Written by Dr. Joshua Townley, BForensSc, PhD.
The difference between soap and soap-free
Have you ever wondered why some cleansers claim to be ‘soap-free’? If they don’t contain soap, what’s in them, and are they as effective? On the surface, both soap and soap-free cleansers do exactly the same thing, they clean the skin. However, because of the way soap is made and the ways it interacts with the skin, the choice you make can have a big impact on your skin health.
The pH levels of traditional soap
Traditional soap, often a colourful, scented bar, is made through a process called saponification, which involves treating vegetable or animal fats with a strong base. This causes the soap to have a very high pH of around 101. Our skin has a slightly acidic pH of 4-5 and it’s been shown that washing with soap raises the pH of the skin temporarily2. It can take more than 6 hours to return to normal. A soap-free cleanser that’s pH-balanced, on the other hand, has no more effect on skin pH than regular tap water2.
Dr. Joshua Townley
The pH properties of a skin barrier
The skin barrier, which helps keep moisture in the skin and environmental irritants out, works best at a pH of less than 5. At higher pH, which can occur after washing with soap, the skin loses water more quickly and appears drier2. Because they are so effective at removing oils, soaps can also disrupt the natural skin barrier, essentially poking holes in it, leading to further water loss1.
Tips for sensitive skin
Another way soaps can affect skin health is by disturbing the natural bacteria that live on the skin. Known as the skin microbiome, this complex assortment of microbes is vital to our skin health3. When the pH of skin is raised, harmful pathogens like staphylococcus aureus thrive, while a low pH is better suited for the beneficial staphylococcus epidermidis, a bacterium that helps with our immune response and barrier function4.
If you’ve still got a bar of soap sitting by the bathroom sink or in the shower, consider swapping it out for a soap-free cleanser. Both are equally effective when it comes to washing away dirt and germs, but you’ll find a pH-balanced soap-free cleanser much gentler on sensitive or dry skin.
