Odor analysts have determined that polyester gets much smellier than cotton or wool. But sweat is not to blame, because sweat itself does not stink. It is the bacteria that live in your armpit and groin that produce the funk.
Up to 300 types of bacteria inhabit your armpit. Some are associated with normal body odor, while others produce more unpleasant smells. Interestingly, the bacteria that has a “normal” smell is more prominent in a female armpit, while men tend to have more of the stinky version.
But why does this affect your clothes? Natural fibers like cotton absorb moisture (and stink) where they are trapped and cannot reach our noses. Not the case with the moisture wicking synthetic fabrics, which do not absorb moisture. Instead they attract oils from your sweat, which sits on your clothing like a buffet, waiting for stinky bacteria to eat it up.