Novolog vs Humalog

Good morning!

Due to an insurance change, I recently had to change from Novolog to Humalog as my fast acting insulin. In theory, I know that they are virtually the same. However, I haven’t found that to be the case. With the Humalog, it takes longer to become effective (I am now taking my bolus 30-45 minutes prior to eating) and it has required an adjustment in my basal level. I am constantly running high (250+), requiring more correction boluses and using more insulin that previously. Is this normal? I know that people here aren’t doctors and I am not looking for medical advice just experiences from other users. I am a MDI and not a pump user.

Just looking for insights. I have a meeting with a new Endocrinologist in a few weeks and am going to add this to my list of tings to discuss.

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Hi Mary-Frances @MFBarry! I am a MDI diabetic, too! I am on Humalog. Although I don’t have the issues that you are experiencing, I would say that every person’s body chemistry is unique. What works for one person may not work for another. I would ask your new endocrinologist to write you a letter for your insurance company. They may approve the Novalog with his input. Definitely bring your hard data to show the change in blood sugar numbers. I hope this helps!

Mary-Frances @MFBarry, I hear your frustration. Humalog and Novolog, although both classified "Rapid-Acting formulations, GENERALLY provide people with very similar results. Although both being rapid-acting, they are entirely different in formulation - one being made from a virus and the other from [brewer’s] yeast; it is possible one will be better for you.

I have used both in infusion pumps and about four years ago the insurance company formulary changed “forcing” me to use Humalog. It turns out with Humalog my body requires less insulin than any time during the previous 65 years.

The basic theory behind MDI is that a mealtime bolus will be sufficient to return BG level to the point where it was before beginning the meal - no more and no less. You MAY need to look at your background / basal dose. It is possible, especially for events affected by your body clock that [such as when you get up in the morning] that you need a bolus supplement to offset the adrenalin-caused glucagon dump from your liver. We are all different, but about the only time I take my bolus before eating is when my BG is already running higher than normal - I rarely take my supper bolus before my first few “tastes”, especially at restaurants.

I second @homeschoolingmomof5 regarding restoring coverage for Novolog: insurances may cover it with sufficient documentation from your physician. My doctor’s office has done that on a couple of occasions and the formulary I needed was approved. Your doctor’s office probably knows what to do.

I’ve switched back and forth several times and haven’t noticed any difference with MDI. But what’s normal for me may not be normal for you. Doctors, even insurance companies, understand that principle very well so you shouldn’t have a problem switching back.

Same here. I suspect insurance companies choose as their preference the insulin for which they’ve negotiated the best price, neglecting the fact that it’s not “one size fits all.” At one point they changed their preference to a type that was not improved for pumps! Thankfully it was not difficult for my doctor to get them to approve the one I needed.

Thanks Dennis (@Dennis ), I didn’t realize the two insulin’s were made differently. Over the last few weeks, I have been tweaking my C:I and my basal which is starting to make a difference. I think I was more surprised than anything about how differently I reacted to the 2 insulins. I am more bummed that my TIR will worse when I meet with the new Endocrinologist. I’ve worked very hard in the year since diagnosis to get into a routine yet my numbers won’t reflect for the visit. Oh well, the life of T1D

I appreciate everyone’s input!

Take care,


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In a way Mary-Frances @MFBarry, it may be to your benefit that your numbers are a bit out-of-line when first meeting with a new doctor. If numbers happened to be “perfect” the doctor might think that you don’t need much assistance and guidance; this way, you have the opportunity to engage in a deeper discussion about your management technique. Take this as a learning adventure. I don’t look at numbers including TIR as a goal, but rather as guides and, when needed, as decision points - I use this data to make adjustments in either foods, exercise, or insulin.

Life with diabetes does have many twists and turns, and often as a challenge. When I was diagnosed, I was advised to establish a routine; time for getting up, eating meals, etc., when I got out of college and into the working world at age 18, I found that nothing in life was routine for me and that “diabetes routine” didn’t fit my very active lifestyle, so I modified what I had been told to “live life to its fullest and MAKE DIABETES fit”. It took a long while with few tools, but somehow now in old-age my TIR hangs around 90% and HbA1c below 6%. Doctors now tell me that I’m unorthodox, but to keep doing what works for me.

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You’re working very hard to control what you can: this is out of your hands. Once you’re back in your preferred formulary you’ll get back on track. Depending on how long you’ve been taking Humalog the effect on your A1C may not be as profound as you’re expecting; but if it is, consider it an unavoidable aberration and show him/her your stuff at your second visit.
I hope things work out well with your new doctor!

I too was a victim of a forced insurance switch. I too found that Humalog doesn’t work as well or as fast for me. My total usage is up by about 18%. I wish you the best in your chosen path. I tried the medical necessity fight which after 2 appeals i lost anyway. I was forced into a medtronic pump by the insurance company and then told the bayer test strips required to calibrate the medtronic sensors were non formulary. I did ultimately win that battle, but i sure wish that our insurance companies would not continuously add to the stress of life. It really is a shame that money and not our Dr’s have the ultimate say in our care.

I had a similar problem with the insulin reversed. It took 3x the Novolog compared to Humalog. My doctor and I discussed it immediately. He prepared a letter to my insurance company and told them they were putting my health at great risk & that he must prescribe 3x the insulin. The insurance company responded IMMEDIATELY and agreed to cover the Humalog.

Your doctor is responsible for this. Make sure he or she is on your side and act at once.

Hi Mary,

I’m so sorry you have to switch short acting insulins. I was literally in your shoes a few years back when my insurance company pulled the rug out from under me and suddenly stopped covering Humalog. It literally took me almost half a year to adjust to Novolog and it sucked. Everything I ate, I had to adjust since apparently only adjusting my sliding scale wasn’t going to cut it. Suuuper frustrating. Anyway, about a year or so after having to switch to Novolog, my insurance suddenly started covering Humalog. I’m assuming a ton of people had complained. Regardless, I’m still on Novolog now since I don’t want to have to go through all of that again to switch back. I had been on Humalog I think for at least ten years if not more before having to switch to Novolog. It all kind of blends ar this point, being a type 1 for 35+ years. Anyway, I just wanted to reach out to let you know you’re not crazy and others (aka myself) have had the exact same experience needing to switch between short acting insulins. I am also on syringes since my skin doesn’t tolerate adhesives. That’s a whole ‘nother story.



I had to change for the same reason years ago and saw no difference. I am guessing your body needs have just changed. Increase Bolus if you are going high after meals only. If you are high before you eat, you need more basal. Could be the stress of change also. Stress is HUGE.

I’ve been on MDI for many years and have had the same problem you describe again and again with the PBMs, who restrict the prescriptions a patient can get in order to boost their own profits. I came across this article awhile back, which perfectly describes the infuriating situation T1Ds face in the USA:

You can apply to get discounted insulin through the manufacturer. I use Humalog and Tresiba, Humalog is not on my insurer’s PBM formulary and so not covered, so I get it for a discounted price through the manufacturer Lilly. Since your insurer/PBM isn’t covering Novalog you are in effect uninsured for the insulin you need and should be able to get a discount, see: my99insulin | NovoCare®

More info on the prior reply: New Insulin Affordability Programs Include $99 Insulin in the US from Novo Nordisk (