Experiences?: Lyumjev, Tandem X2, and Closed-Loop

I just started using Lyumjev, and I just love it. I was using Fiasp before, but eventually, it started causing occlusions in my pump. I learned that it’s literally because of its chemical composition, it can crystalize in the cartridge. I went on MDI to use up the Fiasp that I had, and, thankfully, I got a new job with insurance that covers Lyumjev. I’ve been back to pumping and using Lyumjev now since about late March.

I just remembered as I was typing this that I now have a Dexcom G6 and, duh, I can turn on the basal IQ. :blush:

I’m stalling with the closed-loop because I notice that because the pump is set for Humalog, it thinks I have basal insulin active in my system when I don’t. As far as I know, Tandem is really dragging with giving us the option to update to faster-acting insulins.

For those of you who are using a Tandem X2 with Lyumjev can you share how it’s working for you? Since I literally just turned basal IQ on now, I’ll get used to that first.

Thanks, all!


The profile of it looks so similar to novolog and humalog, I’m surprised it is different enough to mess up your basal iq.
But maybe you need to adjust your settings a little.
I tried pumping fiasp with one bottle that I got from my doctor.
It was good and didn’t have problems, I cut my prebolus time.

Maybe you can upgrade to control iq , it might work better for you.

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I still need to set up Basal IQ, so there is no rush. I tried, but it didn’t take. I also am on the last 10 days with my current transmitter, so I can wait it out until I have a fresh one. I got the “this is the last time you can use this transmitter” warning when I attached the current sensor that I’m wearing. I can just wait it out a few more days, as I don’t have the bandwidth to fret over Dexcom’s forced stops. (Annoyed…I’m going to be annoyed with this change for a while, but I know they need to make a profit.)

Hopefully, it won’t be too bad. I’ll road test it with the Basal IQ and then shift to Control IQ once I feel comfortable.

I LOVE Lyumjev. I have never been able to use Novolog. So slow acting. FIASP was a disaster in Tandem pump and I didn’t think it was any faster than Novolog. I used to use Humalog and Symlin. I had to give up Symlin because no Part D plans cover it and after three months of using Victoza I went in the donut hole and it was going to cost $700. But on Lyumjev alone I am in target 80-95% of the time and I bolus right before the meal. It does burn/itch a little with boulses but small price to pay. No post Meal spikes beyond 180 and turns around really quickly DIA still about 4 hours. Don’t be afraid of DIA on control IQ. It r3ally isn’t five hours. Because when it changes the basal up or down it adds or subtracts the insulin on board so it’s always a moving target. Just trust it when doing meal and bonus corrections.

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I use lyumjev in a Tamdem pump with no problems. Lyumjev is noticeably faster than Humalog. It was like Humalog stopped working. I do NOT use Control IQ or Basel IQ and do recommend them. If I were to use Control IQ, my A1c would get worse (5.7). I have considered using Basel IQ but after 3 years of Dexcom (5-6) I do not trust it. I don’t want to stop using it but am finding frequent discrepancies between Contour and Dexcom. Worst case is 80 points difference. I’m not willing to have Dexcom as a part of a closed loop system. I have this figured out. 36 years on pump and 55 years as T1d. :grin::four_leaf_clover:

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I have a tandem pump and I use control iq. I have the setting tweaked a bit to get tighter control. My last a1c was 5.4, previous to that it was 5.5. Before I started using the ciq feature I was at 6.4.
My dexcom seems pretty spot on. I know it’s different for everyone, but I hardly even double check it anymore.

Yesterday I got a 54 on my dexcom and I didn’t believe it because I felt fine, but my finger stick was 57.

Even the finger stick meters are ± 15 percent. So it’s almost pointless to compare them. That being said it’s always less than 10 percent unless my sensor is bad.


Good points, Penn. I currently have a 6.0 a1c, and that is a concern. There is someone in a type 1 group that I’m in. Her a1cs are amazing, and she won’t switch to closed loop. My endo recommends it though. I trust him, so we’ll see how this goes.

Yeah. I think that I’m going to go in. I’ve got to figure out how to set up the Basal IQ on my pump first. As I wrote earlier, my transmitter is about to die, so I’ll start with a fresh one tonight and will try to set up Basal IQ. Once I get that going, it will be a slow march to Control IQ.

Oh, you were at 57 and didn’t feel it? Yikes. My hypo-awareness fades in and out, and, right now, I’m hypo aware. I hope it comes back for you too.


You know that Basal IQ and Control IQ are separate pumps right? You can’t switch back and forth between them?

My A1C went to 6.2 on control,IQ with humalog. It went to 5.8 on control IQ with Lyumjev and I keep it in sleep mode all day for tighter target range. Sensors always have lag time when change is going on. That doesn’t mean it isn’t accurate. It’s not measuring blood. It still tells the pump and you what it needs to know. 48 years with diabetes 28 years on a pump 10 years on Dexcom

You can go from basal iq to control iq with a software upgrade.
You can’t go backwards from ciq to biq

Not true. :slightly_smiling_face: It’s the same pump: Tandem X2. I just need to upgrade the software.

I had an appointment with my endo today and told him I’m going to stick with Basal IQ for a bit more. I might not update the software…see below. (I probably will though.)

The problem with Tandem is it’s one and done. Once you upgrade, you can’t roll back the software. I found this out the hard way when I got this pump new and was still using a Dexcom G5. I had to wait until I got a G6 to use Basal-IQ because you can’t roll the software back. That’s annoying.

Why am I a little hesitant?

My a1c is now 5.7, and that’s with 3.2% of my time dealing with lows and most of my time, 60%, in range. I’ve got to see if I can slice some time off the highs. I’m fine with 35% higher vs. a larger amount of time low. Since these numbers are really good, we’ll see. I’m a bit leery because I heard the range for Control-IQ might actually take my average back up. I need to do some research on that.

I’ve had ControlIQ long enough to have two A1Cs. My average BS did go up, but my a1c stayed in the same range (5.7 and 5.4). I attribute that to more stable bs (less highs and lows) with ControlIQ and excellent overnight control. So for me the CIQ higher target really had no impact on my A1C.

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My ciq works great for me and I’ve also settled into the mid 5 a1c range.
In reality though I correct highs before the algorithm does, so my pump hardly ever blouses on its own.
That’s really the whole benefit of ciq.
I never tried biq. For me it would probably be similar since I try to stay on it.
My TIR is usually in the 90s some days though I can get 100%
I managed 8 days in a row at 100%.
It was an accomplishment.


This is good to know. That’s tracks with what I’ve noticed. With Basal-IQ my lows are kept in check, so the only time I have issues is if I go high when I’m asleep. I thought about it the other day when I woke up with high blood sugar: had I had Control-IQ it would have been in check.

Yeah, my time in range averages around the high 70th percentile.

Thanks for confirming that, Jim26 and Timothy. I’m feeling better about this. If I don’t get through the Control-IQ training in the next few weeks, I’ll make sure to do it when I take a few days off for vacation.

Hey @Bobbie2,

How do your nighttime glucose levels looks? It sounds like you’re doing what I am currently looking into doing - that is I want to use Lyumjev in a Tandem pump. I primarily want to use Control IQ at night. I’m not sure if I’ll use it during the day. Can you turn it off?

I don’t like the idea of the pump correcting a 90 up to 112.5. It is unnecessary. Do you know if there is a workaround?

It looks like basal iq will only reduce basal if you’re predicted to be below 80. Maybe that is a better fit for me.


Using sleep mode all day is the only work around for a tighter range. My sugars are 90-109 all night long. Lyumjev turns me around so much faster than Humalog it’s amaZing and I can bolus right before eating and not go above 170 and then start to come back down quickly. It burns and causes some site issues tho. Nothing I can’t live with.


You can turn control IQ Off but it doesn’t go to basal iq. It’s one or the other. If you turn it off you have no hypoglycemia prevention. I would try sleep mode first but you have to be aware of Insulin on Board from increased basal when you do that. All increases or decreases in basal are counted or subtracted from IOB


That’s very helpful. Thank you. I hope I don’t have site issues!

How did it go with Lyumjev and the Tandem pump?

I know it´s an old post, but in case you see this I would be interested.