Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Why is citric acid in shampoo and conditioner?
Q. 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 [surname deleted for privacy by Editor]- Chesaning, Michigan
2000
A. 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 MurphyNordam Europe - Great Britain
2000
on AbeBooks
or Amazon
(affil links)
"I used to work in the lab for a cosmetics company"
It shows, Ciaron. Thanks for the great answer!
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
!! Hey thanks for the great answer! It really helped me on my science fair project!
Rebecca [surname deleted for privacy by Editor]- NLR, California
2004
Q. Wow...Thanks for the info, but what is pH 5.5?
Pat [surname deleted for privacy by Editor]- Gaithersburg, Maryland
2004
A. The full definition of pH is: "the negative antiloglog of the hydronium ion concentration", but I don't know if that wording is beyond your grade level, Pat. The easy 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 get, and a pH of 7 is neutral.
Depending on what grade you're in, you may or may not have been taught logarithmic scales. In a logarithmic scale you "count the zeroes". So your 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-hundredth as acidic as 3.0, only a thousandth as acidic as 2.0, etc. Good luck!
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2004
@ Ted Mooney, P.E. RET
First of all...
"The full definition of pH is: 'the negative antilog of the hydronium ion concentration' ".
WRONG!!! Clearly this is a bit "beyond your grade level" but pH=-log[H+](base 10 of course), just negative log, not antilog.
Secondly,
"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"
ALSO WRONG, I'm guess you don't even know what a logarithm is based on that explanation, extremely acidic solutions can have a negative pH, and similarly extremely alkaline solutions can have pH's above 14, some hair care products used in salons get as high as pH=17.
I appreciate the sentiment trying to help this kid out but check your facts.
Cal State Univ. Chico - Chico, California, USA
Thanks T.J.
You're right that pH is the negative log, not the negative antilog; thanks for correcting a silly mind-slip.
Kids from 3rd grade come to this site, and so do post-docs who are way beyond my level; but we often don't know who's who, and there are a hundred readers for every poster anyway. So starting with "depending on your grade level" seemed a good way to avoid patronizing people. On the other hand your use of "beyond your grade level" was deliberately insulting. You certainly realize that a P.E. knows what logarithms are, so ask yourself why you would publicly post that?
For 23 years now we've worked hard to make this site "... a place of camaraderie ... offering a friendly, welcoming atmosphere ...striving to live aloha". So I'd appreciate if you saved ALL CAP, multiple exclamation point, snide comments for your Youtube and Facebook postings. Pat and I aren't the only ones in this conversation who still have something to learn.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. Hiya. I'm 10 years old, 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
2007
A. Ciaron Murphy already answered this question on this page, Christopher. If it wasn't clear enough, please rephrase your question in terms of the answer that he already gave, so that you can feel comfortable that you used this site to learn, not to ask someone to post an answer to cut & paste for your homework ? Thanks!
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007
Q. 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 [surname deleted for privacy by Editor]homework - St. Paul, Minnesota
March 18, 2008
Why is shampoo acidic and conditioner alkaline?
Q. Most shampoos that we use everyday are acidic while conditioners are alkaline. Why are these shampoos and conditioners manufactured to be acidic and alkaline respectively? What are the benefits to hair care? Can you please also enlighten me on how 2-in-1 shampoos work? Thank you!
Wei L [surname deleted for privacy by Editor]student - Singapore
June 19, 2008
What is right pH for shampoo?
Q. What pH should shampoo & conditioner have?
Sarah W.student - England
October 6, 2008
A. Hi, Sarah. Half of that answer is on this page already. Please try your best to phrase your question in terms of what has already been said so that we can keep moving forward. Thank you.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. 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
supervisor sales associate - Williams Lake, B.C., Canada
February 19, 2010
A. 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.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February , 2010
Q. Hello,
I'm venturing into the world of homemade hair care and I'm trying to make a coconut oil based conditioner (along with neem oil, tea tree, rosemary & lavender essential oils) that rinses out well and doesn't leave hair oily. We have very fine hair and oily scalps so this is definitely an issue. Would adding citric acid to my recipe help with this? I know there are many other oils I could use, but the coconut oil is particularly important because it helps deter lice (something that's a big problem in this area and I want to be preventative). Thanks so much!
- Bainbridge, Pennsylvania, USA
September 22, 2012
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