Understanding skin – Skin’s pH

Skin is the ultimate multi-tasker, performing several essential roles for our overall wellbeing.

The most important role it plays is as a protective barrier between our bodies and the outside world, and skin’s pH is one of its key protective mechanisms. The pH of our skin is constantly challenged by external aggressors such as pollution, temperature changes and harsh chemicals. Superior skincare products help to maintain skin’s optimal pH and support and restore its natural defenses. This makes it more resilient, less sensitive and better able to carry out its vital work of protecting us. 

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. Read more in skin structure.

Skin’s pH varies slightly according to both gender and where it is on the body. It also fluctuates at different life stages.

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.

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.

The external factors that stress skin include:

• Changes in temperature and humidity
• Dirt and pollution
• Washing too frequently
• Alkaline 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.

Read more in factors that influence 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 6.5 and 5.5 as its protective acid mantle is not yet fully formed. Read more in baby and children’s skin. As hormones change later in life (for example during puberty, pregnancy and the menopause), the pH of skin can also change. Read more in skin in different ages.

We 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.  Read more in a daily skincare routine for the face and a routine for the body.

The Eucerin pH5 range – which includes body lotions, creams and cleansers - has been specially formulated to restores skin’s natural defenses and make it more resilient and less sensitive. The unique pH Balance System with Citrate Buffer helps to restore skin’s optimal pH. In the cleansers, it combines with extra mild surfactants to prevent skin from drying out. In the care products, it combines with Dexpanthenol, known for its regenerative properties, to restore skin’s natural pH, make it more resilient and less sensitive, and support long-lasting moisturisation.

All products in the range are clinically and dermatologically proven to be ideal for daily use on dry sensitive and allergy-prone skin. 

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:

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. Read more in sweating.

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.