I am on estradiol valerate
My Dr, the nurse, and 2 pharmacists told me to toss mine after 28-30 days because it starts breaking down after a few weeks and isn't worth injecting anymore. Nobody mentioned contamination. The pharmacists were making exrea sure I knew I needed to wipe the top of the bottle with alcohol prep wipes to avoid contamination.
I'm getting refills every 4th injection anyway, but there's so much left inside, I kind of wish I could independently verify it is breaking down (not just find info online, actually have it tested somewhere or something idk) because I know someone who would absolutely want the extra...