Most of what’s in shampoo does nothing to cleanse—instead, it “strokes your emotions,” writes Bill Bunn in Salon. If your hair is greasy, you simply need detergent. But shampoos contain a variety of other ingredients—two-thirds by volume—intended to make you feel good about the product and use more than you need to do the job. Take thickeners, for example: “Shampooers trust the velvet heft of the shampoo in the palms of their hands,” so several ingredients simply make the soap thicker.
These extra ingredients—which also boost lather, color, and smell, and coat your hair with silicone—aren’t innocuous: “Of the 22 ingredients” in a bottle of Pantene Pro-V, “all except three have proved to contribute, or are suspected of contributing, to health or environmental problems,” Bunn writes. And these chemicals enter our water systems, which “can’t remove the diversity of chemicals that Americans flush every day.” So what does Bunn use to clean his hair? Sunlight Dish Detergent.