July 12, 2024

The pH of Soap Explained

The pH of Soap: Everything You Always Wanted to Know But Were Afraid to Ask

Skincare Secrets: Episode 2

Before we get to pH, the first thing to understand is that are two types of cleansers: soap and detergent. They're not the same. More on the difference shortly.

What's the pH of Soap?

All real soaps, including S.M.O.C. Skincare soaps, have an alkaline pH, usually 8 to 10. It's basically impossible for a real soap to be pH neutral (7). Soap can only be alkaline. Only detergents can be pH neutral or acidic. Many bar 'soaps' (like Dove, Ivory, etc.) are actually detergent mixed with some soap, or just detergent bars. If a bar 'soap' is marketed as 'pH balanced' or 'pH neutral' that means it's not real soap, it's a synthetic detergent that's being called 'soap.' This is why detergent bars are labeled (correctly) as "beauty bars" not "soap bars." But not all companies label correctly.

What's the Difference Between Soap and Detergent?

Soap is a natural cleanser made from plant oils or animal fat. Soap has been used for over 2,000 years to safely clean human skin.
Detergents are synthetic cleansers made from synthetic chemicals, like sodium lauryl sulfate. Body wash, shampoo, and most liquid 'soaps' are detergents. There are hundreds of chemicals that are used to make detergents and if you look at the ingredients list of a detergent bar or a body wash you'll often see dozens of chemicals. Detergents were invented in the early 1900's by German chemists and were originally intended for cleaning surfaces and fabrics, not human skin.

Do Soap and Detergent Change the pH of Skin?

Companies that sell detergents and detergent bars (which they may market incorrectly as 'soap' bars) claim that 'pH balanced' or 'pH neutral' detergent is better than real soap. That's not the case, because:

Real soaps are only mildly alkaline (8 to 10 usually) and because soap is a rinse off product, soap won't change the pH of your skin in a meaningful way. One study found that the difference between washing with soap vs detergent was just a 0.1 change in skin pH.
Detergents are closer to the skin's pH which is theoretically good, but the downside is the following:

🫧Detergents are made from synthetic chemicals which means you are putting synthetic chemicals on your skin. Real soap is a naturally-derived product so you're not putting chemicals on your skin when you use soap. (But it's important to read labels because some soaps contain chemical additives.)
🫧Detergents are, by their chemical design, harsher cleansers than soap, and can strip the skin of needed oils. Imagine washing your body with Tide laundry detergent. It would strip all the oils from your skin because it's a harsh, powerful cleanser. Most manufacturers mediate the intrinsic harshness of detergents by adding more chemicals such as synthetic moisturizers (like EDTA) and skin penetration-enhancing chemicals which can allow the synthetic moisturizers and other chemicals to penetrate into your bloodstream.

Which is Better?

Because detergents are synthetic cleansers that contain a multitude of chemicals, many of questionable safety, we believe that soap is the better, healthier choice. That's why we only make real soap, not detergent. S.M.O.C. Skincare soaps are also completely free of chemical additives like colors, fragrances, and preservatives.