mantle is being stripped (and your pH balance is off) is how it feels after cleansing - it shouldn’t feel tight or dry.
How else would I know if my skin pH balance is off?
Some signs that skin's pH is out of balance can include acne, dryness, and conditions like psoriasis. Alkaline skin symptoms include dryness and accelerated aging, like an increase in fine lines and wrinkles. If you have a decrease in pH and it becomes more acidic, skin can become inflamed.
What's the best way to restore the pH balance of my skin?
Healthy habits are the key to maintaining a good skin pH. Choose a gentle skincare regimen, avoid harsh cleansers, wash no more than twice daily, and consult a dermatologist to recommend products for your skin type. Opt for non-soap cleansers, as they are less drying. Avoid over exfoliating with alpha and beta hydroxy acids and alcohol-based toners.
Are there natural ways to restore skin's pH balance?
If you're looking for natural ways to restore your skin's pH balance, make sure to give skin the nutrients and minerals it needs by including fruits and vegetables (especially dark leafy greens and berries) in your diet to boost antioxidant levels, and hydrate with at least eight glasses of water per day.
How can I tell the pH of my skincare products?
Check the packaging. Many skincare products don’t list pH levels but may say 'pH balanced'. Most have an acidic pH, unless the product is formulated to treat a specific medical condition, such as psoriasis, where the pH products target an alkaline pH level. If you are unsure about the pH of a product and can't find it on the label or the brand's website, consult a dermatologist to find out if that product is right for your skin.