What is pH in the human body
The skin is the largest organ of the human body and performs multiple functions, including protecting us from external agents, regulating body temperature, and participating in sensory perception. One of the less known but crucial aspects for its health is the pH of its surface. For a long time, it has been assumed that the skin's pH ranges between 5.0 and 6.0; however, recent research has shown that the natural pH of the skin is on average 4.7, meaning it is more acidic than previously believed.
This acidic balance plays a fundamental role in the skin's barrier function, hydration, and the regulation of cutaneous microflora. Below, we will explore the importance of skin pH, how factors such as water and hygiene products can alter it, and why maintaining it in its natural state is key to healthy skin.
What is pH and why is it important for the skin?
pH is a scale that measures the acidity or alkalinity of a substance on a range from 0 to 14. A pH of 7 is considered neutral, values below 7 are acidic, and above 7 are alkaline. In the case of skin, its acidic pH is known as the "acid mantle," a protective layer that helps to:
- Maintain the integrity of the skin barrier
- Control the proliferation of bacteria and fungi
- Promote hydration and prevent excessive flaking
- Support cell renewal and proper enzymatic function
The Natural pH of the Skin is Below 5.0
A study conducted on 330 people from different countries showed that, by avoiding contact with water and cosmetic products for 24 hours, skin pH decreased from an initial average of 5.12 to 4.93. This suggests that the "natural" pH value of the skin is on average 4.7, which challenges the common belief that the optimal skin pH is between 5.0 and 6.0.
This finding is important because skin with a pH below 5.0 shows better conditions in terms of hydration, less flaking, and a stronger skin barrier compared to skin with a pH above 5.0.
How Water and Hygiene Products Alter Skin pH
Many factors can affect skin pH, from the use of cosmetic products to the quality of the water we shower with. For example:
- Tap water: In Europe, drinking water usually has a pH of approximately 8.0. Washing with water alone can raise the skin's pH for several hours before it returns to its natural acidic state.
- Alkaline soaps: Many bar soaps have a pH between 9 and 10, which alters the skin's acidity and can damage it in the long term.
- Shower gels and facial cleansers: Some have a pH closer to that of the skin (between 5.0 and 6.0), which minimizes the alteration of the acid balance, but can still affect the skin barrier.
The Relationship Between Skin pH and Cutaneous Microflora
The skin hosts a community of microorganisms known as the skin microbiota. This microbiota includes beneficial bacteria such as Staphylococcus epidermidis, which helps protect the skin from harmful pathogens like Staphylococcus aureus.
Studies have shown that S. epidermidis grows better in an acidic environment (pH 4.7) in the presence of lactic acid, while S. aureus is inhibited under these conditions. This means that maintaining the skin's acidic pH helps preserve the protective bacterial flora and prevent infections.
How to Maintain Natural Skin pH
Since the skin self-regulates, the ideal is to avoid altering its natural pH as much as possible. Some recommendations include:
- Using cleansers with a pH close to 4.7 to minimize impact on the skin.
- Avoiding frequent use of alkaline soaps, especially on sensitive skin.
- Avoiding excessive washing with tap water if it is very alkaline.
- Using moisturizing creams and products with balanced pH.
Why Not Use Baking Soda or Magnesium Hydroxide in Armpits?
You might wonder why Maxalli does not include baking soda or magnesium in its deodorants, even though in recent years, baking soda and magnesium hydroxide have gained popularity as natural deodorants. This is because their use in the armpits can be harmful.
Baking soda has a pH of around 9, making it highly alkaline. When applied to the skin, it can alter the natural pH of the armpit, affecting the protective microbiota and causing irritation, dryness, and sensitivity. Many people have experienced dermatitis and skin darkening due to prolonged use.
Magnesium hydroxide, with a pH close to 10, is even more alkaline than baking soda. Although it can neutralize odors, it can also damage the skin barrier, increasing susceptibility to infections and altering the skin's bacterial balance.
If you are looking for a natural alternative, it is best to opt for natural deodorants formulated with gentle, pH-balanced ingredients that respect skin health.
Conclusion
Skin pH plays a key role in its health and protection. Maintaining an acidic pH around 4.7 is essential for preserving the skin barrier, maintaining hydration, and promoting microbial balance. Factors such as the use of alkaline soaps, deodorants, and cosmetics can alter this balance and compromise skin health. Therefore, choosing pH-balanced products and avoiding substances such as baking soda and magnesium hydroxide in the armpits is crucial for maintaining healthy and protected skin.
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