Dear Straight Dope:
What's the deal with advertisements for soap claiming the stuff is "pH balanced"? My knowledge of chemistry may leave something to be desired, but if the pH was out of balance, wouldn't you either burn your skin or have it slough off if it were too far in the other direction? I'm afraid to bathe until I receive an answer.
Jim Cleary, Itasca, IL
There’s balance and there’s balance, Jim. The pH of a soap is a measure of its acidity. Soap tends to be basic (the opposite of acid). Balanced-pH advocates say the natural chemicals on your skin form a slightly acidic protective barrier, and that a too-basic soap will destroy this barrier and lead to irritation of the skin. (Click here for a clear if somewhat irregularly spelled discussion of the topic.) Thus a pH-balanced (neutral) or slightly acidic soap is easier on your skin.
Assuming you buy all this (chemists tend to be skeptical, but what do they know?), the question is whether soaps that AREN’T advertised as “pH-balanced” are sufficiently out of balance that they will cause your skin to burn, slough off, etc. One assumes such fears are groundless. How often do you hear about people going to the emergency room for soap burns? Still … one never knows, does one? Maybe we SHOULD be careful to use only “pH balanced” soap. Maybe, in fact, if we don’t use pH balanced soap, our skin will soon be covered with horrible leprous sores and we’ll be ashamed to ever appear in public again! GODDAMIT, GIMME THAT SOAP!!!
Any more questions?
Send questions to Cecil via firstname.lastname@example.org.
STAFF REPORTS ARE WRITTEN BY THE STRAIGHT DOPE SCIENCE ADVISORY BOARD, CECIL'S ONLINE AUXILIARY. THOUGH THE SDSAB DOES ITS BEST, THESE COLUMNS ARE EDITED BY ED ZOTTI, NOT CECIL, SO ACCURACYWISE YOU'D BETTER KEEP YOUR FINGERS CROSSED.