How long can you leave/Keep Steroid inside a syringe?

[Test Monsterone]

You can, but as I found out recently, some of the solvents in oils cause a deterioration of the rubber plunger, and possibly of the plastic barrel itself. Maybe it's nothing to be concerned with, but I'd rather keep the oil in glass until I need to inject.

[Wannabhuge14]

I never keep mine loaded any longer than over night.

[Gallowmere]

You can, but as I found out recently, some of the solvents in oils cause a deterioration of the rubber plunger, and possibly of the plastic barrel itself. Maybe it's nothing to be concerned with, but I'd rather keep the oil in glass until I need to inject.

Pretty much this. You’re not saving any time nor effort by preloading a bunch of shit, so why bother anyway? The hydraulic physics don’t change just because you’re drawing a bunch at one time.
If there is even a 1% increased chance of the stopper being degraded and you ending up with a sterile abscess from foreign body injection, is it really worth some misplaced sense of convenience?