# Trying not to waste insulin **URL:** \ **Category:** T1D Tech & Daily Management Support\ **Created:** [July 6, 2022, 2:09pm UTC](https://forum.breakthrought1d.org/t/trying-not-to-waste-insulin/72062 "2022-07-06T14:09:09Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![DFBB](https://avatars.discourse-cdn.com/v4/letter/d/58f4c7/32.png) [@DFBB](https://forum.breakthrought1d.org/u/DFBB)\ **Post date:** [July 6, 2022, 2:09pm UTC](https://forum.breakthrought1d.org/t/trying-not-to-waste-insulin/72062/1 "2022-07-06T14:09:09Z")
Hi Everyone, I’m using a tandem t slim pump, (new user), and realize that when I have to fill my cartridge later today I still have some unused insulin in a vial, but it will not be enough to completely fill my cartridge, so I’m wondering if I then empty one vial and go through fill process with a new vial as well? I dont want to waste insulin but unsure of whether you can use 2 different vials during fill process? Phew, sorry for these beginner questions. So many little details that I’m just not sure of and feel confused about what to do. Thank you in advance. ---
**Author:** ![joe](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.breakthrought1d.org/joe/32/2937_2.png) [@joe](https://forum.breakthrought1d.org/u/joe)\ **Post date:** [July 6, 2022, 2:13pm UTC](https://forum.breakthrought1d.org/t/trying-not-to-waste-insulin/72062/2 "2022-07-06T14:13:49Z")
@DFBB It’s fine to use 2 vials. I always do. ---
**Author:** ![wadawabbit](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.breakthrought1d.org/wadawabbit/32/3890_2.png) [@wadawabbit](https://forum.breakthrought1d.org/u/wadawabbit)\ **Post date:** [July 6, 2022, 3:04pm UTC](https://forum.breakthrought1d.org/t/trying-not-to-waste-insulin/72062/3 "2022-07-06T15:04:20Z")
I do it all the time - no problem at all. ---
**Author:** ![Dennis](https://sea1.discourse-cdn.com/flex025/user_avatar/forum.breakthrought1d.org/dennis/32/5527_2.png) [@Dennis](https://forum.breakthrought1d.org/u/Dennis)\ **Post date:** [July 6, 2022, 7:38pm UTC](https://forum.breakthrought1d.org/t/trying-not-to-waste-insulin/72062/4 "2022-07-06T19:38:18Z")
Certainly Dianne @DFBB you can **fill the syringe** from two or more vials. Just DO NOT go through the cartridge fill process twice. Another way I avoid tossing out perfectly good insulin, is that I don’t often change my cartridge and infusion set on the same day. I do change the infusion set, and a do “cannula fill”. almost every three days, but I wait to switch out the cartridge until it is empty - I don’t do the “cannula-fill” unless I’m inserting a new one. The reason I have insulin remaining in the cartridge after three days is because a minimum of 100 units is needed in each new cartridge and I use less than 20 units of insulin per day. ---
**Author:** ![thequetip](https://avatars.discourse-cdn.com/v4/letter/t/f9ae1b/32.png) [@thequetip](https://forum.breakthrought1d.org/u/thequetip)\ **Post date:** [July 9, 2022, 9:53pm UTC](https://forum.breakthrought1d.org/t/trying-not-to-waste-insulin/72062/5 "2022-07-09T21:53:33Z")
Yea, as others have said, should not be a problem. ---
**Author:** ![rpalmer0614](https://avatars.discourse-cdn.com/v4/letter/r/c6cbf5/32.png) [@rpalmer0614](https://forum.breakthrought1d.org/u/rpalmer0614)\ **Post date:** [July 10, 2022, 7:39pm UTC](https://forum.breakthrought1d.org/t/trying-not-to-waste-insulin/72062/6 "2022-07-10T19:39:23Z")
I do not know whether it matters, but I am careful to avoid mixing the insulin from the open vial within the new vial. I prime the cartridge with the older insulin, purge the needle a few times with air, then pull from the new vial the balance of insulin that I need for my 3 day run. That said, I also ensure I extract all of the insulin from the older vial - at least as much as I can… I wish you much good fortune with the T-Slim. I switched from Medtronic to Tandem in December, and T-Slim has been by far a superior system. Cheers.