I should have better things to dedicate my thoughts to, but this has stumped me for quite a while.
Shampoo is like a soap, right? One end of it is attracted to water, one to oil. So traditionally, you needed to shampoo your hair to remove the oily build-up, then rinse that off and apply conditioner for that oily (but nice-oily) finish. Why doesn’t the conditioner in 2-in-1s cancel out its shampoo and vice versa? How is it possible to form a lather? Is it really cleaning my hair?
Please someone, answer this. I’ve wanted to know it, too! My fiancee insists on 2-in-1, but I’m convinced it doesn’t give his hair the love it should.
I use 2 in one and I’m happy with it. I’ve never noticed any difference from conditioner, though…I’m not sure it makes a difference to me.
The cleaning ingredients in shampoos are, for the most part, anionic surfactants – a small negatively charged head with a nonpolar tail. The conditioning ingredients in conditioners are usually cationic surfactants, almost always quaternary ammonium compounds – a nitrogen atoms with four organic substitutions. The challenge with a 2-in-1 product is that normally the cations and anions will react, producing something that looks like cottage cheese and feels like wax. There are a couple of ways to prevent this.
One way is to use a conditioning ingredient that won’t precipitate with the anionic surfactant – I’ve seen cationic-substituted polymers used for this, like a quaternary ammonium compound with guar gum or hydroxyethyl cellulose as one of the substituents.
Another way is to shield the conditioning ingredient until rinsing. In this case, the conditioning ingredient is usually a small neutral organic molecule like dimethicone or dimethiconol. This small molecule is pre-mixed with a carrier that will resist being washed away by the surfactants. I’ve never been involved in making one of these, but it seems likely that an anionic polymer would do the trick – during rinsing, the polymer is stripped away by excess water, leaving the silicone to form a thin layer on the hair.
On a related note, one day I ran out of shampoo, so I decided to try some laundry detergent. It got my hair cleaner than I’ve ever seen it (although it also made my scalp a little red for a bit). I was so pleased with the result that I called Tide’s 1-800 number to let them know of my discovery. When I told the nice lady on the phone about it, she became quite agitated.
“WE DO NOT RECOMMEND THE USE OF TIDE IN YOUR HAIR,” she shouted.
I tried explaining to her that I wasn’t calling to complain, and that I had no intention of suing anyone, and just wanted to let them know that their product worked very well as a shampoo, but she just kept shouting at me, “WE TAKE NO RESPONSIBILITY FOR THE USE OF TIDE ANYWHERE ON YOUR BODY.”
Go figure.
I think the shampoo makers touted the idea of the 2 in one just to sell more products, or maybe customers thought it was more convenient (eliminating two separate products, saving space in the carrier bag when travelling). It always left my hair gummy and limp the next day, too hard to rinse out or too much conditioner, not enough shampoo.
Does conditioner actually do anything anyway? I can’t say I have ever noticed the difference between using plain shampoo, shampoo followed by conditioner, or a 2-in-1 product.
I always figured that “conditioner” was just one of those ways to make people fork out for a bottle of what’s basically perfumed water with a bit of thickener in it.
I would think that laundry detergent would do too good a job of cleaning your hair, possibly even damaging its cuticle.
I was once forced because of money issues to buy a sample size bottle of shampoo that smelled exactly like industrial floor cleaner. I remember thinking to myself that if my hair fell out after it, I’d have no one to blame but myself for spending all my money on pizza.
Of course, my hair all fell out later, but that was father time’s doing, not Dow Chemical.
You must be either very young and uninformed about such a common thing as conditioner for the hair, or a man. Who doesn’t color, perm, highlight, or otherwise do anything with his hair. Having things done to your hair, especially involving bleach, really messes up the cuticle, and without conditioner to smooth it down, you come out of the shower looking like there’s a tumbleweed on your head. It’s a hideous sight, you can’t even get a comb through it.
You buy one of them but pay the price of two of them. Thus 2-in-1.
I’m sure I’ve linked this article before. I’ve quoted the portion that answers the question (basically what Nametag has already said).
http://www.rsc.org/chemistryworld/Issues/2005/January/Taketwobottles.asp
Got it in two. 
FUCK! You mean I figured all that out from reading ingredients and patent applications, and I could have linked to an ARTICLE?
I’m female, but my view on conditioner was the same. Of course, I also don’t do anything harmful to my hair, but other than the time I once used a shampoo that just didn’t agree with my hair, I haven’t really found a need for conditioner. I use the 2 in one stuff, but I’m not sure there would be much of a difference without conditioner.
I read an interesting article a while ago about how to get the best results from 2-in-1, but I just can’t find it again. All I remember is that it’s dependent on the amount you use and the time you lather. I know that’s not much to go on.
It also depends on what kind of hair you have. My sister has very fine, straight hair, and doesn’t really need to use a conditioner. I have very thick, coarse, wavy hair. If I don’t use conditioner, I’ll be spending at least half an hour after my shower trying to untangle my hair without ripping it out - as opposed to 15 seconds to run a comb through it when conditioned.
you can do your own 2 in 1 shampoo/conditioner.
Put a dollop of shampoo and condition into your hand and VIOLA! It saves you approx. 1.4 minutes of your time. YMMV.
the conditioner is a form of wax and not as attractive to the detergent as oil is. Hence more wax is left behind than oil.
From the posts by people who actually knew what they were talking about, it appears that the story I heard about conditioner being wax is wrong. Apparently it is a silicone lubricant(?). Close, but not the same.
As well as the length. When I had long hair, I could use just shampoo or two-in-one and my hair would be a tangled mess that I couldn’t run my fingers through. I took a shower at my mother’s house once and used some of my stepsister’s conditioner and my hair was that good oily with no tangles. I started using it after that.
Now I have short (and somewhat sparse) hair and I don’t need the conditioner so much. I only use it every once in a while.