A new hair hack is doing the rounds on TikTok these days: upside-down hair washing. The trend simply consists of applying, then rinsing, your shampoo and conditioner with your hair over your face.

Washing your hair can sometimes seem like nothing more than a time-sucking chore. "Shampooing removes sebum or oil that normally coats the hair shaft," Dr. Brendan Camp, a dermatologist at New York’s ...

If you’re someone whose hair gets greasy a bit quicker than most, you’re not alone in contemplating whether it’s time to hop in the shower, even if it’s only been a day since your last wash. But ...