Old Myth Busted: There are not numbing agents in J&J Baby Shampoo! I had heard this and thought it sounded strange so I investigated. The belief as to how this myth started, according to The Beauty Brains, was because of an ingredient, "benzyl alcohol", that is believed to have been used as a preservative. It's not used in J&J Baby Shampoo anymore though. The reason this shampoo doesn't make babies cry is because of the size of micelles (these are electrically charged particles formed by accumulations of molecules). Smaller micelles can penetrate the eye and irritate it, where as larger ones, like in baby shampoo, can't penetrate and therefore don't irritate eyes. Salt content, pH and impurities are all important factors in making things tear-free as well.
Image: Google Images
References: The Beauty Brains
Image: Google Images
References: The Beauty Brains