Growing up, I was always told to wash my hands with warm or hot water in order to effectively wash off germs and bacteria. Soap and warm water have always been thought of as the perfect combination to help prevent the spread of infections. However, do you really need to use hot water to wash your hands?
Amanda R. Carrico, a research assistant professor at the Vanderbilt Institute for Energy and Environment, told National Geographic, “It’s certainly true that heat kills bacteria, but if you were going to use hot water to kill them it would have to be way too hot for you to tolerate.”
Boiling water, with a temperature of 212 degrees Fahrenheit, is sometimes used to kill germs. When you use hot water for hand washing, it’s usually between 104-131 degrees Fahrenheit, which could kill some pathogens but it could also scald your hands from the sustained contact. Carrico also noted that warmer water can actually irritate skin and affect the protective layer.
Bottom line: washing your hands with warm or hot water is unnecessary. Cold water is perfectly fine!