Living with #Lyumjev. Almost a year in review…

Lyumjev. Still the newest insulin available and still the fastest kid on the block. But a year with it hasn’t always been the most straightforward of considerations…

11 months ago I embarked on the Lyumjev Adventure, having sought a private GP to write me a prescription so that I could purchase Lyumjev from a pharmacy, as the NHS in my area had not added it to the formulary. Roll forward 11 months, and little has changed. While Lyumjev is more available for a number of people in the UK, there have, in the 12 months from June 20 to May 21, been prescriptions for only 759 items containing Lyumjev in total. To put that in context, its older, out of patent brother, Humalog, had 398,970 items prescribed. Yes, you read that correctly. there 525 times as many items of Humalog prescribed as Lyumjev. And Lyumjev costs exactly the same on the BNF.

And as this chart from data shows, the largest proportion of those were in the Derby and Derbyshire CCG.

So not only is the fastest insulin available hardly prescribed anywhere, even where it is prescribed, there’s only really one CCG that stands out. Across London, where of course there’s supposed to be a London Wide Clinical Commissioning Network, as with the Libre, we have to wait for each region to get it on their formulary. South East London hasn’t got it yet, South West does, and North West will apparently never get it because the commissioners there refuse to prescribe any novel insulins as they will in the future be more expensive than biosimilars, and therefore if you live in that area, well, you’re a in a bit of a bind.

What this all highlights is that access to Novel diabetes treatments (not just pumps, CGMs and closed loops) remains variable by postcode and payment authority, in spite of the costs being the same as Humalog. What was it we said about having a single approval for the UK? Surely, if it is o n the BNF, then local politics, and the waste of time and money this entails, should be removed, and it should just be prescriptible. But leaving the intricacies of the UK system aside….

How was living with Lyumjev over the past 11 months?

Firstly, more expensive than I’d have liked, given the lack of access via the NHS. But I can appreciate that even with that, and paying out of pocket for it, it was hugely cheaper than we see in the USA.

From a an end user perspective, however, it’s been more interesting.


There are multiple posts from the second half of 2020 where I found my feet with the insulin. Those can be found here, here and here. I won’t describe those first months as plain sailing. They weren’t and it was not a lot of fun. Once I finally got to somewhere where I could tolerate it, it became easier, but the goal of fully closed loop has been a challenging one, given my issues with the u100 version of the insulin. In a pump it has taken some getting used to, and anecdotally, other people have had similar issues, and after my initial concerns I had six months where I generally used mostly Lyumjev, and occasionally a mix of Lyumjev and Fiasp. While using the u100, I found that I generally need to change sets after two instead of three days, with only occasionally getting a full life out of the set.

The other major observation was that once glucose levels started to rise significantly outside of a normal range, the effectiveness of Lyumjev seemed to drop off, and the requirement to increase dosing to handle highs was much more evident. This may have been due to its make up, but it’s also possible that the different profile may mean that there is less tail insulin, meaning you need to boost the amount you need to drop glucose levels more and sooner. I remain to be convinced on the latter point, and others have also mentioned this reduction of efficacy in using Lyumjev.


After 6 months of u100 Lyumjev, a suggestion was made in one of the closed loop groups that u200 might work more effectively. So a number of us sequestered some. For those who aren’t familiar with u200 insulin, it is twice the level of concentration of insulin molecules per ml, ie 200 iu per ml instead of 100 iu per ml. What’s also significant is that the Lyumjev has the same amount of Treprostinil per ml as the u100, but because you have double the concentration of insulin, you get half as much additive due to the reduction in volume taken. The immediate reaction to this would be that with less accelerant per dose, you might expect it to work less quickly. And similarly, historically concentrated insulins have moved more of the action to the tail of the curve.

My experience with Lyumjev u200 rather broke that set of assumptions. I found it worked better for me than the u100. The action appeared as good if not slightly better. The insulin obviously lasts longer in the pump reservoir becuase you’re using half as much (ideal for a smaller pump with a smaller reservoir) and as there’s less additive per dose, I found that I have had fewer site issues.

Now, here’s the BUT. U200 Lyumjev comes in Kwikpens only. It has not been approved for pumps. oref1 doesn’t work in u200 concentrations. So this is an entirely off label use, adjusting values to half or double what they would normally be with u200. It’s not something for the fainthearted. I have, however, found it to work better for me than the u100 version. I definitely prefer it.

That’s not to say that at high glucose levels, you don’t need more insulin. That still appears to be the case.

Using Lyumjev in a fully closed loop?

One of the key benefits that many of us believed was that Lyumjev would enable the creation of a fully closed loop version of the DIY APS systems. Admittedly, this is insulin only, but that’s better than nothing. It means you may have to do some tricks to achieve the required variation with exercise, but as this has progressed, we’re starting to see some real performance using a combination of Lyumjev and changes to the original oref1 code that is starting to produce some interesting results.

Back at the end of April, TIR was around 85% with TBR (Time below range) at around 3-4%, using early versions of closed loop code.

While that’s not too bad in real world terms, there are probably too many lows in there. Similarly the longer term measures show a 6.1% HbA1c, a PGS of 27.47 and a GVI of 1.47. Again, in the real world these are really impressive results.

But it doesn’t stop there. Work has progressed on using this faster insulin to generate a “better” closed loop. Three days into testing this development and the results are looking even better. This is why we wanted the faster insulins, and why the u200 really helps.

If we look at TBR and TIR here, we can see that the improved algorithm really does seem to be achieving some amazing things. These three days were all high carb days and included extra large Domino’s Pizza, chocolate, cakes, potatoes, etc. This has been left to run of it’s own accord with no manual intervention. It’s really quite an astonishing feat and demonstrates why faster acting insulins are important.

After nearly a year of Living with Lyumjev, we’re starting to get to where I hoped we might.

Truly outstanding results with minimal intervention.

That’s what a closed loop should offer.

Living with Lyumjev? It took some time to get here, but at last it’s a welcome bedfellow.


  1. My experience with FIASP is quite equivalent to yours, but for me the big step ahead was to increase the sensitivity factor up to 1:600, softening system response and leading to A1C levels of 5.6-5.8. I had to increase the pre-meal bolus, but now I feel great!

      • I started pumping in 2005 with ISF in the range of 32-35, as most of us.
        Since 2018 I used AndroidAPS and I found that way higher ISF lead to much softer movements, despite demanding a better understanding of the ratios for meals.
        I strongly encourage you to test as it helps improving TIR and also A1C…
        Good luck!

  2. My amazingly supportive team have added Lyumjev to the formulary across Sussex. I’m two months in. My experience is that I sometimes get stinging at my site when bolusing, no skin irritation/redness. Still struggling a bit with lows when exercising (but hot weather has added another variable into the mix. TIR in the 90s. If meal

    • I too have been lucky enough to have Lyumjev prescribed by my GP who appears to have ignored the local bureaucratic regulatory constraints. I have been using it now for two months and inject with it 4/8 times a day, but I have only found it to be a marginal improvement on Humalog – 69% in range with Lyumjev compared with 64% Humalog. The suggestion about u200 makes sense and is helpful to me as, despite pre-bolusing the insulin seems to take at least 75 minutes to take effect and sometimes longer. After reading this article however I will definitely be enquiring to see if a change is possible.

      • The latest comments regarding Lyumjev are interesting. Since I last commented in July 2021, my endocrinologist has put me on Fiasp three months ago which, for me, is a vast improvement as it reacts much more quickly although I have found it necessary to increase my basal dosage by about 10% per day.

  3. Thank you for this precious info. We do not have this insulin approved in Slovenia, but some curious PWDs have already been asking me about it. Do you have reasonably high doses of Lyumjev? In that case u200 should indeed work better/faster as insulin is absrbed quicker from a ‘smaller insulin pool’in the subcutaneous tissue. Have not heard that action would depend on the amount of added chemical…a thing to explore, really. All good luck with a successful closed loop!

    • My doses are not particularly large, so the difference in performance came as quite a surprise.

      Generally, according to the literature, u200 concentrations have a slower absorption than their u100 cousins, with the exception of Humalog, which is about the same, so seeing better results can’t only be down to the size of the “pool”.

  4. Thanks, Tim – interesting as always. I hadn’t known about the U200 experiment, which is intriguing. What do you think about differences between that approach and the approach of mixing Lyumjev with Novolog or Humalog? Both go in the direction of less additive per insulin molecule, but differ in total volume of liquid injected for the same glucose-lowering effect.

    • This is the question I came to ask. I have a sample vial of Lyumjev and a Humalog KwikPen with 150 units in it. I’m thinking I’ll push 150 units of Lyumjev into the pen and fill my Omnipod the next couple times from that pen. In theory I should be getting a full dose of Humalog with 1/2 the additive per insulin molecule vs. straight U100 Lyumjev.
      But I’ve never used Lyumjev at all so I may well tolerate it just fine on its own.

  5. As always, greatly appreciate your research and sharing of results. My trial with Lyumjev was much LESS successful: while the infusion site irritation diminished after about 10 days, the delayed onset of action did not and I had to increase basal rates 10-25% to offset the delay. Overall, Lyumjev was slower to act than Humalog, significantly slower than Fiasp; it seemed like I had significant insulin resistance when taking Lyumjev. In reading the drug interactions, I wondered whether taking thyroid replacement hormone affected Lyumjev onset more than other insulins? Since many with T1D develop hypothyroidism, seems like the drug interaction may limit long-term use of Lyumjev?

  6. Lyumjev works fine your Keillor pen sucks after your halfway done with a pen it is very difficult to rest and get a full dosage. It’s like it sticks

Leave a Reply

Your email address will not be published.