Doctor advised me I can use Novolin R instead of Novolog

At my usual 3-4 month check up with my diabetes Doc.,(Endocrinologist)
I asked if I could use Novolin R and stop the expensive Novolog Kwikpen.
She quickly responded, “They are the same”. Just different timing.
Take Novolin R 30 min before eating and it has a peak of 1/2 to 1 hour later than novolog, and it lasts maybe an hour longer.

I was amazed. Don’t need a prescription. Went to Walmart, asked for a 10ml bottle of Novolin R from the clerk in pharmacy $25 USD.
Then I looked up on youtube, how to refill a novolog Kwikpen. Humalog pens just need to be unwound and they can be filled with Novolin R using the small insulin syringes 50 units at a time.
Must be careful of the 28 day rule of expiration. Once the Vial is open or the pen is refilled, the 28 day expiration on almost all insulins.

This was so amazing. I have used Kwikpens for 4 years. I am on Medicare, but after my first order, I enter the Medicare Donut hole. Costs almost triple.
Now, I travel with and eat out with a Novolog pen and when I eat at home,
I just use the Novolin R 30 min before the meal.
Every body reacts differently, but my body reacts exactly the same to this Novolin R from Walmart. I am not a Doctor, so all of this is just my personal experience. Always check with you Doctor for their direction and counsel.


I see in your profile, you are Type 2. Do you think you are totally insulin dependent, or does your pancreas still supply some? Do you also use a long acting insulin like Lantus or Levemir or oral meds?

Your suggestion may be better for others in same situation.


Glad your endo is open to suggestions. One thought, when switching medications you may want to rinse your Kwikpen with sterile dilutent so you aren’t mixing medications in the pen.

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I’m in a similar situation.
In fact, at my last endo appointment, it was suggested that R would be a much better treatment option than the faster acting insulins.
One caveat to consider, for most, the duration of R is substantially longer than the rapid insulins. This is actually the reason my endo wants me to switch.
If you are doing your own dosing calculations, this may make calculations for insulin on board a bit more tricky.
If you are using a dosing scale, it also means that, depending upon the timing between meals, you may still have substantial amounts of insulin still in your system.
Making sure you test your glucose if anything feels ‘off’ is imperative, especially when switching from one variety of insulin to another variety with substantial performance variations.

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I’m very curious how important (in the real world) the guidance to discard a vial after 28 days since first opened is with R?

I keep it in the fridge… do you guys consider it a good rule? Total nonsense? Somewhere in between…

Just today I took a bunch of novolog with a fatty dinner and my bg plummeted, then later skyrocketed… would have been perfect with R instead.

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Novolin R has a different profile from Novolog/Humalog. It definitely has its uses but it isn’t suitable for high-carb meals, especially if the protein/fat content is low, and just taking it 30 min before eating would not work for most type 1s, depending on the meal. It can take up to an hour to kick in and peaks at 2-3 hours, which is useless for most carby foods that can peak within 30 min to an hour. It also can last 6-8 hours which is much longer than Huma/Novolog. This is why so many type 1s struggled with it when it was the only fast-acting insulin. It is fantastic for knocking down protein/fat spikes that happen hours after eating however and may be useful for some very low-GI and/or high-fat/protein foods. It is also useful when just eating protein without carbs or with a very small amount of carbs, as its profile matches the timing of gluconeogenesis conversion of protein into glucose almost perfectly.

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I haven’t used it lately, but in the old days of using that stuff I never paid attention to the date.

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I’m still meaning to start a thread on it, but breakfast is the best example I can give for how useful it is. My usual pre-work breakfast is now eggs, cheese, peanut butter and maybe some hummus. I use Novolog for corrections or to stop DP only when I wake up. Usually I’ll take just 0.5 u of Novolog to stop the DP, and more if I wake up high or none if I wake up low or in the low 4s since DP will kick in and raise me. I’ll take ~3 u of R for breakfast and it matches the digestion profile almost perfectly. It probably helps with DP as well, if I was eating the same meal for lunch or dinner I would likely take 2.5 u. I can almost predict what my BG will be a few hours after breakfast eating this way and dosing with R. If I were to take Novolog and eat toast (my old fav lazy breakfast), one day I would be perfect an hour later, the next day I would be 11 and the next day 3. Also should mention I don’t pre-bolus when using R, as the delay is exactly what I want to match when protein starts converting.

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So even if a vial was open day 6-8 months in the fridge you figure it just doesn’t matter?


The vials already have air in them, the insulin is not in a vacuum.

The cap on a vial does nothing, because there is a rubber stopper that actually seals it, not the plastic cap. The only thing the plastic cap does is let someone know the vial has already been started.

You take a sterile syringe and inject air and then remove insulin. True, you are not injecting sterile air. But you are not running around and purposefully collecting samples of various bacteria in the syringe and injecting it. So the inside of the vial is still relatively sterile. and the rubber stopper filters most bacteria from entering the vial.

So my point is - what difference is there between an unopened vial, and one you have taken some insulin out of several month ago? Not much!

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I suppose the difference is that you’ve introduced atmosphere to the vial. And I have no idea what kind of “air” is in there before they’re used… or if matters one iota in terms of not degrading the insulin over time…

I think you have to make your mind up about when you are going to throw it away, but I tend to agree with Eric’s sentiment that unless you doing things that introduces foreign stuff into the vial you will probably be ok for much longer than the stated dates.


I personally suspect it’s nonsense. But the only way to know is try, right?

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The Novolin R has worked well for me as a type 2.
About the 28 days. I have seen people post that they have used refrigerated insulin, (after it is room temp), and it has worked effectively months after the rubber seal on the vial has been penetrated by a needle.

I used Novolog and Toujeo kwikpens 6 months after their expiration dates that were stored in my fridge. They worked fine and I had no problems. The rule seems to be not to use if the insulin is cloudy or you have bad feelings or reactions after using.

I have been very happy that the Novolin R has worked for me almost the same way that quick acting Novolog worked. ( I just wait 30-45 min before eating my meal.

Thanks for the comments and input.

Charlie Furniss


I hope you do start a thread. I’m very interested…

I’m currently researching and I found that the 28 days has something to do with the potency of the insulin and has not much to do with it being sterile. So if you find that it works a bit differently after about 30 days it’s because the potency is becoming weaker and therefore you should be more careful.

I suspect it is both, but bear in mind that in the US the typical supply is one month, which is 31 days, so that’s three days without insulin, 'til you get your next fix. So these are a set of rules which, if you live by them, you will surely die by them.

The rules for the insulin which I have by my side do, indeed, repeat this. The 28 day rule is for insulin stored “at room temperature”[sic], qualified as “below 30[Centigrade]” (my room temperature is over that regularly for half the year). The storage lifetime “in the fridge” is “until expiration date”, which on my insulin vial is September next year (2020). And thou shalt not freeze thy insulin under penalty of deeth, or something like that.

All this stuff was written to be safe: if you store your insulin at 30C/86F for 27 days and then inject it and it does not work, in the US you can sue them, and not just you; anyone who can’t afford insulin and needs to make an honest dime.

Yet the science doesn’t work that way and they are still being safe in the real world of science; my insulin does survive my room temperature, which certainly exceeds 30C/86F, sometimes even in winter.

What insulin doesn’t like is being left on the back shelf in the car in the parking lot at Walmarts, but no one likes that.

Common sense is all that we have left, given that law and science aren’t willing to make any definitive statements. Insulin will last more than 28 days in use so long as you remember your life depends on in so you should treat it better than yourself, but not that much better.

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