Updated: Oct 1, 2021
The acid mantle is a very fine film on the surface of the skin. It acts as a barrier to protect the skin from bacteria, environmental pollutants, and moisture loss. The acid mantle is made up of sebum (the skins natural oil), sweat, and dead skin cells.
To understand the acid mantle we need to have a basic understanding of pH. pH is the measure of hydrogen ions, it measures a solution for acidity or alkalinity on a scale of 0 to 14. On this scale 7 is neutral, below 7 is acidic and above 7 is alkaline. Not all liquids have a pH, only those with water.
The ideal pH of the acid mantle is 4.5-5.5 meaning that the “acid” mantle is slightly acidic to prevent harmful bacteria and environmental pollutants, which are naturally alkaline, from penetrating and damaging the skin. If the skin’s pH rises closer to neutral (7), it becomes less able to kill bacteria, leading to bad bacteria multiplying rapidly and causing dehydration, acne, sensitivity, and a whole host of other skin issues.
Unfortunately it’s pretty easy to damage the acid mantle. Cleansers and products that have a high pH will change the pH of your skin for a short time (skin will usually balance itself within about 30 minutes), but continued use can disrupt the mantle permanently. High pH products can dilate the follicles allowing bacteria and toxins to enter.
If you wash your face and it feels slightly tight and “squeaky” clean, you have removed the acid mantle. When your skin is feeling soft again, the acid mantle has rebuilt itself. Keep in mind bar soaps can have a pH of up to 9 and 10, therefore continued use of bar soap can permanently damage the acid mantle.
The regular use of acids/peels, extreme health and cold, sun, air conditioning, pollution, free radicals, over exfoliating and skincare products that are too acidic or alkaline can all damage the mantle.
The factors that affect the skin barrier are:
Aging – as we age skin barrier function becomes weaker. Skin tends to be quite dry, there is a lot of moisture loss
Water has a pH of about 6 – 8.5 which makes it alkaline. Washing too much can cause a loss of NMF’s in the skin as well as damaging the barrier
UVA/UVB damage – normally neutralized by skin’s natural antioxidant defense system however prolonged exposure can weaken the skins natural defense system
Chemical influences such as detergents and perfumes can alter skin’s natural pH levels and damage the barrier causing the skin to become dry and sensitive
Temperature/humidity - cold weather can cause dry skin, low humidity can cause dehydration and skin sensitivity, and humid/hot weather can increase sebum production leading skin to be moist and shiny and may trigger skin conditions such as rosacea.
Washing with harsh products that have a high pH and make your skin feel “squeaky” clean.
Signs of a damaged skin barrier
Cracked skin sometimes even bleeding
The good news is the acid mantle can be repaired, although it will take time.
Using products with a pH as close to 5.5 is a first step in healing the mantle.
Don’t over cleanse
Don’t over exfoliate
Use caution when using at home chemical exfoliants and peels. In order for exfoliation to occur, the pH of the product must be acidic, some acids are stronger than others. Always use a home exfoliant specifically for your skin and follow directions carefully.
If you have dry or sensitive skin, replenish the acid mantle using natural plant oils (Donna J Skincare’s are the best 😊)