Filling your own pens

I’ve been filling my own pens for a while.


  • Not all the disposable pens are refillable
  • Re-filling from a vial is cheaper than buying disposable pens.
  • You can fill them with any amount you want. Rather than having 300 ml sitting outside for months (that’s how long it would take me to get through some of the basal ones), or always having to go into the refrigerator to get one out, I can just fill it with a week’s supply at a time. Only one week’s worth stays outside, the rest of it stays in the fridge.
  • Not all pens give you the half-unit dosing. So I made all of mine with these 1/2 unit pens.
  • Sometimes the disposable ones you get are defective and you have to toss them, wasting insulin.
  • Various insulins come in different pens. They come in various lengths and sizes, and it is not as easy to carry and store several different types from various pharmaceutical companies.
  • Using the same type of pen means that they are interchangeable. If I have a pen that goes bad, I can simply swap a cartridge from one to the other. Using all the same type is like having a bunch of spare pens.

So I use the Lilly Luxura HD pen for everything. I can get them for very cheap at (only about $10 each). They are well made, durable, have 1/2 unit doses, and are easy to refill. Here is how to fill them with whatever you want.

This may look complicated, but it is not. You only have to empty out the cartridge once, and flush it with saline. After that, as long as you are refilling with the same type of insulin, you don’t have to do that anymore. It is just a matter of refilling it, which is very easy.

  1. I start with a sterile surgical drape on the table, because I am not an animal.

  2. Here is the stuff I use to do this. Some syringes, the cartridges for the Luxura pen, vials of insulin, and saline to rinse out the cartridges:

  3. Clear out the original cartridge that you are using. In my case, I am using the Lilly pen and the Lilly Humalog cartridges. You push out the end stopper by using a syringe and injecting with air until it pops out. Then you rinse with sterile saline to remove the insulin that was once in there…

  4. Put the rubber stopper back in. To maintain sterility, it is best to not touch it with your fingers, but use either sterile gloves or an alcohol swab.

  5. Label it so you know what is in there! Then you fill it with insulin from a vial, using a syringe, and also remove the air using a syringe. Not hard. Really is super easy to do.

  6. Make sure you label not only the cartridge, but also the pen.

That’s all there is to it. Now you have refillable pens, filled with whatever insulin you want.


This is a GREAT post, @Eric!

We use mostly Novolog, so we would have to use the Novolog Echo pen to use our spare cartridges, but the instructions would be the same.


awesome post @Eric


Fantastic post! Do you prefer a specific type of saline? Where do you get it?

Also, which pens have half unit dosing options?

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The Lilly Luxura HD (“HD” stands for “half dose”) has 1/2 unit dosing. And so does the NovoLog NovoPen Echo pen.

The saline that I use is the diluent I got from Lilly. It is actually specifically meant for diluting insulin (which I need to create a thread on - it’s what I use to micro-dose with a pen!).

You can get it for free from Lilly if you call them and say you want to dilute their insulin. It does not require a prescription, but they won’t mail it directly to you. They will send it to your pharmacy.

It is PH balanced and so-forth, so it mixes perfectly with insulin, and is sterile. So I use it for both the rinsing and the diluting.

I have plenty, if you want some I can send you a few vials.


Amazing post- thank you.

Have you compared the accuracy of the Lilly pen to the Novolog pen? Just curious.

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I haven’t compared accuracy. I don’t really have any equipment to measure such precise volumes. But I am sure the people at Novo Nordisk and Lilly have had to do a lot of work in that area to get the pens approved. I am sure they are both very precise.

As far as volumes, NovoLog and Humalog units are equal for U100. All my stuff is U100.

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9 posts were merged into an existing topic: Refilling the Lilly KwikPen disposable pen

Since you are opening the pen vial and touching the rubber stopper. In addition to the sterile drape, I would use sterile rubber gloves and try to use as many sterile components as possible in the steps up until the stoppers are replaced back in the pen tubes. Seems like a good place to add critters in your insulin.

On the disposable pens, I don’t remove it.

The only time I remove the rubber stopper is on the non-disposable pen, and then it is only when I am putting in a different insulin then what was originally in there, like putting in Lantus or Levemir in a Humalog cartridge. And for that it is only on the first time. Every other time I just refill without removing it.

Your point is good to mention. When I have removed the rubber stopper, I use either an alcohol pad or use the sterile drape to pick it up and put it back,so I don’t touch it. I should have mentioned that.


I have been refilling my Novolog cartridges quite a number of times and am liking it alot.

There is always a small quantity of the unused insulin in the cartridge that I cannot seem to extract using a syringe, or the pen needle for the Novolog Echo pen. I inject a small quantity of insulin to flush out the cartridge. My concern is that if the remaining insulin were old, I’d want to remove the “stale” insulin as much as possible, and dilute whatever insignificant amount of the stale insulin that’s in there. Is there a technique to removing “the last drop of insulin”?

How many times can you refill the same cartridge? Does the needle insertion area become weakened by repeated use, both by the syringe during refilling and the pen needles?

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Eventually it might wear out. But I use mine over and over. A ridiculous amount.

I think I have some with over a year of use! Have not had a problem yet!

If you empty a Humalog pen, there is about 5 or 6 units or so left. If you fill it all the way up with 300 units, that’s about 1% “old” insulin in there. And it isn’t necessarily bad, just a little bit old.

If you want, you can fill it, empty it by injecting it all out, and then refill it again. You will always have a trace amount of the old stuff in there but it is a really small insignificant amount that shouldn’t cause you any problems. The other option is to take the stopper out, which I show at the beginning of this thread.


I’ve been using a refilled humalog pen with R lately. I emptied the pen, sucked it as dry as possible with a syringe, added 10u of R and emptied it and sucked it dry; twice then filled it… probably overkill but I’m just learning R. BTW R is working really great!


Having never used anything other than a Lantus disposable, my apologies if this is a dumb question.
With the Luxura HD reusable pen, does anyone know if it will it accept other cartridges other than the standard Humalog Penfills?
I have lots of salvageable Lantus cartridges, as well as access to Levimir and Basaglar cartridges, from disposable pen units, if those will fit in the Luxura.
Otherwise, I’m going to have to see if my PCP will mod my prescription from Novolog vials (my insurance doesn’t cover the Kwikpens) for some Humalog penfills to use in the Luxura HD pen, assuming that they will cover those of course.

Following up on Eric’s groundwork, I was able to successfully refill cartridges that were scavenged from the disposable Lantus Solostar empties that I had accumulated.
The cartridges that were scavenged from the Levemir pens would not work, however, as they are just a bit too long to fit into the pen body correctly.
Now I just have to make sure I never need more than 30 units of Lantus per dose!


That’s great! Very cool that you can use a cartridge and a pen from two different pharmaceutical companies - Sanofi and Lilly. I have always been using the Lilly cartridges for everything.

I appreciate the update!

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Nice looking refills!

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Also have some news coming soon for those that asked about doing something similar to this for Novopen Echo refills.

Bottom line, if you have any of the Lantus Solostar or Levemir disposable pens lying around, don’t toss them if you have either a Humapen or a Novopen. There is more than one usable component that can be salvaged from them.

As a Scout leader, I save everything in case I can find a way to re-purpose it for my Scouts, so I had a couple of dozen empty Lantus Solostar pens stashed away from back in the days that my insurance would pay for them instead of just the vials, or the new Basaglar pens instead. So when I decided to order the Humapen HD, based on Eric’s groundwork for doing your own refills, it was with crossed fingers that those salvaged Lantus vials would fit, with the fallback position being to ask my PCP to send in a script for some Humalog cartridges, or ordering them myself from Canada if I had to.


As promised, here is a work up on how to refill your own Novopen cartridge refills, using a vial from a disposable Levemir pen, and the needle cap from a Lantus Solostar pen.

First off, the big difference to note between the Humapen and the Novopen is that on the Humapen, the needle threads are built onto the pen body, but on the Novopen, the needle thread is part of the actual cartridge.


In the next picture, on the left you can see how the threaded cartridges sticks out of the end of the Novopen.
And on the right side of the picture, an important difference between a salvaged vial from a Solostar pen, and the one from the Levemir pen. The vial from the Levemir is a bit longer, and the Solostar vial is a bit larger diameter. As it turns out, the Solostar vial does not fit properly into the Novopen, but the Levemir vial fits just fine.


So now we need a threaded cap for our salvaged Levemir vial. We can try to use the cap that is on the Levemir disposable, but the plastic is very soft, and the cap fits very loosely, and falls off as soon as the vial is turned over.


But…all those Lantus Solostar pens also have a threaded cap, and the plastic on them is much firmer, and, as it turns out, a much better ‘snap fit’ onto those Levemir vials.


With the Solostar threaded end installed, the salvaged Levemir vial now fits quite nicely in the Novopen, and is ready to be cleaned, filled, and put to work. You can see how closely the newly fabricated vial matches the original.

A couple of notes-

Obviously, if you have Novolog empty cartridges, you just refill them the same way Eric has described for refilling Humalog cartridges.

This trick lets you make your own spares, to fill with whatever you need to fill them with.

You have to have a supply of empty Lantus Solostar and Levemir disposable pens to obtain the required parts.

I noticed that there can be a bit of spinning with the new Lantus caps on the vials. I personally plan to use a tiny drop of CA to address that factor.

Why not just use CA to glue the Levemir cap on instead?
I suppose you could. But the plastic thread on those doesn’t seem to be quite as durable as the threads on the Solostar pens. Plus those are a much nicer fit all the way around.

It occurred to me tonight, that, with so many serviceable parts that can be salvaged from the “disposable” Lantus and Levemir pens, I may just place an ad on the local Craigslist offering to buy empties in lots of 5 or more at a buck for each!