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Consumer Products

Periodic graphics: Soap versus body wash

Chemical educator and Compound Interest blogger Andy Brunning explains the similarities and differences between the two bath products

by Andy Brunning
May 14, 2018 | APPEARED IN VOLUME 96, ISSUE 20


Credit: Andy Brunning
Credit: Andy Brunning
Credit: Andy Brunning

To download a pdf of this article, visit

References used to create this graphic:

Cosmetic formulations: Body wash

Soaps and detergents

Make your own soap! Part 1: The chemistry behind soap making


Skin pH: From basic science to basic skin care

Effect of detergents on skin pH and its consequences

A collaboration between C&EN and Andy Brunning, author of the popular graphics blog Compound Interest

To see more of Brunning’s work, go to To see all of C&EN’s Periodic Graphics, visit

This article has been translated into Spanish by and can be found here.



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Kevin Kolack (May 14, 2018 3:47 PM)
Love Andy's work, but I think this is a bit oversimplified and perhaps misleading. Sodium and potassium stearate have nearly identical melting points. Liquid soaps are liquids because soaps are lyotropic liquid crystals and body washes contain more water than bar soaps. This is also the cause of the pearlescent nature of many liquid soaps. Soak a bar of soap in a bunch of water, and presto, you've made liquid soap. In the right-hand column, calling the main ingredient of a body wash what it is, a detergent, would be a useful note to the public.
Andy Brunning (May 21, 2018 7:00 AM)
Hi Kevin, thanks for the feedback. As I'm sure you can understand, the space available for these graphics means we have to be a bit selective about the information included. In this case, we decided to include the fact that sodium hydroxide is used in the manufacture of solid soaps, while potassium hydroxide is used to manufacture liquid soaps. As there's no further discussion of liquid soaps in the graphic, detail on the various other differences was not included.

Similarly, in the right-hand column discussing body washes, we decided to stick to the term already defined in the graphic, surfactants, rather than introduce additional terms that would also require definition.
Alex Prevatte (May 16, 2018 3:59 PM)
Which one is better then????????????????????????????????????????????????????????????????????????????

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