Patagonia Wicking T-shirt odor free t-shirt check with lady from Goring Health Walks, used for runners Adding a bit of vinegar to your laundry cycle. The acid in the vinegar will effectively break down many odors and act as a disinfectant. It's the bacteria STILL left in your shirt that when your body temp rises the bacteria starts to release the odor. (Happened to my straps on my Dakine pan too after wearing a tank top with it). I use baking soda in the load and oxy clean helps, but I still have one jersey that won't stop. Going to try the vinegar before I give up...love that shirt. Google is your friend - have known this, but here is a better explanation than I'm willing to type... As it turns out, the very attributes that make technical synthetic fabrics such winner at wicking away moisture from the body is what can makes them such a prime destination for bacteria and odor too. Synthetic fabric is constructed with tiny microscopic notches that collects sweat and moves it from the inner layer of the garment (next to the skin) to the outer surface, where it can evaporate more easily. The problem is that these microscopic nooks and crannies are also a perfect place for bacteria to collect. So it’s true that synthetic fabrics are great for running because they wick away your sweat but, unfortunately, bacteria (which causes the smell) easily gets trapped in the fibers and can be very hard to get out. Even after washing! Unless the synthetic fabric is treated with some type of odor block technology you will find that your shirt can quickly start to stink. Also, keep in mind that many brands claim that their garments have “odor block technology” since their garment has “wicking properties.” However, “wicking” should not be confused with technologies that actually prevent odors by eliminating bacteria on contact. Using baking soda helps. Pre-soak your clothes in a solution of water and Arm and Hammer Super Washing Soda (or just use water and a cup of baking soda). You can use the pre-soak setting on the washing machine or do it in a separate container. Then wash and use Arm and Hammer laundry detergent. Try using a special detergent formulated for technical wear, such as WIN High Performance Sport Detergent. Those types of detergents will remove the odor, but won't degrade sweat-wicking or water-repellent properties. Plain white vinegar is an inexpensive and cheap odor remover. Soak your running clothes in a cup or two of vinegar mixed with plain water. Then wash as usual. Or, pour 1/4 to 1/2 cup of white vinegar into the wash (along with your regular detergent). There are also lots of new odor-fighting running clothes on the market. They may sound too good to be true, but these running clothes do actually help keep you dry and odor-free. Although some of them are more expensive than your average running shirts, they're worth the investment because they'll last longer and keep you smelling fresh.