You know, that’s what I was going to say as well, especially since the OP’s hair in question is about the same length (or even shorter) than those other body hairs. I’ve never used bar soap on my own hair (I have used body wash, though) but I’ve heard that some people do, so the idea to use that would have occurred to me long before the thought of using the bottle of Joy by the kitchen sink.
astro prides himself on thinking outside the box, at least when it comes to the interchangability of kitchen and bathroom cleaning supplies.
Ask him about this pot-scrubber.
When I go on a trip, especially backpacking where space for items is at a premium, I always take a mild dishwashing liquid, because it has three uses in one: washing the dishes, washing the clothes and washing myself (including my hair). From personal experience I can say it works without a hitch.
I have been using concentrated dishwashing liquid in the shower for about 8 or 9 years now. It works just fine for all my showering needs, including washing my hair. Hairdressers do sometimes take me to task for having hair that’s too dry, but I’ve never really been able to figure out what’s so bad about that - seems to me the only thing that extra oil would be doing is dirtying my pillow at night. (I do keep it quite short and don’t have to worry about it breaking or splitting.)
He’s not a pothead, is he? 
FWIW, perfumes and additives are going to be the major differences in different brands of shampoos. Joy (of any scent/color/flavor) is not dangerous to use, although it might sting quite a bit more and have more surfactant than normal shampoos. Non-tear formulations of shampoos have a different caustic than regular shampoos and LDL detergents, IIRC. The same “base” goes into making shampoos, LDL detergents (dish liquids) and HDL detergents (laundry), more or less. The viscosity is different, and the base for non-teat shampoo formulations are different. As for soaps, “natural” soaps (made from saponification of animal or vegetable fats) are of course different from synthetic soaps. Ivory is a natural soap, and I suspect that the Neutrogena and similar lines are; Zest is a synthetic.
Ivory Snow or Ivory Soap flakes are natural “detergents” for laundry and other uses. Dreft is pretty much the same stuff (same company). They are soaps that are chipped or flaked. Synthetic granule detergents are made by a process where the detergent is dried in a tower and settles out into a granule.
Thanks muchly!
I spring for high-priced hair care products (Nexxus Therappe and Humectress). And they really do make my hair feel and behave differently. So what is doing that? Sounds like maybe the shampoo is similar to cheaper ones but the conditioner is what is making the difference?
To disagree slightly with the master…
By “healthy” I don’t think one means that hair is alive, or that it is somehow rebuilding the proteins. But just because something is dead tissue doesn’t mean that it is inert, or that it can’t be treated to change its strength, flexibility, resiliance, etc. Think of hair as being like your wood patio deck. They are both completely dead tissue, but you have a huge amount of control in how you can maintain the strength, color, hardness, and lifetime of both materials when exposed to the outside elements. It just takes the right chemical to either seal, moisturize, coat, whatever. You can give shine and life to your car paint job with the proper chemicals also, even though it is not alive.
I wouldn’t blithly dismiss effectiveness of conditioner just because hair is dead tissue.
Ahhh, but Cecil is the King of Blithe…
OK, well maybe Earl, or even Duke.
But it’s still Blithe.
The reason given me about why it’s ok to wash your head with bar soap if you have short hair is simply that soap does the job, and the hair on your head isn’t going to be there long enough to get damaged, i.e. develop split ends or something.
One thing you can’t use regular dishwashing liquid for: I had a boyfriend once who had just bought his first place, and didn’t have any dishwashing machine detergent, so he just used a few squirts of regular dish soap. Much hilarity ensued. Foam party in the kitchen!
Well, those of us who know what we’re doing with our beards use shampoo on them as well.
Basically, you use shampoo on any hair you want to be manageable afterwards. I’m not in the habit of combing my underarm hair, so I don’t bother with shampoo there.
Detergent, cheap shampoo and expensive shampoo are not the same. You’d might as well say that corn liquor, boxed wine, and Champagne are all the same. If all you want to do is remove oil/get drunk, then it doesn’t matter. But if you want to achieve a particular asthetic effect, they are vastly different.
Oh man! You’re right, I really ****ed up! Now I won’t be able to get a comb through it!
Eh, maybe, maybe not. My grandfather uses bar soap on the little hair he has left…and it shows. His hair is all matted and greasy looking.
My aunt and uncle will do the opposite-use laundry detergent when they’re out of dish soap. I was staying at their house for a week once, and had to use it to wash the dishes-YUCK!
No, not true. Yeah, I (as someone who does way too damn much with my hair) will agree that shampoos differ, the price is anything but a reliable indicator of their quality. Expensive shampoos, “salon” brands, and so forth, are on the whole no better than the stuff in the grocery aisle - but on the other hand, there’s good shampoos and awful ones in both places.
Someone above asked about Suave, and Suave in particular uses harsh detergents, but if you’re not having problems with your hair (as in dryness or fading of hair dye) then it’s not a problem and you shouldn’t worry about it. The basic chemistry is the same from product to product, but some shampoos use harsher detergents that will strip the oil a bit too effectively from your hair, and if it’s long enough to tangle, it’ll get tanglier.
Friends have used dish detergent to remove semi-permanent hair colors, so that suggests to me that it’s probably a good deal harsher than shampoo, but it’s not different on some fundamental basis, either. And you can find 89-cent shampoo that’s perfectly fine; no one washes their hair with the right shampoo and finds it immeasurably changed like the ads say. The differences are subtle at most, and there’s plenty of expensive shampoos that are godawful.