Why is detergent in soaps bad for your skin?


I keep seeing all these ads for natural soaps that say they are good because they are detergent free, but never explain why detergent is bad. Did I miss something or is it just a marketing gimmick?

In: Biology

As far as I know, detergents (in high concentrations) react with and destroy:
1) all the oils you have on your skin
2) and also lipids that build up your skin cells and thus literally killing your lovely skin cells

Mostly it’s a marketing gimmick. Over-soaping can dry out your skin and some people have allergies to consider but most people are perfectly fine with most soaps as long as they’re not going nuts with it and don’t have said allergies or particularly sensitive skin.

Detergents are fine and dandy for clothes and cleaning. Your skins oil are a protective layer that should never be habitually stripped in their entirety. Otherwise it will disrupt the protective layer, the ph balance, and cause all sorts of long term skin problems. Yes, some people’s skin is made of iron but in general it’s good practice to use mild soaps on your skin.

I am not an expert but I make soap. This response comes from that experience.

Soap, by chemical and US FDA legal definition, has a certain pH and is made by combining a basic solution with a lipid. In terms of what I make, this means taking sodium hydroxide lye and mixing it with oil to get a bar of soap with a pH of 9 or greater. If you want liquid soap you would use potassium hydroxide. Commercial products made this way are Irish Spring or Dr. Bronners

Synthetic detergents (syndets) are made by extracting chemicals from natural sources and combining them to create your soap-like product. I don’t use synthetic detergents so I’m not 100% on everything. Syndets work the same as soap but can be pH adjusted (no more tears) or you can easily play with the consistency to get a thicker product. Legally they cannot be labeled as soap so companies play with words and you get combinations like Dove’s Beauty Bar or Soft Soap or “oil free acne wash.”

Syndets work the same as soap, they get you clean and are effective against most germs/bacteria/viruses. At its base, the differences between soap and syndet are similar to the differences between canola and peanut oil and coconut oil. There are specific purposes for each but the home user can probably interchange them without much issue.

The problem with syndets is that most soaps in the hygeine aisle are syndets these days. It’s easy to find out if you’re allergic to peanut oil but if you’ve only been exposed to syndets you won’t know if you’re allergic unless you do a bit of research research find something else.

In the soap making groups I belong to there are big discussions about skin feel between the two. There is nothing inherently wrong with using syndets if you choose to. Some people find them too drying, which can make them break out. Those people can benefit from switching to soap.

On a personal level I’ve found differences between using the “hand wash” at work and using “real soap” at home, especially during the winter. My husband chooses to use commercial body wash due to texture issues. You choose what works for you but now you know that there are other options out there.

Like others have already said, detergents can dry out your skin. It can be bad enough to give you eczema, which is not fun to deal with; from then on, your skin is never the same.