Gee, Your Hair Smells Terrific! Why? You might not want to know.
?This is Sandra Tsing Loh with the Loh Down on Science, wondering how to put this delicately.
?Okay. For centuries, people all around the world have used urine for cleaning. An oxymoron? No, sound chemistry!
When urine's fresh, it’s acidic, but over time it ferments and becomes alkaline, like soap. That lets it cut through oil and grease.
?Even today, some use urine for shampoo--they say it makes their hair soft and manageable. It can even prepare hair for dye. The urea in it moisturizes, countering dye’s drying effects.
Consider that women in ancient Rome used mare’s urine, lemon juice, and olive oil to dye hair red. And in Renaissance Europe, a blend of urine, ashes, and dye turned hair blond!
?Sure, the smell can be a tad off-putting, but it rinses out cleanly. Heck, you’re using it anyway. Urea is already found in modern cosmetics, moisturizers, and soaps!
A man-made version, anyway. At least that’s what the research says: man made urea. That’s all and . . . have a great day!
<em>The Loh Down on Science</em> is produced by LDOS Media Lab, with 89.3 KPCC Pasadena, California. And made possible by the generous support of the Gordon and Betty Moore Foundation.