No, the additives aren't known to degrade over a reasonable time in storage. Some years ago, a few oil companies had stated a five year shelf life was a reasonable expectation. Many people were concerned about "additive drop-out" of stored oil, which has been known to happen. A simple solution is to turn the unopened container up-side-down and shake for a few minutes before pouring into the engine. I always up-turn and shake the container before use, even on recently purchased oil. YMMV.