Talk:Shampoo

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page organization[edit]

Shouldn't the composition section and the ingredients sections be merged? DrPD (talk) 01:48, 1 February 2010 (UTC)

etymology?[edit]

Wouldn't it make sense to include some history of the word, or would that be redundant because it's already in the Wiktionary? 70.5.3.238 (talk) 04:52, 28 May 2008 (UTC)

History[edit]

The article does not really give the history of shampoo in the sense of saying when it was discovered/invented in Bengal, how it was made or first used, etc. It simply states that Deen Mahomet introduced it to Britain. If the pre-British history of shampoo is not known, perhaps a statement to this effect should be made?

According to http://www.indianmuslims.info/book/export/html/183, by the time Deen Mahomet moved to London to market curry and shampoo, he had been a Christian for over 20 years. Although his parents were Muslims, the family lived Bihar, which was predominantly Hindu, and also had large Buddhist, Sikh and Jain minorities. It is therefore not correct to associate the invention of shampoo with Islam (or with any other single religion) unless the individual/community that first discovered it can be positively identified.Grace has Victory (talk) 00:38, 30 October 2012 (UTC)

Too UK-centric, it has not a single mention of the history of hair washing before it was introduced into UK. --Japoniano (talk) 16:29, 13 May 2014 (UTC)

urban legend/toxicity[edit]

There are no references to claims that Sodium dodecyl sulfate is carcinogenic. Though the SDS page there is reference to the urban legend. I think that clean up crews have been overzealous in removing claims of this sort that are not well supported. People come to wikipedia for perspective, not just lists of links to what is elsewhere. Explaining the chemistry/toxicity issues or linking to where they are explained with links that someone who doesn't already know the connection... that is what this article needs to do better. The social context is erased when all we write about are scientific facts about materials instead of also including ideas that require more difficult referencing. Sorry to sound so negative here but I am seeing this issue in too many articles these days.Rusl 23:26, 2 August 2007 (UTC)

Is there anyone who knows about the basic chemical differences about shampoos that claim to be a volumizer, clarifying, dry vs oily, and about a million other types? In a side note, some shampoos have hair dyes and toners in them to subtly maintain or change the color of your hair. For example, some people use purple based shampoos to make their hair less brassy and yellow (many blondes use this to make the hair white). This is rumored to be where the term blue haired lady comes from when older women leave this in their hair to long to tone they're gray. Shouldn't this be written somewhere with a description?

Short answer: There is no real difference between those shampoos. Longer answer: Marketing claims and chemistry can be found at the sites of companies that sell shampoo ingredients. Try:(http://www.ispcorp.com/) Even longer answer: A book could be written on this subject. In fact, some have been written. The unfortunate problem is that much of this information isn't published anywhere on the web. Since it's not published, it can't be cited. If it can't be cited, it has no place in Wikipedia. Sorry, but that's the catch-22 here.Bobzchemist 16:30, 11 January 2007 (UTC)



The accurate answer: there are substantial differences chemically between soap, detergent and shampoo. Read any standard organic chemistry text for the details. pH plays a huge part. There are differences between people and species with respect to the chemistry of hair and skin. Whether or not a shampoo is antibacterial can also impact on the normal flora of the skin. An organic chemist and a dermatologist can elucidate these factors here. — Preceding unsigned comment added by Drjude518 (talkcontribs) 17:04, 31 December 2013 (UTC)



Medium Answer, the basic ingredients are typically the same, however, the ratios and blends do vary within bands so that various characteristics are optimised. If you follow the ispcorp link, you'll find additives for volumising for instance. Unfortunately the bible of the cosmetics industry, Harry's Cosmetology isn't to my knowledge, online (Prehaps google books has excerpts), so you may need to get to a large library to read it Valueaddedwater (talk) 22:51, 28 April 2008 (UTC)

SOURCES DON'T NEED TO BE ONLINE! Provided it has been published _somewhere_ - in a book, an academic or industry journal, even a newspaper - it can be cited. Harry's Cosmetology should be a perfectly valid source (and as an aside, if it's the 'Bible' of cosmetics it should have its own Wikipedia article)131.111.245.195 (talk) 23:54, 21 February 2009 (UTC)

htf do youmake homemade shampoo. i wanna know cause i'm kinda poor. thanks to anyone who can help.


I, too, would like to know, if anyone has the answer. I think it's made from lye and fat or something though.

All shompoos are made from Synthetic Detergents, these days. Short Answer: Use bath soap. Longer answer: It is not possible to save money by making your own. You will pay more for the ingredients than you will for the finished shampoo. Buy the cheapest generic stuff you can find, it will work 90% as good as the most expensive shampoo on the market.Bobzchemist 20:29, 24 October 2005 (UTC)

There are brands of shampoo that are extremely inexpensive. Go to a dollar store. I do not believe you can purchase the necessary chemicals to make your own shampoo. If you have ever washed your hair with soap you'll understand why - they have to use cleaners that do not strip out the necessary oils. When this happens, your scalp produces oil faster, your hair becomes much more succeptible to breakage, splitting and fraying, and it is almost instantly unmanageable. The detergents used in shampoo have to balance things out, rather than stripping them out. I suppose an alternative is to go with dreads. JMPZ 05:17, 24 April 2006 (UTC) Using bar soap to wash hair is possible, but not desirable, mainly because the pH of an average soap bar made from saponification of fats/oils with lye (Sodium Hydroxide) is quite high at around pH 10 or therabouts. This causes the scales on the hair shaft to fluff out giving a higher risk of felting or interdigitation. If you rinse afterwards with something acidic like lemon juice or vinegar, you may well get away with it, but TBH with cheap own label shampoo available its not really worth it. Use a cheap shampoo or shower gel instead 20:31, 30 September 2007 (UTC)


  • Moved this question to the talkback (obiously) "Does anybody know when the word "shampoo" came into the English language?"

First sentence is: "A shampoo is a traditional Indian and Persian body massage given after pouring warm water over the body and rubbing it with extracts from herbs. It can be used in conjunction with a conditioner for optimal results, but it is not a necessity."

Conditioners are relevant to Indian and Persian body massage? Otherwise we're getting confused here.


"Shampoo is also available in solid form, allowing it to be rubbed onto the hair. This has the advantage of having the shampoo easily carried, but also has the disadvantage of working less efficiently on longer hair."

What is "having the shampoo easily carried" intended to mean? That the shampoo can easily be carried when travelling? That it can easily be spread in the hair? --Brolin Empey 23:55, 2005 August 2 (UTC)

I believe that the "solid" shampoo subcategory is actually a subtle advertisement. I was only able to find one company manufacturing it. I'm calling it non-notable, and I will delete it unless someone objects and can show a citation from more than one company. Bobzchemist 21:17, 9 February 2007 (UTC)

There have been various commercial solid shampoos going back at least to Neutrogena Solid Soap Shampoo ca. 1970. (That's not counting soaps which were labeled as for shampooing among other uses, e.g. "Lifebuoy Shower, Bath and Shampoo Soap", as it was called for a while.) There are also recipes for homemade shampoo bars at soapmaking sites. There was a brand of shampoo bar from Fla. a few years ago and since discontinued based on disodium lauryl sulfosuccinate. If somebody cited brands now, those would be advertisements. --robgood@bestweb.net216.179.1.232 (talk) 22:55, 24 March 2009 (UTC)

Shampoos, Conditioners, and Pro-vitamins[edit]

A lot of hair care products are adversted as containing 'Pro-Vitamins'. My understanding was that a pro-vitamin was something the body (usually the liver) could convert into a vitamin when required. For example, betacarotene would be considered 'pro-vitamin A.

Is there any benefit in adding 'pro-vitamins' to hair care products, or is this just impressive-sounding marketing hype? Are there any good refernces on this subject? --PJF (talk) 04:23, 27 Feb 2005 (UTC)

  • Check out the entry Panthenol, which is a pro-vitamin of B5. Consider that hair is dead cells, so there is no bioactivity for any vitamin additive. However, some vitamins, like Panthenol and Vitamin E, do have a cosmetic effect. I think the understood benefit (or at least the most widely marketed benefit) is that it plumps the hair shaft by as much as 10%.

Panthenol does have an ability to bind electrostatically to the hair shaft to give a conditioning effect that can be percieved by the user in the same way that quaternery based conditioners (The same as used in fabric softener)do. If anyone says that they are "Feeding the hair" this is guff, as the hair shaft is dead (Only the bulb under the skin is actually alive). Rememeber that this is a cosmetic product, so the only effects you will get are, by definition, cosmetic Valueaddedwater 20:35, 30 September 2007 (UTC)

Waterless Shampoos[edit]

Does anyone have any information about waterless shampoos? Like how they work and their main ingedients that make it so.

So-called "Waterless" or rinse-free shampoos are simply much more dilute versions of "regular" shampoos. They work exactly the same way as regular shampoos do.Bobzchemist 06:07, 18 February 2007 (UTC)

Another version of the waterless shampoo is an absorbent powder such as Talc or cornstarch, which is rubbed through to remove excess grease and oil. They're not popular as they are messy, don't always brush out clean, and are of limited effectiveness. Valueaddedwater 20:38, 30 September 2007 (UTC)

Cleanup[edit]

I marked this article for cleanup because it was generally terrible. There was much POV ranting about natural shampoos without the harmful detergents... you know, the ones that actually clean your hair in the first place :

so I rewrote a bit, commented out some crap, and am working on trying to add some more information

Big clean up underway[edit]

I cleaned up a lot of the ranting. The previous guy had a problem with the shampoo industry, I think this article should cover:

  • History
  • How It Works (generally)
  • The Chemistry
  • Natural Shampoos
  • Two-in-One Shampoo and Conditioner
  • The Shampoo Industry (have a section critical of industry?)
  • Brands
  • References

Feel free to clean up my work, this is not my expertise. —Preceding unsigned comment added by Eddie tejeda (talkcontribs)

synthetic detergent[edit]

I'm curious as to the source of saying the detergents/surfactants used in modern shampoo are considered to be synthetic? How do you define whether its a natural or synthetic surfactant? —Preceding unsigned comment added by Darconas (talkcontribs)

All detergents are synthetic, but they are called synthetic to differentiate them from soaps, which are made from animal or vegetable fat.Bobzchemist 06:10, 18 February 2007 (UTC)


Two-in-One Shampoos[edit]

I agree with the unsigned poster above: the chemistry behind two-in-one shampoos (of which there seem to be more than one kind, see [1], [2]) should be covered here in detail. -- Karada 14:58, 31 March 2006 (UTC)

No Vandalism[edit]

Isn't kind of strange that so far there has been no vandalism to the page 64.12.116.5


No I'm pretty Sure that's a good thing.

Purpose[edit]

I remember learning that the purpose of shampoo was to clean the scalp, not hair. This is the reason why you are supposed to massage the shampoo into your head, to clean all the dead skin cells. 71.250.19.117 13:21, 14 April 2006 (UTC)

Dimethicone[edit]

I removed the Dimethicone section from the Ingredients heading, as Dimethicone is used in conditioners and there is a separate article about that. Carax 04:51, 16 April 2006 (UTC)

When was modern shampoo invented?[edit]

I was watching the Channel 4/PBS documentary "1900 House" DVD and they claim that shampoo as we know it was invented in 1950 (!) -- which seems incredibly late. As this Wiki entry states, shaved soap and hot water passed for hair washing for quite some time. The particpants in 1900 House made shampoo according to period recipes but complained it was nothing like what we know as shampoo (as it left quite a bit of residue and left the hair in terrible condition). (They later tried another period recipe containing only egg yolks and lemon! yuck!)

Does anyone have any history on modern shampoo? Certainly movie stars in the 1940s would not have used dissolved soap shavings, would they? Modern shampoo would have to be linked with the creation of sodium lauryl sulfate. Navstar 18:40, 8 June 2006 (UTC)

Synthetic detergents started to be commercially available in the 1930's. So a 1940's screen star would have had the luxury, a silent movie star wouldn't have been so luckyValueaddedwater (talk) 18:59, 29 April 2008 (UTC)

Protein/Animo Acid section[edit]

I agree amino acids and nucleic acis would provide very little benefit to hair. And whole protein molecules would be too large to enter the cuticle. But the section seems to want to argue about *permanently* bonding new amino acids to hair, which of course isn't going to happen in dead cells. But I haven't seen any conditioner or shampoo marketed as permanently improving hair. Adding hydrolized protein bits that are cationically charged will help temporarily improve the look of damaged or fine fine (until its washed again). --68.103.154.140 17:04, 27 June 2006 (UTC)

an opposing view[edit]

is it really good at all to use? has the details ... I would love to see this content cited, as well as rebutted in the content of this article.

I spotted 3 basic chemical errors in the first paragraph of that link. Its not, shall we say, wikipedia standard as regards a) accuracy, or b) POV Valueaddedwater (talk) 19:06, 29 April 2008 (UTC)

natural vs. organic[edit]

can somebody put in a little snippet about natural vs. organic? to the best of my knowledge, organic is a term used by the FDA and hence, there is no such thing as an organic shampoo (or at least it is in washington state)

i dont want to do it at the risk of sounding like a 12 year old's run on sentence, but from working in a salon, i can give you this link that very breifly covers it [3]

ps, thanks to whoever deleted the whole section about different brands. considering theres thousands upon thousands, that wouldve been an effort in vain...

Hazzayoungn 10:05, 23 December 2006 (UTC)

Requires more points of view.[edit]

I think this article lacks criticism. There are alot of shampoos which actually is hazardous to either/both the environment or/and humans in either small or big ways.

PS: This line sounds like commercial to me.

Feel free to write a section on the controversey. Personally, I feel that the above statement has no basis in fact. There are many people that make this claim - they all turn out to be selling something.Bobzchemist 03:58, 16 January 2007 (UTC)

The biodegradeability issue hasn't been relevant since the 60's when the use of phosphate based, non biodegradeable detergents was banned, due to the outflow of sewage works being a wall of foam. Microbial preservation of liquid detergent products is always an issue, so once it has been used by the consumer, and hits the sewers, its bug food Valueaddedwater 20:43, 30 September 2007 (UTC)



Shampoo formulations seek to maximize the following qualities:

  • Easy rinsing
  • Good finish after washing hair
  • Minimal skin/eye irritation
  • No damage to hair
  • Feels thick and/or creamy
  • Smells good
  • Low toxicity
  • Good biodegradability
  • slightly acidic pH, since a basic environment weakens the hair by breaking the disulfide bonds in hair keratin.

Many shampoos are pearlescent. This effect is achieved by addition of tiny flakes of suitable materials, eg. glycol distearate (a wax).


62.16.202.221 01:19, 16 January 2007 (UTC)

Waterless Shampoos[edit]

…like those used for pets. What exactly are these? —Nahum Reduta 12:00, 14 April 2007 (UTC)

Trivia[edit]

This section seems pretty useless.

Shamoo triva - now I've heard everything! Think outside the box 14:05, 18 May 2007 (UTC)

Soap versus Shampoo[edit]

Hi:

I think the article could also address shampoo as a class of soap. My understanding is that shampoo is a soap with a different vehicle, but it's basically a soap. Ie washing your hair with a bar of soap is no different.

(Signed a man with a beard whose idiot friend gave him very expensive shaving soap for his birthday -- WTF?)

Both shampoo and a true soap are detergents, but thats where the similarity ends.

Using soap to shave with is not the same as washing hair with it, as it doesn't matter if the hair above the skin surface is damaged before shaving, as you're cutting it off anyway.

If you are into the yul brinner look, I suppose washing your scalp with a bar of soap would be similar Valueaddedwater 20:47, 30 September 2007 (UTC)

Haha you are ridicioulas. It is diffirent.

--78.149.175.76 (talk) 17:14, 12 January 2008 (UTC)

shampoo's bad for your hair. It cleans out dirt, but also the oil that makes your hair shiny and strong. However shampoo's sold as something your hair really needs, and the truth is suppressed. There are several common sorts of soapy things. They attract oils by electric charge, allowing the oil to be emulsified with the water. For some reason, these cleaners are themselves made from fats. Soap is made from animal or vegetable oil, and detergent is made from mineral oil. Detergents can be made more powerful. Shampoo is detergent, just like dishwashing detergent, bathroom cleaner, and engine block cleaner.
People used to use soap to wash their hair, as well as their dishes, clothes and bathrooms (and horses, before there were engines.) Soap was better suited to washing hair, because it didn't remove so much of the oils that are naturally in hair.
But the water supply slowly changed. It's now generally more alkaline, which people call hard water. When this started happening, soap didn't work so well. The chemicals which make water alkaline make soap stop lathering well, and form insoluble scum (eg. the ring in the bath.) So soap got less and less effective for all its cleaning uses. I guess the water was always pretty alkaline in some places, so soap was never an ideal cleaner. Around the beginning of the twentieth century, household detergents became available. Detergents have no problem with alkaline water, so they were really popular. They soon became cheaper than soap, too.
So that's why people stopped using soap for almost everything, and started using detergents. Detergents are excellent cleaners for most uses. If you've tried using soap to wash your hair, you probably know how your hair goes all rough and tangly. This is worse if your water's harder (more alkaline.) I moved recently, and suddenly started having problems using soap in my hair. The problem is that hair reacts to acids and alkalis. Each hair has little scales, like scales on a snake or shingles on a roof. Acid makes the scales lie down flat, which makes your hair shiny and smooth. (Ever heard that lemon juice is good for your hair?) Alkali makes the scales stand up, which makes your hair look dull and feel rough and tangly. Therefore hard water, which is common these days, makes it harder to wash your hair. If you use soap to wash your hair in hard water, then the combination of your hair's scales standing up and the soap forming scum makes your hair into a terrible mess. Then, since your hair's all tangled and rough, it's impossible to rinse out all the soap, which makes it look terrible.
Shampoo, being detergent, can rinse out of your hair fine even in alkaline water. That's its only good point. Its fundamental, but covered up, bad point is that it's very harsh, and damages your hair permanently. Conditioner was soon introduced as people noticed that shampoo sucked the oils out of their hair dry and left it all dry and brittle. Conditioner puts artificial oils in your hair, and they stay there just long enough so that you don't associate the damage to your hair with the shampoo that caused it.
You have to wash your hair every day, not because it always gets dirty so fast but because the oils from the conditioner don't last and have to be replenished. Conditioner wasn't used until shampoo came about.
But the real cheat in shampoo is when it's sold as being especially good for your hair. Expensive shampoos are in a way better, but only because the conditioner that comes with them is better at covering up the damage done by the shampoo. The actual shampoo itself is pretty much the same as any cheap shampoo. The professional formula, which will nourish your hair and make it grow more healthy, with vitamins and natural nutrients, gentle seaweed extracts, jojoba oil…
Remember that your hair's dead. That exposes half of shampoo advertising as lies. Remember that shampoo is just detergent. That shows that most of the remaining half is lies too. Remember that the oils your hair needs come naturally out of your scalp, as they've been doing for thousands of years before conditioner was invented. When you think about it, nothing that is claimed about shampoo and conditioner is true.
In a way, we really do need conditioner, as advertising implies. But the real reason why we need it is because our hair gets damaged by shampoo. This is just another case of using lies to help a bad product (shampoo) gain dominance over a good product (soap), then introducing another product (conditioner) to compensate for the bad product's faults, and then tricking people into accepting huge price increases once they forget the good product.
The only good thing about shampoo is that it doesn't work any worse in hard water.Does that ever get mentioned in advertising? The rest is lies, to fool you into paying $10 for a $1 bottle of perfumed detergent. Soap is good to wash your hair with. Forget all the dregs of misinformation spread by shampoo manufacturers, and forget that soap is "harsh". Remember that the problem with using soap is in the water, not the soap. You just need to solve the problem of the hard water, and soap is fine to use. I can recommend two ways.
If your water's not too hard, just substitute soap for shampoo, and use any old cheapish conditioner. The conditioner will make the scales on your hair lie down, and let the last of the soap get rinsed out. You might have to experiment with different soaps and conditioners. Maybe some conditioner which is pH balanced is best. Some "good ol" plain soap with no added water and perfume is probably best.
Otherwise, you can add some weak acid at some point in the washing process. Since you need just a tiny amount, even cheap vinegar will do, without leaving a smell. You could make a soap goo out of soap and water, and add a bit of lemon juice. You could have a jug of water with a teaspoonful of vinegar in it, to rinse your hair with after soaping. Or how about pouring it into a plastic squirty bottle, so you don't spill it. Another good thing is oil of rosemary. It stimulates your scalp, to encourage the natural oils to flow. Actually I haven't worked out how to get it onto my scalp, since there's all that hair in the way, but I've heard it's possible.
So in summary, shampoo had a legitimate claim as an alternative for soap. But now it's not sold by that claim, it's sold by lies. Soap's better for your hair, and you can still use it if you compensate for hard water. If you only have hard water, then use any old conditioner along with soap. Like most soaps, shampoo removes the 'good stuff' from your hair, just like soap removes 'the good stuff' from your skin that fights bacteria or is otherwise considered 'good' bacteria the skin naturally produces to stay healthy..........
Perhaps some of this can be mentioned in the article? The Unbeholden (talk) 04:24, 7 April 2010 (UTC)

general[edit]

I deleted the "surfactants" section, which was entirely redundant with the internally linked article. Some wise guy had added "phattionic" to the list, heh, heh. 216.179.1.227 06:09, 25 October 2007 (UTC)robgood@bestweb.net

Response to a previous question...[edit]

Homemade shampoos are better for your hair and much cheaper.

http://www.naturalfamilyonline.com/go/index.php/389/why-you-should-go-no-poo/

That's actually better to use seeing as it won't damage your hair at all, unlike shampoo. Disastrous Catastrophe 12:18, 30 October 2007 (UTC)DisasCatas

Is it true...[edit]

that cow urine can be used as shampoo and in parts of africa people are actually showering in piss? —Preceding unsigned comment added by 79.118.182.221 (talk) 10:48, 4 July 2008 (UTC)

External reference: Boys washing hair in cow urine. -- MarkAHershberger(talk) 12:02, 6 December 2011 (UTC)

can i as the history of shampoo in chronological date? —Preceding unsigned comment added by 124.107.158.75 (talk) 09:19, 23 July 2008 (UTC)

New User Wants to Add a Subsection to Section[edit]

Solid[edit]

Solid shampoos or shampoo bars use as their surfactants soaps and/or other surfactants conveniently formulated as solids. They have the advantage of being spill-proof, and the disadvantage of being slowly applied, needing to be dissolved in use.

Mens/Womens Brands[edit]

Does anyone know what the difference is, apart from scent, between these two types of shampoo? A friend asked me recently, and I was surprised that Wikipedia didn't mention it. TheDarkFlame (talk) 01:53, 20 March 2009 (UTC)

Animal Shampoo -- sources?[edit]

I removed the section about animals skin being thinner than humans and thus requiring milder shampoos because while quite possibly true, it wasn't sourced.

This section is terribly organized and should be arranged into coherent paragraphs. —Preceding unsigned comment added by 67.243.140.144 (talk) 06:21, 14 July 2010 (UTC)

The animal shampoo section claims that differences in skin structure require special shampoo formulations for animals. This seems unlikely to be true and requires a reference.DrPD (talk) 01:55, 1 February 2010 (UTC)

Shampoo Free?[edit]

I'm wondering if the shampoo free ("no poo") movement might not merit some inclusion in this article along with other criticisms of shampoo.

By way of proof of notability/verifiability, I offer the following: this from the Boston Phoenix and this article from Salon.com. There are more out there, but these seem to be the most Wikipedia ... friendly. 70.94.242.178 (talk) 06:45, 27 February 2010 (UTC)

External Links[edit]

I could be wrong, but doesn't it look like advertisement to anyone else? —Preceding unsigned comment added by 74.58.75.211 (talk) 03:27, 18 April 2010 (UTC)

beijinhos mae :) — Preceding unsigned comment added by 188.140.35.61 (talk) 12:15, 7 December 2011 (UTC)

Theory section: dubious use of reference[edit]

NASA and Soviet studies on hygiene in preparation for space station missions do not support this conclusion,[28] and no mechanism of action for how the sebaceous glands below the skin detect sebum levels in hair has been proposed.

Fn28 links to ch10 of Packing for Mars. But the book in ch10 states:

> Once a set of clothes becomes saturated and oil starts to build up on the skin, what’s the end point? Does uncleansed skin grow ever greasier as the days pass? It does not. According to the Soviet research, the skin halts its production of sebum* after five to seven days of not bathing and not changing one’s increasingly well-greased clothing. Only when the person changes his shirt or takes a shower do the sebaceous glands get back to work. Skin seems happiest with a five-day buildup of oils. Listen to Professor Elaine Larson, editor of the American Journal of Infection Control, talking about the stratum corneum, the outermost layer of human skin: “This horny layer has been compared to a wall of bricks (corneocytes) and mortar (lipids)” and helps “maintain the hydration, pliability, and barrier effectiveness of the skin.”

This seems to say the exact opposite of what the article text is claiming Roach wrote in her book. Could someone clarify this? --Gwern (contribs) 01:58 3 May 2013 (GMT)

If no one can explain what part of the book supports the claims the article is making, perhaps it should be removed. --Gwern (contribs) 02:14 6 May 2013 (GMT)