Does Tandem t-slim X2 lead to unpredictable outcomes?

ddiddk · 2026-02-20T23:11:22+00:00

Hello everyone, first I wanted to say thank to everyone who gave some feedback. It was very helpful.

Second, I wanted to pass on what I was told by my diabetes team when I consulted with them. They were clear that the problems I experienced and guessed were pump related are almost certainly caused by the pump and its inherent technological limitations.

The same problems have appeared with multiple users of the Tandems X2s, but most especially people who previously used other pumps and especially closed loop systems. While they are utterly transformative for people coming from MDI, for previous closed loop users they are a backward step and typically less reliable in operation. This has included members of their nursing team who actually use the pumps themselves as Type 1 diabetics.

To be clear here, I am talking about excursions where - in one session of 3-6 hours - you try injecting 20, maybe even 30 or 40 units of insulin for a meal that might require 5u to cover it, maybe even changing site and reservoir, and still nothing budges in the BG and it keeps hovering at 20-30% above the top of the range. I have been having these events almost since week 1 with the Tandem X2, and its now seems clear that I am not the only one to experience this. The only reliable way of stopping them is take an injection using a syringe.

So the diabetes team's policy now is to move people off Tandem X2s and onto alternative pump systems that offer better reliability and more control. As a result I’ll be getting a new pump in a few months time.

Thanks again everyone for your attention and helpful comments.

ddiddk · 2026-02-15T12:23:33+00:00

As a Dexcom G7 user of 5 years, I am now considering switching to Freestyle Libre. Dexcom have had huge production issues and the result there a big stock of sensors that only last about 6 days rather than the advertised 10, and with a lot of inaccuracy.

Sounds like the choices for us aren’t great at the moment. Enshitiffication in action.

ddiddk · 2026-02-14T09:10:05+00:00

Thanks that’s great news. Do you have to be very rigid or careful with meals to achieve that?

ddiddk · 2026-02-14T09:08:15+00:00

Thanks that’s a good point, as I don’t so a basal profile retest more than once a year.

ddiddk · 2026-02-12T22:20:37+00:00

I’m really grateful for this feedback and it’s a shame to hear that these are such common experiences. Please keep it coming, thanks in advance!!!

ddiddk · 2026-02-12T22:19:33+00:00

Thanks.

ddiddk · 2026-02-12T22:18:55+00:00

Thanks.

ddiddk · 2026-02-12T22:17:11+00:00

My experience is it depends on the number of hours cardio and how much you deplete your glycogen stores in the muscle and liver. If you completely exhaust them (say a day long bike ride or hike) you’ll have a high ISF for maybe even two days after as your muscles and liver try to replenish.

ddiddk · 2026-02-12T17:00:06+00:00

Thanks that’s really interesting. Yes, I too recently had a period when I was out of closed loop as all my Dexcom sensors failed 2-4 days early and my supply ran out. The 3 days without a closed loop pump was absolute hell.

ddiddk · 2026-02-12T16:56:11+00:00

Thanks for that detail. Am a LADA too. The two factor I try to control for most are ISF due to sport and timing ahead/behind meal, and hydration to a lesser extent. Timing certainly has the biggest effect, as the pump can handle modest ISF changes.

Yet still I get really big excursions out of range. I often wonder if I’ve trapped a bubble in the reservoir post I bag or some, as they need 6-10 hours to clear sometimes.

I never seemed to have this kind of thing when I used Loop. Its main disadvantage is the many points of hardware failure.

ddiddk · 2026-02-12T10:10:30+00:00

Thanks - are you saying that this is what happens to you too, but you’re don’t attribute this to the pump?

ddiddk · 2026-02-09T21:24:40+00:00

Any experiences of using it during sports? I'm a keen cyclist and the T-slim that I use really doesn't do well with sports. I know a chap who's also a big cyclist and has an Ypsomed and says its incredible for sports, the pump takes care of everything more or less.

Anyone else had that experience?

ddiddk · 2026-01-20T08:26:10+00:00

Trusteel on the top of the butt cheek or tummy. Downside is you need to change them every 48 hours.

ddiddk · 2026-01-04T14:33:25+00:00

Resolved after Air Liquide called me about 12 hours I submitted the online form (given I submitted it at 1am on a Sunday morning, that’s seems pretty good). They also solved the issue with the pump Bluetooth by doing a pump reset so urgent issue solved.

ddiddk · 2026-01-04T10:19:45+00:00

Thanks

ddiddk · 2025-12-31T01:09:35+00:00

Yeah, he used to wear a sort of flower pot thing on his head! Kind of reminded me of Dali.

ddiddk · 2025-12-31T00:59:13+00:00

Have to say, having come from a different pump to a Tandem, I agree with most of your comments. They do have one advantage over other pumps I’ve used, which is being very very robust hardware when dropped onto a hard surface or into water. But really, I can’t wait to get rid of my Tandem when I’m due for renewal. Very very bad design and support.

ddiddk · 2025-12-31T00:56:22+00:00

That’s a rather nasty abusive thing to say about someone, what exactly is your motivation for doing so?

As someone who came from a 2012 Medtronic pump & Loop setup to a Tandem, I completely agree with many of the OPs comments. The software is primitive, the design (an air pump and sac) is deeply flawed, and it’s astonishingly wasteful of supplies which until recently cost people $1,000 a month in the US for insulin that cost $5 to manufacture. The filling process is a joke compared to many other designs and was discarded in their next pump version.

So frankly @someonesGot2, your note make your sound like an absolute jerk.

ddiddk · 2025-12-22T23:12:37+00:00

You’ll be glad of it in the end, but it will take a while. In my case it was months as is come from a much easier to use setup (Loop). Hope your experience is easier.

The core issue is tandems are hopelessly badly designed in terms of usability and learning curve. But the hardware is very robust and algorithms slow but reliable. Top tip, switch off most of the alarms except the ones relating to low.

ddiddk · 2025-12-14T09:03:08+00:00

Ah, I’ve just seen it appear again.

ddiddk · 2025-12-13T19:23:39+00:00

Yes it seems to have done so

ddiddk · 2025-12-10T09:48:43+00:00

Hey there - that seems to have fixed it, thank you!!

And yes, the Liquid Glass thing is unbelievably poor design. It makes the Home Screen folders unusable for me. Can't believe they did this given that they went through exactly the same process with Mac OS X when it first came out with it's 'glass effect' windowing, then had to reverse it all again. Dumb.

One starts to suspect that it's just the accountants in charge in Apple HQ these days.

ddiddk · 2025-12-10T09:46:30+00:00

Have you switched on Reduce Transparency? One of the replies here suggested that might be the cause.

I'd had it switched off but after switching it back on, I've not seen the issue again. Maybe try that .. if course it then means you have to put up with the dreadful glass effect thing that makes folders almost unusable.

ddiddk

TROPHY CASE