Users debate whether pens risk contaminating an entire vial if a blood vessel is hit during injection. One person reported blood entering the vial and discarding it, while others say any backflow stays in the needle and is extremely rare. Many prefer syringes for simplicity and known dosing, but pen users highlight painless shrouded needles, easier travel, precise odd doses, and less waste when filtering into cartridges. Testing pens with insulin syringes is suggested to verify output.
What this discussion establishesWhether pens are worth the cost and setup versus the reliability and lower perceived risk of traditional syringes.
Still openHow common vial contamination actually is with pens and whether it ruins the remaining medication in practice.
Nothing here is advice.
I got my injector cartridges recently, yet something my significant other said has left me uneasy. What if I puncture a tiny vein while administering the dose—could blood flow backward into the container? That might spoil the entire batch, forcing me to discard it all. Does this occur often with these devices, or has anyone encountered it? Maybe the old needle-and-bottle approach would prevent such problems altogether.
Any backflow would stay in the needle and never reach the vial, so there is nothing to worry about on that point. I do want to mention issues with some non-brand pens that do not deliver the right amount. One I tried put out only 3.5 to 4 units when set for 10. Choose a good quality pen, check it with an insulin syringe, and go ahead and use it.
Thanks for the info, this is all pretty new and a bit nerve-wracking for me. How exactly do you test it with a syringe? Do you just insert it where the pen needle attaches and push the button like normal?
Yeah, that exact issue occurred with me once. The needle must have punctured a vein because some blood entered the container, making the contents unusable, so I discarded it. I've returned to using needles instead. It's possible I made an error myself and I don't want to put all the fault on the injector, yet personally I'm continuing with needles for now.
Im really of two minds now...
Pretty much. First coat the insulin syringe with BAC water to cut down on sticking. The video that showed me the method demonstrates the technique. On the blood backflow concern, the report above is the only one I have heard of it happening. It must be very uncommon.
Sorry, I'm old school. With a syringe you cannot even feel the 31g needles. It only takes a short time to draw up by the time you clean the vials.
I have stuck with syringes. The pens seem pricey and involve extra steps to load even if they save a little time per injection. Each week the total time spent reconstituting and injecting probably ends up the same either way. Do any regular pen users see it differently? Are we missing something?
Syringe for me. It is straightforward and I know exactly what dose I am getting. I have come across problems with pens and their dosing amounts.
If you filter, filling a pen is as straightforward as filling a sterile vial. It was hard to reach my right shoulder with my left hand for one peptide. You only need to clear the air once per cartridge. A decent pen gives more consistent dosing than a syringe, though that may not matter if moving to smaller volumes or non-round numbers. There is less waste because you do not lose a drop on each purge and you can empty the cartridge completely, whereas some always stays in the vial. These are just my reasons for using a pen for some things and staying with the usual method for others.
I agree it has to be a rare occurrence. Looking back I was injecting in a poor spot on my thigh so that was my mistake. I have watched videos since then and now do it properly. Still, it did happen so I guess it is possible.
I started with standard insulin syringes then switched to pens and have no reason to go back. The pens cover the needle and are completely painless. Some people react more to seeing the needle enter their skin. With multiple peptides and travel, pens are simpler because one pen works for several by swapping vials. The small pen needle also creates less medical waste for travel. Reaching the back of the arm or awkward spots is easier. With a quality pen the dosing is accurate, especially for uneven amounts like 16, 28 or 32 units. When filtering peptides there are no extra steps beyond adding a vent needle to load a 3 ml pen cartridge versus a round vial. Some people with poor eyesight struggle to read syringe markings while pens have larger
Old studies on insulin pens found human cells or hemoglobin in used pens. That led to the rule that pens are for one person only and changing needles is not enough. This concerns disease transmission though and does not necessarily spoil the contents.
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