Ahhh yes, the million dollar question. In the land of type 1 diabetes and rapid acting insulin, everyone wants to know, which works better…Novolog vs Humalog?


Thank You Insurance Companies (not!)

You’re probably here because your insurance company has pulled the plug on your beloved insulin and is making you switch to the dark side. Whether they signed a deal with Lilly (Humalog) or Novo Nordisk (Novolog) you’re left in sheer panic because WTH insurance companies?! This is my life juice you’re messing with here.

You’ve been reassured by your doctor…and their nurses…and the pharmacist that there is no difference between the two brands…

It’s like pepsi vs coke

– my doctors nurse.

Well, if you know anything about pepsi or coke then you know… while it’s true that some can’t taste the difference, others most definitely can. Same is true with Novolog vs Humalog.


Show me the differences! Novolog vs Humalog

But first, the similarities.

Both Novolog and Humalog are human insulin analogs. This means that they are a synthetically altered form of human insulin – the kind that you find naturally occurring in the human body (as opposed to being extracted from cows and pigs – like it was back in the 20’s).

Both should begin working in about 15 minutes after injection, should peak in about 1 hour, and should continue to work for 2-4 hours.

What’s with all the shoulds? Everyone reacts to medications differently; insulin is no exception.

…which brings me to the differences

In Humalog (insulin lispro) the amino acids for proline and lysine have been swapped. This means that the amino acid, proline, has been substituted for lysine in position 28 of the B-Chain, and lysine has be substituted for proline in position 29 of the B-Chain.

Insulin Amino Acids for Humalog


In Novolog (insulin aspart) there is only one substitution. In position 28 of the B-Chain, proline has been completely removed and replaced with the amino acid – aspartic acid.

Insulin Amino Acids for Novolog

This small swap of amino acids can mean the difference of your body responding extremely well to the insulin or not so much.


How Your Body Will Respond?

Unfortunately, you won’t know until you try it.

For me personally, I have been on Novolog from the start. But when my insurance company signed a deal with Lilly I was forced to make the switch to Humalog. I tried to get my doc to write a prior auth so I could stay on Novolog, but her hands were tied because she needed to give the insurance company a legit reason for why I couldn’t make the switch. And since I wasn’t pregnant (which would have been a legit reason not to switch) and I had never tried Humalog, there was no way I could get a prior authorization – I had to at least try it.

…and as you may have guessed, it didn’t work for me.

It was as if my body hit a major wall of resistance with Humalog. It took well over 15 min to start working (probably closer to 30-45min) and it didn’t seem to ever peak. My boluses and basals weren’t working, even when I doubled my dose; I struggled to stay under 250mg/dL with Humalog.

But don’t think Humalog is the bad guy. For as many stories I’ve heard about Humalog not working, I’ve heard the same amount for Novolog not working. And for many, both work seamlessly! So you really won’t know until you’ve tried it.


So Why The Switch?

Why do insurance companies like to switch drug coverage?


Humalog is less expensive than Novolog. So most insurance companies will choose to cover Humalog vs Novolog when trying to cut costs. However, sometimes insurance companies will sign a contract with a brand if they can get a good deal, which is why you might also see them cover Novolog vs Humalog.

But in the end, no matter what deal the insurance companies signed or what insulin they choose to cover, your doctor can write you a prior authorization to get you back on the insulin that works for you.



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Novolog vs Humalog Pinterest




  1. Sara January 12, 2018 at 9:32 am - Reply

    Great article! I know that I can personally make the switch seamlessly, but my daughter (also T1) is incredibly resistant to humalog. We couldn’t get her below 300 when we switched her. It was like we were injecting her with water.

    • T1D Living January 18, 2018 at 9:12 am - Reply

      Wow so crazy! That was my same reaction on Humalog. Interesting how it effects everyone so differently!

  2. Alex February 11, 2018 at 7:49 am - Reply

    Thank you for a great article!
    I respond well to both insulin. But gets a more rapid response by Humalog. It also goes out of the body faster. Which is preferable when use a pump.
    However, I recover much faster after training with NovoLog.
    What is the reason for my choice of these insulations (NovoLog).
    But now switch to the new Novo Nordisk Fiasp (NovoLog + vitamin B3)

    • T1D Living February 20, 2018 at 11:31 am - Reply

      interesting! It’s so amazing how differently everyone responds. I haven’t heard of the Novo Fiasp, I’ll have to check that out.

  3. Brandon Smith July 15, 2018 at 11:09 pm - Reply

    It’s the same for me, but my insurance has denied the prior authorization for the Novolog. I don’t know what else to do.

    • Brandon Smith December 7, 2018 at 11:02 pm - Reply

      They have denied everything my doctor has tried; pre-authorization and exception. My insurance just responds with a generic letter stating that with the board at UAMS, there is no difference between Novolog (or Fiasp) and Humalog. Even with a lawyer looking at my insurance policy, it says that they will not cover something not listed on the preferred drug list.
      I have been receiving samples and paying out-of-pocket for Fiasp, but I cannot afford to keep doing so.
      Any ideas or recommendations?

  4. Julius Lloyd September 6, 2018 at 9:59 am - Reply

    How in why is it ok for companies to play Doctors with someone they been Giving a good Medicine to change their Medicines with out notice or explain the pros of cons.is that legal.?

    • Anonymous September 6, 2018 at 10:04 am - Reply

      Can this be taking to court.?

    • Tammy August 9, 2019 at 7:06 pm - Reply

      I have the same with my insurance also. My insurance for years would cover Humalog and I use Humalog. Now, insurance will only cover Novolog. I tried Novolog for 3 months and kept records of how much I took and even had A1C done to prove it wasn’t working. My doctor sent this all in and my insurance still refused to coverage the Humalog. I was told there is NO DIFFERENCE and that I did not nor my doctor know what we were talking about. I have been on an insulin pump for over 15 years so my dosages were the same but I ended up having to do shots also with my pump just to get my sugars down. With Humalog you can call Lilly and they will help you with the cost some but you have to call them. It is also limited to how much they are able to help you. I do not know if Novolog has the same thing or not. I would if you go to the Novolog site online and see if they can help you with a card or something to help pay for the insulin.

  5. Kathleen Clark November 26, 2018 at 11:51 pm - Reply

    I’ve just found out that both Lantus and Humalog are being dropped for 2019 and only Levimere and Novalog will be available. Period. Last time I tried to use Novalog, it was like using water, no matter how much I used. It took a trip to the ER to bring it down, and throwing out hundreds of dollars of insulin. My body is really sensitive to Rxs , and also has idiocentric reactions , so I HAVE to be really careful! Do I have ANY chance at over-riding this?

    • T1D Living November 28, 2018 at 2:25 pm - Reply

      I feel your pain! Yes, there is a way of overriding this! Have your doctor write a “prior-authorization” for Lantus and Humalog. The insurance companies have to honor it. It may cost more than the “in-network” medicine, but insurance MUST cover it if your doctor sends them a prior auth form.

  6. Amy Burt April 23, 2019 at 4:23 pm - Reply

    I have been diabetic for 33 years and insurance changed me to Novolog from Humalog. Well it didn’t work. Everyone tells everyone Novolog and Humalog are the same when they are different. The insulin went cloudy slightly and l skyrocketed and stayed to 500. I tried then taking Apidra but it still didn’t work. They did change me back to Humalog after l switched insulin’s with someone then got a lab test. About every new doctor wants to try and change me and I have to fight with them to keep me on Humalog. I am it seems, super sensitive to different things but thank God insurance listens and kept me with what works. After 33 years you would think the doctors would listen when I tell them to keep thing’s the same.

  7. Avinash January 14, 2020 at 8:58 am - Reply

    Thank you for sharing your story. I am in the same boat as you, but opposite (Humalog to Novolog). Everything you tried, I tried. There’s no logic to the bolus plan, carb count, or correction factor! Its as if I may as well be on NPH and restrict my diet to 3 standard meal items!

    I’ve been a pharmacist for 10 years now (T1D x 15 years). I mention my profession because I have to deal with these “back door” deals between PBMs, Insurance Companies, and Pharma on daily basis at the customer level. While there are fall back options (manufacturer rebate coupons, GoodRx on a generic equivalent of Humalog, or formulary adjustment review) most times for well controlled diabetics, we have no recourse. Even worse, we toe the line of the medical insurance plan dinging our monthly rates because there was a hypo-/hyper-glycemic emergency requiring medical attention. You could explain this situation could have been avoided if my formulary didn’t require the switch in the first place (but that will fall on deaf ears despite a case # / ticket escalation, etc. etc. etc….). Itliterally seems the insurance companies stack the odds against you for success when it comes to your health sometimes. And that’s criminal..

    Sorry for the tangent, wish you all the best in your glycemic control. Keep fighting and leverage the health technology resources to your advantage with more strict monitoring.


    I’ve fought PBMs for a long time, and sadly, they will dominate the RX profession.

    • T1D Living January 15, 2020 at 3:33 pm - Reply

      Health Insurance companies are cesspools. Their actions are completely disgusting and they fail to help the very people they claim to serve.

  8. Zuhra March 16, 2021 at 9:45 pm - Reply

    interesting first person account of using these confusing drugs… Zuhra,RN-BSN

  9. Anonymous October 26, 2021 at 10:43 am - Reply

    Thanks for this interesting article and feedback comments.
    I have just been switched from Hum to Novo. We’ll see how it goes!

  10. Ben December 7, 2021 at 6:58 am - Reply

    Great info. Been a T1 for about 30 years, more than half of which I treated myself with no doctor intervention at all. 6.9 A1C through that time using syringes and 70/30. Been on pump w Humalog last 10 years and must use an M.D. for prescription. A1C hasn’t changed. Thankful I’m able to semi-succefully treat myself as I’ve read a few stories of others having many various issues. I appreciate the technical info regarding the manufacturing of insulin. Very interesting.

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