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Why is citric acid in shampoo and conditioner?

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I am doing research in my Chem 2 class on why certain chemicals are in household products and I was wondering if you could tell me why Citric Acid is in many shampoos and conditioners. If you could tell me it would be great. Thanks

Kasey S [last name deleted for privacy by Editor]
- Chesaning, Michigan

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Sorry, I don't know, Casey. Because it smells nice?

Ted Mooney, P.E. finishing.com Brick, New Jersey

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Citric Acid isn't used because of the smell. Fragrances are added for that purpose. It has a two fold reason for addition. Shampoos usually are at pH 5.5 because at slightly acidic pH the scales on a hair follicle lay flat making the hair feel smooth and look shiny. Citric acid is used to adjust the pH down to 5.5 (ish). It is a fairly weak acid which makes the adjustment easier. it also has a small amount of preservative action. Citric acid as opposed to any other acid will prevent bacterial growth. (I used to work in the lab for a cosmetics company)

Ciaron Murphy
Nordam Europe - Great Britain

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"I used to work in the lab for a cosmetics company"

It shows, Ciaron. Thanks for the great answer!

Ted Mooney, P.E. finishing.com Brick, New Jersey

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Well, Ted.. at least I found your comment humorous (ha, ha)

Marc Green anodizer - Boise, Idaho

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Hey thanxs for the great answer! It really helped me on my science fair project!

Rebecca [last name deleted for privacy by Editor]
- NLR, California

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wow...thx for the info, but what is pH 5.5?

Pat [last name deleted for privacy by Editor]
- Gaithersburg, Maryland

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The full definition of pH is: "the negative antilog of the hydronium ion concentration", but that information may be beyond your grade level, Pat. The easiest way to look at it is that a pH of 0 is as acidic as you can get, a pH of 14 is as alkaline as you can get, and a pH of 7 is neutral.

Again, depending on your grade level, you may or may not have a concept of what a logarithmic scale is, so you might be able to understand a little more. In a logarithmic scale you "count the zeroes".

So a pH of 5.5 is slightly acidic, but it's less acidic than a pH of 5.0. And in turn, a pH of 5.0 is only one-tenth as acidic as a pH of 4.0, only one-hundreth as acidic as 3.0, only a thousandth as acidic as 2.0, etc.

Ted Mooney, P.E. finishing.com Brick, New Jersey

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Hiya. I'm 10 and 27 of us kids (and 1 teacher) want to know whether shampoo is an acid, base or neutral. I'm in Grade 6.

Christopher J.
I'm just in Grade 6! - Bundaberg, Qld, Australia

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Ciaron Murphy already answered this question pretty clearly on this very page, Christopher. If it wasn't clear enough in some way, please rephrase your question in terms of the answer that was already given. Thanks.

Ted Mooney, P.E. finishing.com Brick, New Jersey

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March 18, 2008

Thanks for the help everyone it really helped me on my E.C. health homework. I was just wondering if: citric acid is in bath and body volumizing shampoo?

Tom B [last name deleted for privacy by Editor]
homework - St. Paul, Minnesota

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June 19, 2008

Most shampoos that we use everyday are acidic while conditioners are alkaline. Why these shampoos and conditioners are manufactured to be acidic and alkaline respectively? What are the benefits to hair care? Can u please also enlighten me on how 2-in-1 shampoos work? Thanks you!

Wei L [last name deleted for privacy by Editor]
student - Singapore

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October 6, 2008

What pH should shampoo & conditioner have?

Sarah W.
student - England

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Hi, Sarah. Half of that answer is already on this page. Please phrase your question in terms of what has already been said so that we can move forward.

Regards,

Ted Mooney, P.E. finishing.com Brick, New Jersey

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February 19, 2010 Hi, I am Trina, Manager, of a Boutique in Williams Lake, B.C We sell a mild detergent called 'Forever New', (citric base). It prevents the elasticity in under garments from breaking down. I have had no complaints with this product, though I have had one customer enquire about it, because she has had a reaction to one of two products she is using in her home. I have been helping her with new information, and am trying to get a little bit more :) Any suggestions would be very beneficial for myself and my customers. Thank-you Very Much Kind Regards Trina Trina Casler supervisor sales associate - Williams Lake, B.C., Canada February , 2010

Hi, Trina.. Citric-based means based on citric acid, which is an acid in citrus fruits. But chemical formulations are complex. You should probably ask the manufacturer for the MSDS for this product (material safety data sheet) and pass that on to your customer. Good luck.

Regards,

Ted Mooney, P.E. finishing.com Brick, New Jersey