I'm not sure exactly what you're asking. Unopened, the cartridges/pens are good until the expiration date stamped on the box. Once opened, there's a bit of debate. The manufacturer says that Lantus is good for 28 days. On the Tilly Protocol, they indicate that members of the German forum have used Lantus (not sure if it's a vial or cartridge) for 6 mos. I don't know if there's anyone here who has had Lantus last that long. Some people are able to get longer than 28 days. Probably the longest is 2 months but there are instances where numbers just get weird. Others can't get longer than 28 days.