From: larry@kitty.UUCP (Larry Lippman)
Date: Tue, 26 Dec 1989 18:54:12 GMT
Subject: Re: How does Ultraswim Shampoo remove chlorine?
Organization: Recognition Research Corp., Clarence, NY
Newsgroups: sci.chem,sci.med,misc.consumers
Keywords: chlorine
Lines: 180
Summary: Everything You Ever Wanted to Know About Chemistry of Shampoo :-)

In article <5775@ncar.ucar.edu>, ilana@cgdra.ucar.edu (Ilana Stern) writes:
> The copy on the Ultraswim bottle (a shampoo for swimmers) claims:
> 
> "Chlorine chemically bonds to hair, actually changing its structure.
> Ultraswim gently unlocks these bonds and gets the chlorine out.  No
> other shampoo can do that."
> 
> 1) How does chlorine bond to hair?

	Human hair is largely comprised of protein in the form of a-keratin,
whose major constituents are amino acids.  In the particular case of human
hair, the most abundant amino acid is cystine, which accounts for about 15%
of the composition.

	The chemical reactions involving the exposure of human hair to
water containing free chlorine are complex, and depend upon many factors,
including but not limited to:

1.	Type of chlorinating agent.  Larger municipal pools employ direct
	injection of liquid chlorine.  Smaller municipal pools and home
	pools generally rely upon sodium hypochlorite (which results in
	accumulation of sodium chloride in the water, in addition to
	availability of sodium ions) or upon calcium hypochlorite [sold
	as HTH] (which results in accumulation of calcium chloride in
	the water, in addition to availability of calcium ions).  Other
	chlorinating agents, such as chlorinated cyanuric acid, may also
	be used.

	While free chlorine is free chlorine, the possible concentrations
	of sodium salts, calcium salts and other agents such as cyanuric
	acid have their own effects upon hair.

2.	Presence and effects of pH control agents and algaecides found in
	municipal swimming pools and larger home swimming pools.

3.	Effects of pre-existing chemicals in the hair as a result of
	dyes, permanent wave treatments, conditioners, etc. 

	While some general predictions can be made for the effects of
chlorinated swimming pool water upon human hair, there are far too many
variables for any "swimmer's shampoo" to have any consistent beneficial
effect that is ANY DIFFERENT FROM A "REGULAR" SHAMPOO. 

	When hair is exposed to swimming pool water containing chlorine and
possibly other chemicals, the most significant effect upon the hair is
caused by the WATER ITSELF.  Upon exposure to *just* water, the a-keratin
in hair begins to hydrolyze, forming (among other products) cystine, which
further hydrolyzes to form cysteine.

	It is interesting to note that water containing chlorine will cause
the above reaction to reverse to the extent that the thiol groups in
cysteine will oxidize so that two molecules of cysteine will rejoin to
form cystine.

	While admittedly stretching the imagination a bit, it could be
argued that the presence of chlorine may have a *beneficial* effect upon
hair to the extent that it mitigates some deleterious effects of water.

	But wait, that's not what the advertising implies! :-)

	The hypochlorous acid resulting from chlorine in water will, to
some extent, combine with amino acids such as cystine to form cystine
hydrochloride and with cysteine to form cysteine hydrochloride.  However,
in my opinion, it would appear that the above reaction, as an example,
is not particularly significant when compared to the effects of water itself.

> I don't doubt that it does, as when I go to get my hair cut it's not
> uncommon for the hairstylist to comment on the chlorine damage to
> my hair.  (Which is why I bought this special shampoo.)

	Is it *really* chlorine damage, or just overall effects of exposure
to water and possibly sunlight?  Pardon me for getting personal :-), but
if it is the effects of chlorine, might the effects actually be limited to
bleaching of a coloring agent?

> 2) What is it in Ultraswim that removes the chlorine, and how?

	According to the ingredient listing which follows, it is the
sodium thiosulfate.  There may also be some effect by the urea.

	While exposure to sodium thiosulfate will rapidly counteract the
effects of chlorine, I cannot see this process being *significantly*
better than simply using a conventional shampoo and plain water to wash
and rinse residual swimming pool water (with associated chemicals) from
the hair.

> I read somewhere once that citric acid reacts with chlorine.
> Lots of shampoos have citric acid, though, so if that is the "active
> ingredient" I'd as soon buy a cheaper one;  also, it's one of the
> last in the ingredient list, even after "fragrance."

	Under the circumstances found in a shampoo coming in contact with
chlorine in the form of hypochlorous acid in swimming pool water, there
will be no significant reaction between the citric acid and chlorine.
Citric acid serves another function, however, it that it acts as a
sequestering agent to inhibit the formation of "soap scum" when the shampoo
is used in hard water; i.e., the citric acid acts as a chelating agent for
calcium and magnesiun ions.

> These are the ingredients in Ultraswim:

	I'll briefly explain these ingredients...

> water
	We all know what this is. :-)  It probably accounts for over 90%
	of the composition of the shampoo.

> sodium laureth sulfate
	A surfactant which is responsible for the detergent and wetting agent
	actions of this shampoo.

> cocamide MEA
	A soap made from coconut oil and monoethanolamine (MEA), whose
	effects are enhanced by the sodium laureth sulfate above.

> urea
	This is probably claimed as a reducing agent to mitigate the effects
	of chlorine and hypochlorous acid.

> glycol stearate
	Ethylene glycol monostearate, which is probably used with the
	sodium hydroxide listed below to form an overall stabilizing
	oil-in-water emulsion, in addition to having some effects of a
	secondary soap.

> sodium thiosulfate
	A reducing agent which *definititely* combines with chlorine and
	hypochlorous acid to mitigate their effects.

> hydrolyzed animal protein (we all know about > that now! :-)
	Probably added to support a claim of "restoring lost protein" in
	hair.  Most likely ineffective (but not *provably* ineffective).
 
> DMDM hydantoin
	Beats me.  Maybe it's a "Secret Ingredient". :-)  Hydrolysis of
	hydantoin under certain conditions can be used to synthesize amino
	acids.
	
> methylparaben
	An antimicrobial agent used to preserve the product; yes, bacteria
	will grow on some soap and cosmetic products.

> fragrance
	So you smell "clean". :-)

> propylene glycol
	Probably used as a solvent to facilitate homogeneous blending of
	the ingredients.

> trisodium EDTA
	A sequestering and chelating agent used to inhibit formation of
	soap scum in hard water, and to dissolve any calcium salts should
	the swimming pool water be treated with HTH.

> diazolidinyl urea
	I have no idea what this substance is.  It may be an antimicrobial
	agent, or a dye, or a "Secret Ingredient". :-)

> propylparaben
	A fungicide used to preserve the product; yes, fungii and molds
	will grow on some soap and cosmetic products.

> sodium hydroxide
	Probably combines with the ethylene glycol monostearate above to
	form a stabilizing oil-in-water emulsion, at the same time
	forming a secondary soap.

> citric acid
	Used as a sequestering agent to inhibit formation of soap scum in
	hard water.

> sodium chloride
	Probably used to inhibit formation of water-in-oil emulsion as
	a result of mixing all of the above ingredients; probably improves
	"feel" of product.

<> Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp.
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