Let’s Do The Twiist!
By Gary Scheiner, MS, CDCES, FADCES
As is tradition, whenever something new is introduced in the diabetes world, I like to give it a try. In this case, nobody had to “twiist” my arm. The automated insulin delivery (AID) system I tried is very similar to the open-source (O-S) “Looping” system I’ve utilized successfully for many years.
Twiisting: the Facts
The product of Sequel Med Tech, Twiist is an insulin pump that integrates with the Libre 3+ continuous glucose monitor (CGM) and Tidepool Loop app, rebranded as “Twiist Loop.” 
What is truly new and unique is that it utilizes the highly-regarded open-source/DIY Loop app concept without the user having to build and maintain the app on their own. Tidepool went to the trouble to curate the O-S Loop app in a way that was acceptable (and approved) by the US Food and Drug Administration, so users can simply install it right off the app store. The other unique aspect of the system is the pump itself. The Twiist pump consists of two parts: a reusable base, which contains all the hardware and electronics, and a disposable cassette that holds the insulin. The two parts are twisted together and apart, akin to a double-stuff Oreo cookie. This keeps costs down relative to a fully-disposable patch pump. The Twiist AID System also includes an app called Twiist Insight, which allows loved ones to follow the user’s status in real time.
A tubed pump with a Leur-lock connection, Twiist utilizes the Cleo-90 infusion set, which was introduced by Deltec more than a decade ago for use with the beloved Cozmo pump, which was driven to extinction by the lawyers at a Medical device company who shall reMain naMeless. Data from the Twiist AID System is synced with Tidepool for generating reports for users and their clinicians. And, as mentioned earlier, CGM data is provided by the Libre 3+ sensor from Abbott. Sequel already has an agreement in place with Senseonics to sync with the implantable Eversense 365 sensor, but the logistics won’t be worked out until sometime in 2026.
My Twiisted Impression
Overall, I have been quite pleased with the overall system. The pump is compact and easy to use. The Twiist Loop app makes programming fairly simple, and the insulin-adjustment algorithm works extremely well. And the Libre 3+ sensor has been surprisingly reliable. Here are some specific features that give Twiist an advantage over most other AID systems.
Twiist ™ utilizes the highly-regarded open-source/DIY Loop app concept without the user having to build and maintain the app on their own, but what do real world users think?
IN EPISODE 75 of Think Like a Pancreas—The Podcast, Integrated Diabetes Services founder Gary Scheiner sits down with DiabeTech host Justin Eastzer to discuss their experiences using Sequel Med Tech’s Twiist™ insulin pump. They take a deep dive into the unique “Loop” algorithm that powers the pump, the unique 6-hour predictive capabilities, and how it compares to other automated insulin delivery (AID) systems. Gary and Justin also share their thoughts on alarms, time in range, and the return of the Cleo luer lock infusion set.
Unique Pump Features:
- 300-unit insulin capacity
- Small. lightweight design with no sharp edges
- On-pump manual bolus button
- Rapid occlusion detection
Unique App/Algorithm Features:
- Superior Loop-based algorithm which balances active insulin against active carbs to make accurate long-term glucose predictions
- Wide-range for target glucose (87-180 mg/dl)
- Allows user to adjust meal “absorption time” for quickly- or slowly-digesting foods
- Ability to back-enter or advance-enter food intake
- Algorithm applies the user’s preferred basal settings as its starting point before making adjustments
- Customizable target for physical activity (up to 250 mg/dl)
- Customizable temporary “tight” target (as low as 67 mg/dl) for use prior to meals
- Apple Watch compatibility
- Although insurance coverage can vary, out-of-pocket costs for the Twiist AID system tend to be lower than with most other systems. In many cases, there is no up-front cost for the durable component of the pump. The Twiist disposables are billed through pharmacy benefits, resulting in a fixed, modest monthly cost for supplies.
Of course, what goes up must come down. There are a number of system qualities that come up short compared to other AID systems.
Pump Negatives:
- There are a LOT of parts (8, plus insulin and CGM), which can be a challenge for anyone with limited vision or dexterity, as well as anyone who does a lot of traveling.
- There are also a LOT of steps involved in changing out the insulin cassette and infusion set. I counted 32. Even after several times to practice, it still takes me more than 9 minutes to complete the process.
- Only one infusion set option: A 90-degree 6mm flexible cannula with 24” tubing.
- The adhesive base on the infusion set is small and not very strong. Adhesive wipes and/or overtape are usually required to keep the set from falling off. And sometimes, the cannula pulls out of the skin when the inserter is pulled away during the insertion process.
- On-pump manual bolus button only delivers in 1-unit increments.
- No site-change reminder.
- User must manually enter the amount of insulin used to fill the pump.
- Very small port hole for injecting insulin into the pump.
- Alerts are quite loud; no way to adjust the volume.
- No vibrate option on the pump.
Sensor & App Negatives:
- CGM cannot be calibrated.
- System currently works only on iPhone (android compatibility is in the works).
- The glucose alert options are very limited (just basic high/low).
- Cannot use Libre app while CGM is synced with Twiist.
- Cannot link the app to a sensor mid-session. Must discard the old sensor and start a new one.
- 1-hour sensor warmup time with no workaround.
- CGM tends to underestimate glucose levels in the low (and near-low) range; false low alerts are common.
- Can only visualize 1-hr and 10-hr trendgraphs.
- The trendgraph display on the Twiist Loop home screen does not show the target glucose zone, and the glucose scale is narrow. This over-emphasizes subtle rises and falls and may contribute to over-reaction by some users. See the example below with images comparing Twiist’s 10-hr trendgraph and Dexcom’s 12-hr trendgraph taken at the same time, based on the same data.
- No vibrate option on the pump.
Twiist trendgraph (solid blue line): appears to show significant rises and falls.
Dexcom trendgraph: Shows a single peak before bedtime followed by steady glucose through the night.
LOOP vs LOOP
So, how does the Twiist AID System compare to the Loop system I’ve grown accustomed to using over the past several years?
For those who don’t know, Loop features the latest version of the Loop app, (typically) the Dexcom G6 or G7 sensor, and (in most cases) the OmniPod Dash pump.
Areas where the Twiist AID System is superior to Open-Source (O-S) Loop:
- No Building Required. Twiist Loop comes pre-assembled and ready to install right from the app store. No special equipment, developer licenses, OS updates or extra time required.
- Phone Support. O-S Loop users support each other nicely through the online community. But nothing beats the ability to call and speak with a technical support expert 24/7.
- Automatic Updates. Both systems offer upgrades/updates free of charge. However, software/system updates must be initiated and performed by users of O-S Loop, whereas Twiist users receive their updates effortlessly.
- Training. Twiist users receive complete system training by company clinical representatives or certified trainers. O-S Loop is “LIY” (learn-it-yourself), unless you have clinicians like those at Integrated Diabetes Services at your disposal.
- Greater Insulin Capacity. The Twiist pump holds 50% more insulin than OmniPod Dash (40% more after priming the tubing). This is a definite plus for those who require more than 60 units per day.
- Temp Basal Option. When closed loop is not “on”, Twiist users have the ability to set temporary basal rates for up to 24 hours.
Areas where O-S Loop is superior:
- Tubeless Pump. O-S Loop is compatible with the tubeless OmniPod Dash pump, which tends to create fewer obstacles and inconveniences for pump users.
- Modern Features. The Twiist Loop app is based on the O-S Loop, but it was created several years ago. Since then O-S Loop has undergone a number of improvements. These are some of the things you can do with O-S Loop that you can’t do with the current version of Twiist Loop:
- Program “custom presets” (temporary overrides), with user-chosen glucose targets and percent changes to usual delivery for preferred time intervals.
- Use an “auto-bolus” dosing strategy for preventing/correcting elevated glucose levels (Tidepool Loop only makes automated adjustments to basal delivery).
- Create and choose from different 24-hour basal “profiles”.
- Connect to Nightscout, which enables both data-sharing and some system control by loved ones, and also generates a variety of unique and useful reports.
- CGM Selection. At this time, Twiist users only have one CGM option: Libre 3+. O-S Loop users may choose Dexcom G6/G7/One as well as Libre 2/3 and Medtronic Enlite.
- This may sound picky, but manually entering a bolus dose in Twiist Loop requires entries in hundredths of a unit. For 2 units, you must enter 2.00 (2-0-0). With O-S Loop, you can just tap “2”. I know, it’s a safety thing to prevent accidental over-dosing, but for experienced users, all that extra button-pushing is annoying.
Twiist-Off (Re)Cap
Clearly, the Twiist AID System has a lot going for it.
From the pump form-factor to the pricing model to use of the sought-after Loop app/algorithm, Twiist will improve the lives of many, many people with diabetes. I’ve enjoyed using it for the past several weeks.
But I do miss the simplicity/convenience of the tubeless OmniPod pump, the alert customization features of the Dexcom CGM, and many of the advanced programming options that are available only in the O-S Loop app.
