Smelly Syntherics

Ok so as most everyone else I bring synthetic shirts into the back country and I wear them around the house too. I have noticed with these shirts that if I get even a tiny bit sweaty the shirt will take on a sort of musty smell that wont go away until after a good wash. The smell is not me though cause this does not happen to cotton shirts.
Does anyone know why this is and if I can fix it?

Shrike you can't fix it. Some underwear has "silver" in it to prevent this, but not any quality stuff that I know of. As long as it isn't polypropylene which melts in a drier, the heat of drying it "burns out" the smell. All I can say is stop wearing it around the house - I did. What you get from this stuff is DRYNESS next to your skin, which to me is worth the smell since its generally under my ski gear. If you stink too bad to get into a sleeping bag with your self, consider using underarm deodorant.
Jim YMMV

The old-fashioned housewife's remedy: Using baking soda or borax in the wash water really helps get rid of the odors. If it's really bad, wet the garment, rub baking soda into the armpits (gently) and let sit 15-20 minutes before starting the washing machine. Baking soda has many uses out on the trail, too. I use it primarily for washing my teeth (dentist-recommended, far lighter than toothpaste, doesn't leave white spots on the landscape when you spit), but it also can be used as a deodorant, in a paste to soothe insect bites/stings, and a few zillion other uses.

OK, we women don't get as ripe in the pits as you manly men do, but I was married for 20 years and raised 3 boys, so I do know whereof I speak!

I've been told that merino wool doesn't get stinky like synthetics, but this came along long after both ex-hubby and the boys left home--you guys will have to test this one out!

I have a few pairs of merino wool socks and they not only do not get as stinky as easily as synthetics, they dont stink at all, ever. I wore a pair in full hiking boots and they did not stink at all at the end of a five day trip.
My mom still made me wash them but no one would have noticed if I had just gone on wearing them:) LOL

I've had that experience with the synthetic shirts I use for running. That's why I wear merino when hiking instead. I've experimented with wearing the same merino shirt for several hiking days when I have been hot and sweaty. No smell at all. The synthetics seem to magnify bad smells I don't understand why this is. My strategy is take them off and wash them right after running. Can't imagine backpacking with them. I wouldn't be able to sleep in that smell!