Does polyester viscose material stretch

i hope not i jus bought a shirt made out of 100% viscose :-s

I wouldn't recommend washing it in normal wash. I have a 100% viscose shawl, and it is recommended either hand wash (don't be too hard on it though) and then warm iron it on the wrong side while still damp to reduce the crinkles.

Also, you can get it dry cleaned to be on the safe side.