Backfilling Syringes

This question is for the guys who backfill syringes. How many do you normally backfill at one time? Do you think there’s any concern with the testosterone oil interacting with or eating away at the rubber stopper? Thanks

Normally I don’t preload more than a week’s worth at a time. In the past I have used preloaded pins that sat ready for me for a month with no issues at all. I’ve been told that some oils will leach chemicals from plastic, which is why people caution not to buy cooking oils sold in plastic bottles…but I’m not sure if syringes are made with the same cheap plastics as your run of the mill canola oil.