why so many different types of soap
June 16, 2004 10:27 AM   Subscribe

What are the differences between hand soap, face soap, body wash, shampoo and dish soap (among others)? Is it pure marketing BS? If I (uh, theoretically) was out of face and hand soap, could I substitute, say, shampoo in a pinch? Yes, I understand that what with free will and all, I "could" use fruit punch or pretty much anything, but I'm talking about products that will actually function as passable replacements.
posted by Sinner to Shopping (28 answers total) 3 users marked this as a favorite
Well, I've seen stuff in hotels that's all-in-one soap/shampoo/shower gel. I imagine, though, that commercial soaps and shampoos have extra ingredients added depending on their intended task -- something to make your skin soft in the hand soap, something to help with your dandruff in the shampoo, and so on. It might be harmful to use these things on the wrong part of your body, although I doubt it. I'm sure some kind of soap expert will be along in a minute to give a better answer, anyway.
posted by reklaw at 10:32 AM on June 16, 2004

I would use dish soap before i would use shampoo, but that's still harsher than hand and face soap. Shampoo has more chemicals and is specifically formulated to dry out/remove product residue/strip oils/stop dandruff etc. Face soap is usually the mildest, unless it's specifically to reduce acne or oilyness. I've used body soap on my hair plenty of times and that's been fine.
posted by amberglow at 10:35 AM on June 16, 2004

I've used shampoo when the soap runs out. In my opinion it does not get me as clean. Maybe it's gentler. Soaps vary in the extent that they are an astringent (the extent that they remove oils). Removing oil is the key to getting clean. Attach that oil to a long polymer chain and it goes down the drain. Dirt is held on with oil so at that point it takes almost nothing to get clean. Taking away too much oil dries out your skin, and some areas of skin are more prone to drying than others, like your face and head.

I would guess that dishwasher detergent is the most astringent of all. It also probably has glycerin added to it though, which I believe would function as a moisturizier, and that might help.

There is also probably an issue of concentration. A little dish soap goes a long long way, I would not use a handful of it on my hair, that's for sure.

I used regular liquid bath soap when I was travelling for everything, I cleaned clothes when I had to in a sink, used it on my body and hair. But I'm a guy with pretty much no hair so, you know. And it was extenuating circumstances. I used real soap when I could find it.
posted by RustyBrooks at 10:46 AM on June 16, 2004

You can use Ivory bar soap for just about anything, including hair, dishes, dogs, floors, laundry, etc.

For laundry purposes, use a carrot peeler and peel off about 1/20th of a bar for each load of laundry.

Basically, all soaps used to be just lye and lard, with added scents or abrasive ingredients occasionally. A really nice facial soap is Castille, which is just olive oil and lard. The binding of lye and fats to make soap is called saponification.

Ivory bar soap is a lard/lye soap, that is whipped during saponification to make it light (and it makes it lather more readily).

Many modern products have a glycerine base, instead of the lard/lye standard.

Many "body soaps" of the liquid variety are made by dissolving bar-type soap in water. You can accomplish the same thing by shaving a bar of soap and letting it stand in water for a few days, with occasional mixing.

I have made some soap - lard/lye, and castille, and a special blend.

I would not use a body soap or a shampoo or a dish soap or other specialty-type soap as a general-purpose soap. But Ivory is a good general-purpose soap.
posted by yesster at 10:47 AM on June 16, 2004

I was looking for a link to illustrate the difference between soaps and detergents, but this site actually sort of answers your question directly (with a quick list of the common additives for each type) "The Soap and Detergent Association" - Gotta love industry groups for knowing their specialty.
posted by milovoo at 10:49 AM on June 16, 2004

Our in house chemist would answer this better.
My take; soap is a base and made with nature's products. Have you ever washed your hair with a bar soap? Think bar soap has more lye in it causing a harsher wash affecting the hair’s outcome.
posted by thomcatspike at 10:52 AM on June 16, 2004

Think bar soap has more lye or base in it causing a harsher wash
posted by thomcatspike at 10:55 AM on June 16, 2004

A properly made bar-type soap will be fully saponified --- meaning that there will be no residual un-reacted lye, and little to no un-reacted fats.

If the soap is harsh (after proper aging, that is), then it was not properly made.

Many hobbyist soap recipes err on the fat side or purposely include excess fat, for a softer feel. Personally I can't stand that. I want a properly balanced soap, with no excess lye and no residual fats, and no perfumes or dyes. So that's why I make my own.
posted by yesster at 11:02 AM on June 16, 2004

If this helps, we had a bit of a discussion on shampoo back here. I myself use all-in-one gel (when traveling) or just bar soap.
posted by Sangre Azul at 11:26 AM on June 16, 2004

I use Savon de Marseille (bought in bulk in a secret little store in Southern France) for everything -- my hair, my clothes, in the shower (admittedly, not for the dishes, for them I use the regular radioactive-green dish liquid soap from the supermarket). it is apparently such a chemically pure kind of soap that you can use it for literally everything -- for your newborn baby and your car

Savon de Marseille really cleans perfectly, and leaves a heavenly faint clean smell.
it is sold in big cubes of ivory-colored (or even light-grey), hard soap. don't but the beauty-product-kind Marseilles. the (harder to find) classic type is really what you're looking for

jumping in a bed freshly-made with Marseille-washed sheets is, really, heavenly
posted by matteo at 11:58 AM on June 16, 2004

Marseille is a soda-olive oil weird mix. the centuries-old traditional recipe (animal fat + wood ashes) has been modified, thankfully, during the Industrial Revolution

posted by matteo at 12:14 PM on June 16, 2004

In a pinch, yes, you can make substitutes between soaps/shampoo/detergents, depending on how harsh the soap in question is, and what purpose you'll put it to. I've used shampoo to handwash clothes when I was out of detergent, dish soap to wash my hands, body wash for my hair when I forgot to bring shampoo.... all work fine.

The products are different, and I wouldn't make most substitutions for long-term. But if you find something works okay, why not? I know plenty of (hairier) guys that use shampoo and conditioner on their bodies instead of or in addition to soap, because it makes the pelt softer. And I don't bother with liquid soap in the kitchen, I just buy dish soap I don't mind using on my hands.

I was staying over at my grandmother's right before I had my son last year, and she had a pump bottle of "Neutrogena Face Wash" in her shower. I used it and my face felt awesome, smooth and clean and soft. So I raved about it to her and she looked embarassed, laughed, and told me she was reusing that pump bottle.... that it was actually Infusium shampoo in there, and that my uncle had made the same mistake. I never would have known if I hadn't mentioned it to her because I wanted to buy some for myself!
posted by Melinika at 1:02 PM on June 16, 2004

matteo -- you say hard to find, but it seems they sell their soap on their website.

Err, I now see it says shipping on July 25, 2004. I don't know if the website is new or they're backlogged.
posted by Utilitaritron at 1:21 PM on June 16, 2004

Further regarding Dish Detergent, or specifically its' new antibacterial variants; It is intended to be used as a hand wash/sanitizer, rather than just a dish wash. The antibacterial agents play no role in cleaning the dishes.
posted by Keith Talent at 2:38 PM on June 16, 2004

the myth of superbugs?
posted by milovoo at 4:22 PM on June 16, 2004 [1 favorite]

The same detergent (or surfactant) compound is usually used in liquid hand soap, bodywash, shampoo and dishwashing liquids: sodium laurel sulphate. Since they all contain the same detergent, all the products are about the same for removing grease and oils. Laurel sulphate is a very effective detergent, "harsh", but it's cheap. It can cause skin irritation, so, in more expensive products, especially shampoos, less "harsh" (effective) compounds like ammonium laureth sulphate are sometimes used, which treat the skin more mildly.

By the way, a good explination of the technical soap/detergent difference can be found here. Short form: soaps are alkali salts of natural fatty acids (plant or animal), while detergents include a much wider range of synthetic compounds with hydrophobic and hydrophillic bits on them.

That said, there are real differences between all of the products.

Perfumes are universally added. Scent is very important in a soap. The lemon-fresh scent in dishsoap won't sell a handsoap and vice-versa for the rosewater perfume of a bodywash.

Thickeners are usually added, often in the form of gycerine, propylene glycol or derivatives.

Preservatives are added to most mixtures, in small amounts (less than 1%). Milovoo's link gives most of them.

Hand cleaners sometimes include wide-specturm biocides, "anti-bacterials", most commonly a chlorophenolic ether called Triclosan (about 95% of the market).

That's pretty much it for dish and hand soaps. Body washes sometimes add moisturisers, but otherwise, the main difference between the three products is scent.

Shampoos are the odd one out. Where a hand cleaner has to deal with grease from anywhere, shampoos deal mostly with gunk your body makes (called sebum---your natural hair oil) and gunk left behind by other shampoos. Also your scalp tends to be more sensitive than the skin on your hands, so shampoos have to be milder soaps. Finally, shampoos need to repair the "damage" caused to your hair by removing the soiled gunk.

Job one for a shampoo is getting the dirty old gunk out of your hair---that's the what the laurel/laureth sulphate does. However, if you leave your hair like that, free of all oil, protein exposed, it gets really frizzy.

As we all know, frizzy hair is social suicide. Fortunately, we can all be saved from the tragedy of split-ends if we keep the pH of the shampoo around 5-8. At moderate pHs, the protein "scales" on the outside of your hair seal up, like tar shingles on a hot sunny day. A cheap, safe citric acid buffer does this just fine, plus we can now advertise our shampoo as "pH-balanced".

Another trick we can try is adding some quaternary ammonium compounds---the same ones found on your dryer sheets and in your fabric softeners---as anti-tangling agents. These make your hair easy to brush after the shower.

Also, the glycerine or propylene glycol we add to make the shampoo less runny tend to bind water to the hair, giving it a richer, fuller feel. Now we can also advertise our shampoo as giving "extra body" to your hair. Elastagens and collagens are also sometimes added, but their effectiveness is questionable.

Now, the really fun chemistry: what if we want a two-in-one conditioner/shampoo? Conditioners add new (artificial) gunk to the hair, to replace the soiled, natural gunk the shampoo takes out. This new gunk makes your hair feel silky smooth and look shiny. The best gunks are silicones, the same class of compounds found sealing aquaria and under the hides of top supermodels. To pull this off is a really neat trick: the shampoo wants to wash away the gunk you're trying to leave on the hair. So, you need some sort of delayed action release to isolate the new clean gunk while the detergent in the shampoo washes the dirty old gunk from your hair. After the shampoo washes out, the new gunk activates and sticks to your hair making it all pretty (notice how I skip over all the interesting chemistry I haven't the foggiest about there).

We're still not done! We have to add the perfumes and the preservatives of course, but there's one key ingredient we're missing, which is, in fact, added to all of the liquid soap products. The detergents I've mentioned above have lots of great qualities: they get you really clean, they're not toxic, they don't smell, and they're very cheap to make. The biggest "problem" with them is that they don't make a lot of suds. But you couldn't sell a non-sudsy shampoo! Fortunately, that's an easy one for the might-thewed lab monkeys who cracked the conditioner conundrum: a little pantheol does the trick.

That's your average bathtub chemist's basic reaction to marketing's cry: "make us some shampoo!" The varieties of other stuff you can add are endless: egg yolk, beer, herbal infusions, "essential" oils, and so on. Most are either special perfumes, or (crap) attempts at making better "gunks".

So, to summarize: (liquid) hand soap, dishwashing liquid and body wash are all more or less the same, except for the perfumes (which often cost more than the soap, btw). Shampoo is like soap, but with a bunch of other stuff added to make your hair smooth, shiny and give it body. And that's where I stop.
posted by bonehead at 7:42 PM on June 16, 2004 [14 favorites]

This "soap" -- is it something one would need a shower or bathtub to appreciate? Heh.

But seriously -- I've used shampoo all over, in a pinch, and it seemed to "clean" and "refresh" me just fine...but soap as a shampoo didn't do anything -- just made my hair feel yucky and look worse.
posted by davidmsc at 9:25 PM on June 16, 2004


y'all need some Dr. Bronner's.
posted by obloquy at 9:37 PM on June 16, 2004

Response by poster: "bonehead":

Now that you've provided the explanation I'd been hoping for all day - thanks to everyone else, as well - I have a hard time calling you by your nickname.


Thank you for completely and totally answering my question.
posted by Sinner at 10:44 PM on June 16, 2004

Doc Bronners is just castille soap, mentioned above, plus all the fun stuff printed on the bottle, I can't read without my glasses. It smells exactly like the soap in the dispeners when I was in grade-school. Probably the same stuff.

I used shampoo on my body for years, because I don't like the residue left behind with bar soap. What some feel as "clean", I feel as coated with gunk. Now, shower gel is available, and seems better. My imagination?

If your hair appears lifeless, you could buy "clarifying" shampoo. Or, you could just slap on some dishliquid, then apply a decent conditioner afterwards.
posted by Goofyy at 11:21 PM on June 16, 2004 [1 favorite]

it seems they sell their soap on their website

they do, but it's not the particular kind I buy -- Marseille has become pretty common in Europe because it's so good. but there's many different kinds. it's usually the older, smaller labs in the Southern France that make the best Marseille
posted by matteo at 4:23 AM on June 17, 2004

In awe of bonehead.
posted by CunningLinguist at 5:25 AM on June 17, 2004

It's worth pointing out---I didn't above because my blort was already getting too long---that castille soap is a real soap, in the strict sense. It's an ionic salt of a (usually) natural fatty acid. The sodium laurel sulphate is not; it's a detergent in the strict sense of the term. So, if being "organic" is important to you---which I interpret as not wantig to use the products of the chemical industry---you might feel better choosing the "natural" alternatives like Dr. Bronner's.

I have some problems with that. How much different is a soap factory with "organic" inputs from a reactor line in New Jersey? Not much from a chemical purity or environmental effects point of view. Arguably, that NJ plant has a smaller impact on the environment than a "bathtubber" who'se less than careful with their wastes.

However, in terms of the effects on your skin soaps are much less "harsh", which can be a real plus if you have sensitivities to detergents as some people do. The trade-off is that soaps are a wee bit less effective at removing oils and dirt, but it's not a huge difference. Ivory really is milder.
posted by bonehead at 7:26 AM on June 17, 2004 [1 favorite]

great info. one other thing that will determine how well a given soap or detergent will work for you is the acidic/akali content of your water.

any of you chemist soapistry experts want to explain that one? i used to do marketing for showerheads, but i've forgotten.
posted by th3ph17 at 8:54 AM on June 17, 2004

As I understand it, soap effectiveness is mostly limited by mineral content, that is to say water hardness.

Soaps are ionic compounds: they split into a (small) positive and (very large) negative chunks in water. For example: sodium laurel sulphate is: NaCH3(CH2)11OSO3. In water it breaks into two bits: Na+ and [CH3(CH2)11OSO3]-

In hard water, there are a lot of metal ioins floating about, magnesium, Mg2+, and calcium, Ca2+, are the most common. Soaps like both of these things more than they like the sodium, Na+, they come with. So the soap, that long negative thing in the square brackets above, grabs ahold of the magnesium or calcium ion and holds on. In fact, two soap ions can grab onto one magnisium or calcium, but that's just a detail here.

Now, the soap+magnesium combo, Mg[CH3(CH2)11OSO3]2, doesn't like being in water very much so it falls out of solution. This is soap scum. Bacteria seem to love it and their poop turns it pink.

That's how hard water makes soap less effective; it knocks the soap out of the water so that it can't grab the grease and dirt from the thing you're trying to wash. All soaps and some detergents behave this way. Some detergents don't break into positive and negative bits and thus work fine in hard water.
posted by bonehead at 10:53 AM on June 17, 2004 [1 favorite]

Ah, I thought there was only one maker....
posted by Utilitaritron at 3:38 PM on June 17, 2004

Wow, this has been such a great thread. Loads of great info bonehead, thanks!
posted by dejah420 at 10:26 PM on June 17, 2004

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