I’ve heard before that washing heair, or at least rinsing it, with cold water helps give volume and whatnot. But recently, I’ve read that using cold water is “little mroe than self-punishment.” Is there any benefit at all from using cold water to rinse? Thanks in advance if anyone can answer this. =)
The only evidence I can give is anecdotal. After conditioning (not just washing), I find that an additional rinse with cold water gives my hair more shine than simply rinsing with warm water.
I’m sure that there are many factors involved, such as hair type, minerals in the local water supply, and the brand of conditioner used, but it seems to work for me.
If you’re careful, only your head will get the cold water.
Welcome to the Straight Dope Message Boards, liz75, we’re glad to have you with us.
You’ve put this post in a forum dedicated to comments on Cecil’s past columns. I don’t think that Cecil has written a past column on this. There is a past Staff Report that is sort of vaguely kinda partly related, perhaps: Straight Dope Staff Report: What’s more important in cleaning, soap or hot water?
However, your question is different enough that I’m going to move it to the forum called “General Questions,” where I think you’ll likely get more responses.
No big deal; as you hang around here more, you’ll learn that our classification system isn’t as random as it appears. Well, mostly it’s not. Well, hardly ever.
Again, welcome!
Again, anecdotal, but there absolutely no question that it seems to give hair more ‘poof’, and gives it a slightly thicker appearance.
This is purely anecdotal as well, but I’ve found that when I use cold water on my hair my hair gets wet and cold.
I was under the impression that soap doesn’t get ‘sudsy’ in cold water. Becuase of this I suspect cold water does a better job getting all the left over residue out of your hair.
When I had a streak of my hair dyed blue, I was supposed to rinse it in cold water to prevent the color from fading. I never did, though.
From what I understand, the cold water rinse keeps the natural oils (as well as added on conditioning agents) from dissolving as much.
Which is contrary to the notion that it adds volume - more oils and conditioning agents left on the hair means it’ll be heavier and more limp. Besides, shampooing is done to get rid of those old oils, before they go rancid or attract bugs.
The supposed mechanism I’ve heard is that it causes the cuticle - the outer layer of hair, which takes the form of overlapping plates - lay down more smoothly. But I don’t see why that should last after the hair dries. I suspect that it’s not true. I don’t put much weight in anecdotal evidence, because people really tend to see what they expect to see, and there’s a million different things that can affect how your hair looks. If the weather’s just right and it happens to correspond to a day you rinsed your hair in cold water, then it’ll seem like one caused the other, and you’ll remember the coincidence.
I used to use cold water to rinse off soapy dishes and was mocked into comforming to the warm water standard. I made the same assumption about cold water rinsing away more soap.
As for anecdotal information, I wash my hair with generic shampoo, brush it afterword and rarely look at it again.
The problem with rinsing dishes in cold water is that they won’t dry as quickly. If you use hot water, they’ll dry in a couple minutes.
Ouch, you let some mocking change your behavior? 
I still stand by cold water not sudsing soap… and in your case that makes cold water better for rinsing. However, dry time usually isn’t a factor for me…
For what it’s worth, I was my hands in hot water than rinse in cold water… feels like there is less soapy residue on my hands afterwords.
Well, before this falls off the front page and we lose all hope to settle this pressing matter once and for all…
It seems to me that:
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Hot water would rinse your hair better, because the soap would then be more soluble.
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Cold water would rinse your hair just fine, if you did it long enough.
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Assuming your hair was rinsed thoroughly, if you blow dry your hair, it wouldn’t make any difference anyway.
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Even if you didn’t blow dry your hair, it would be room temperature before it dried.
Given these assumptions, I don’t think it really matters.
When I heard the “rinse your hair last in cold water” thing the logic behind it was that the astrigent action of the cold water stopped your scalp adding oil to your now clean hair. Rinsing in hot water supposedly encouraged the secretion of oil.
You’re right. I’ll never let it happen again.
I was not able to convince my mockers, much less myself, that the lower solubility would make cold water better. The idea being, as What Is Schwa has said, that lower solubility equals less sudsiness. The water wiskes the soap away instead of merging with it.
I personally decided the distinction was too subtle to be worth quibbling and now use either or both. (Both being tepid water.)
My personal theory about this is that rinsing with cold water rinses your hair from a different angle.
Because cold water is so frickin’ cold, when I used to do this, I would always bend over and spray my head from above so that none of the cold water would get on my body. My theory is that the way my head was turned, more soap would rinse out of my hair than if I stood up in the shower and rinsed my hair the normal way.
What I’d always heard was that a final rinse with cold water seals the hair scales so your hair looks shinier. Here’s a cite with absolutely no scientific backing. I think it’s a bit of popular beauty “wisdom” that’s probably never been researched.