Does "expired" test prop still work as well as "non" expired test prop?

My doc put me on test prop. I went to day to the compound pharmacy to fill my script. The pharmacist told me that "by law" she has to tell me that the product will expire in 3 days. I asked her if it really does expire in 3 days or she is just supposed to tell me that. I couldn't pick up too well on what she was trying to tell me. All she kept saying was..."it's the same product you used to get and its made the same way".