Sunday, February 24, 2008

Soap vs. Detergent

There's a lot of confusion out there about detergents and soaps. Some companies say that their detergents "don't dry your skin out like soap" and some soap companies say their products "don't irritate skin like detergents." So who's right? What's better--a soap or a detergent? Let's start out with the basics by looking at how each is made.

Detergents (or surfactants) are synthetic compounds that have been created through a chemical process. The most widely-used detergent, sodium lauryl sulfate, is created by reacting sulfuric acid with dodecanol (a fatty alcohol) adding a few other chemicals, heating it up, adding more chemicals, and so forth. On average, there are about ten steps between the original raw materials and the final detergent. Soaps on the other hand, are created by mixing a fat (usually a vegetable oil) with caustic soda (like lye or potassium hydroxide). Soaps have been created like this for hundreds (maybe thousands) of years. Detergents, on the other hand, have only been around for a few decades.

It can be confusing because often detergents are packaged like soaps. Most of the commerically produced "soap" bars out there aren't really soaps at all. Look carefully at their packaging. Do they list a bunch of chemicals? Some common ones would be cocomidopropyl betaine and sodium laureth sulfate. If there are a lot of confusing chemicals listed, you've got a synthetic detergent. Legally, detergents cannot label themselves as soaps. You'll notice their packaging will say "facial bar" or "body cleansing bar." On the other hand, if the package lists oils and "saponified" oils, you're using a true soap, not a detergent. Detergents and true soaps can be both liquid and solid.

So, now that we've established the chemical differences between detergents and soaps, let's get down to the real question: what's better for my skin?

I've been asked this question a lot and a recent roadtrip from Salt Lake to Denver gave me a fresh perspective on the matter.

We drove at night through the cold and windy plateaus of Wyoming. Halfway through the trip, I noticed my hands had become extremely dry and papery. They looked like old witch hands! At first I thought it was my sleep deprivation. I hadn't slept much the night before and when I'm short on sleep my skin feels out of whack. But no, this was something else. The wind? The cold? Utah's just as cold and dry as Wyoming, so that shouldn't be it. Then it hit me: I had washed my hands at the pit stops along the way!

You know what I'm talking about--the gooey pink stuff that comes out of the dispensers at public restrooms. At home I've been exclusively using our bar soaps to wash my hands. But these detergents were stripping my skin! So that gives us our answer, right? Soaps are more gentle than detergents.


Let's rewind two and a half years.

When I first started doing research for Bubble and Bee, I ordered some organic liquid castille soap. I loved how it smelled and how it foamed up. But after using it on my hands, they turned into sandpaper. They were cracked and dry and I had to stop using it.

So, what's the deal? Are they both bad for your skin?

The real answer is that both soaps and detergents can be both harsh and both can be gentle on your skin. The hard part is knowing what to look for.

I've researched a lot of detergents and the only one that I allow in my products is decyl polyglucose. It's made from the sugar extracted from corn and I've used it at full strength on my skin. If you were to pour straight sodium lauryl sulfate on your skin it would burn. But I've poured decyl polyglucose at full strength on my skin and it doesn't irritate it at all. In fact, since I've got a big supply of it here, I use it as my dishwashing soap. It doesn't dry out my hands and gives me plenty of bubbles. I won't pretend that it's a truly natural substance, but as far as detergents go, it's the best out there. It scores a zero risk through the Enivronmental Working Group's Skin Deep Database and is highly biodegradable.

Soaps are the most natural option, however. The only time I use decyl polyglucose is when I can't use a soap. I can't add a soap to our salt scrubs because salt coagulates the soap. So, to get a nice safe lather in our salt scrubs, I use decyl polyglucose.

The key to finding a great soap is to look at the ingredients and the bar itself. Use bars that are made from vegetable oils, not animal fats. Vegetable oils like coconut, palm, and olive oils will be more gentle than animal fats. (Ivory and Dial, by the way, are made from animal fats sourced from rendering plants.) Also look for soaps with retained glycerin and even added glycerin. The more glycerin, the more gentle the soap will be. Glycerin is a natural component of oil that becomes separated from the oil when you make soap. Glycerin will actually draw moisture from the air to your skin, keeping it moist throughout the day. The softer the bar, the better. Softer bars usually mean more glycerin.

If you're looking for a true liquid soap (not a detergent) also look for those with added glycerin. Liquid castille soaps can be harsh, but those with added glycerin and oils will be more gentle on your skin. Formulas like our shower gels are an example of a true liquid soap with added glycerin and oils.

What are your experiences? Do you prefer detergents or soaps? I'd love to read and respond to your comments below.

Happy scrubbing!


Chemical Free Shower Gels Organic Soaps Organic Deodorants Organic Hand Lotion Organic Lip Balm Organic Gifts Organic Salts and Scrubs


Steve Thomas said...
This comment has been removed by the author.
Anonymous said...

I just viewed this blog on soaps vs detergents and enjoyed it very much. I do find myself reading the list of ingredients more and more, and not just on foods.

Anonymous said...

Your right. Truck stop "soap" is a skin killer.
I've tried several different natural soaps. Some are really good,
others felt like they were taking my hide off.

A friend of mine has made soap from scratch. He was telling me that
there is a fine line, for adding to much lye, or not enough.
To much, and the soap is harsh. Not enough and it wont set up. Dose
this sound right to you?

Do you know if time is a factor? It felt like some soaps get better
with age, or did I get use to them?

Stephanie Greenwood said...

Thanks for leaving your comments! Yes, time is a factor. Soaps usually need around 4 weeks to cure properly. The more it's cured, the more gentle it will be.

And it is a fine line between too soft and too harsh...soap making is a science and an art!

Anonymous said...

I'm a new mom and I'm looking for baby wash that's right for my 3 month old. I've tried lactacyd and johnson and johnson's but I've read about toxic ingredients so now I'm checking. The problem is I've read that baby skin's pH is 5.5, below and above can harm the baby's natural skin chemistry. Can bubble and bee make cleanser with decyl polyglucose base and organic oils and a pH of 5.5? Sebamed has pH of 5.5 but they contain lots of toxic ingredients like SLS. I'm using right now an organic liquid soap with castille soap as base.

Anonymous said...

I'm just wondering how they extract the sugar from the corn? Is this a safe process that won't harm the environment?
I'm looking forward to trying some of your products!

Susan said...

An experienced cold process soap maker will always use less lye than the amount necessary to saponify all the want some extra oils in the bar. The term is called "super fatting". You want some extra fat for moisturizing but not too much that the soap doesn't clean. They also discount the water to make a harder bar, but if you discount too much...there is not enough water to dilute the lye and have the correct mix to saponify. There is definately a lot of skill and experience necessary to formulate a great bar soap...but luckily there are thousand of great soaps to pick from.

Susan, former VP; Secretary and Treasurer of the Handcrafted Soap Makers Guild, Inc.

Chris said...

haha this is perfect for my science research on the difference between soap and detergent

Anonymous said...

Thank you for posting this thoughtful and informative blog. In chemistry class I was taught that soaps are detergents, specifically anionic detergents. If soaps are detergents, is it logical to speak of soaps vs. detergents?

Stephanie Greenwood said...

I think that the word you're thinking of is probably "surfactant" not "detergent."

Anonymous said...

I'm confused. If detergents cannot be labeled as "soap," how do all the "liquid hand soaps" and even SoftSoap brand get away with calling themselves soap?

Anonymous said...

I know that saponified soaps do not need preservatives, only antioxidants. What about decyl polyglucose? Does it need any preservatives? Thanks!

Stephanie Greenwood said...

That would depend on the overall formulation and dilution rate. :)

Anonymous said...

Stephanie, thank you so much for a quick reply! Here are the ingredients of a shampoo, "Purified Water, Decyl Polyglucose, Vegetable Glycerin, Organic Apple Cider Vinegar, Organic Unrefined Shea Butter, Organic Lemon Essential Oil, Organic Rosemary Essential Oil." The shampoo maker claims that they do no need a preservative because the shampoo is not emulsified. And a preservative would be only needed if water was used in the emulsification process. Please let me know what you think. Do you think there is an undisclosed ingredient in this formulation. I really appreciate your work!

Stephanie Greenwood said...

Oh wow--if they told you that a product doesn't need a preservative because it's not emulsified, they definitely don't know what they're doing. Yikes! Anything with water needs some form of preservation.

Stephanie Greenwood said...

(And technically they are emulsifying here...they're combining water with oil (shea butter) with the surfactant properties of decyl polyglucose.)

Anonymous said...

Soft soap has both detergent (sulfates) and lye (sodium hydroxide) listed in their ingredients

Jugal Kishor said...

Does this blog contain information on how to make a soap?