Surprisingly, sweat doesn’t actually smell. In fact, it’s completely odourless. We call the smell associated with sweat “body odour” (or BO) and it’s caused by the bacteria that lives on your skin. Your body is home to millions of harmless bacteria that thrive in moist, humid and nutrient-rich environments like your underarms, producing by-products that have a very distinctive smell. Smelly ‘sweat’ isn’t harmful to your health, but it can be a bit embarrassing. To help prevent sweaty body odour, ensure your underarms are clean and dry and use an antiperspirant regularly to keep you feeling (and smelling) fresh.