Shelf Life for Test Cyp?

Was wondering if anyone knows the shelf life of Testosterone Cyp. The bottles are unopened from a Dr. office, but they are expired. I was wondering if they are still safe to use and how long before they would be inactive or loose their sterility??? Any help would be appreciated…Thanks

Degradation is slow; something like 5% per year. BBB is the expert here.

Thanks, I appreciate the info. I just wanna make sure they are still safe to use.