"First of all, sweat by itself doesn't smell," Dr. Oz says. "What does smell is when the sweat gets bacteria in it. Some people's sweat have chemicals that are particularly attractive to bacteria. Sweat itself comes out normal in its shape and its smell but the bacteria love it, so they just grow and grow and grow and multiply."
A particularly strong smell signals one of two things: diet and bacteria. This smelly sweat may contain some sugar, but sometimes sweat actually inhibits bacteria growth and sometimes it encourages it. Those with particularly smelly sweat may have bacteria already colonized on their body, Dr. Oz says. "Anti-bacterial soaps are sometimes helpful to get those out. In terms of how much you sweat, that varies a lot, and sweat's not a bad thing because it means you're getting rid of some excess energy. That stated, for a lot of Americans it's related to hormonal problems, so thyroid gland issues are of concern."