Loop (iOS)

Loop is an open-source automated insulin delivery (AID) app that runs on the iPhone, built and maintained by the volunteer LoopKit community.¹ Unlike commercial AID, the app is not on the App Store — you compile it yourself from source onto your own device, which is the central fact of using it.¹

Platform and algorithm. Loop is iOS-only (it also runs on Apple Watch); there is no Android version — the equivalent Android project is the separate AndroidAPS.² Its algorithm is a model-predictive control (MPC) design that, every five minutes when a new sensor value arrives, forecasts glucose out to the insulin action duration using insulin-on-board, entered carbohydrates and a dynamic carbohydrate-absorption model that revises how fast a meal is actually being absorbed from the observed glucose response.³ This lineage is distinct from the OpenAPS/oref family that powers AndroidAPS and Trio.⁴ Loop 3 can dose by automatic micro-bolus (delivering a fraction of the recommended correction each cycle) rather than temp-basal only.³ Notably, Loop deliberately does not auto-adjust your insulin sensitivity the way OpenAPS "autosens" does — it trusts the therapy settings you give it, applying only a short-term retrospective correction for the last hour; meals work best when announced, though it is "fairly forgiving" of unannounced ones.³ That design choice favors predictability over maximal automation.

Supported hardware. Loop drives Omnipod DASH (Bluetooth, no radio bridge) and the older Omnipod Eros, several older Medtronic pumps, and Medtrum and Dana patch pumps.² Two things changed in mid-2026. First, Loop v3.14.2 (6 June 2026) replaced the two legacy pod drivers with OmnipodKit, a single unified Omnipod controller — a one-way move, so Omnipod users who build v3.14.2 cannot go back to an earlier version without replacing their pod.⁵ Second, the same release added Eversense E3 and Eversense 365 CGM support and brought Medtrum Nano (200U/300U) pump support into a tagged release; Medtrum Nano requires v3.14.2 or newer.⁵² Dana (Dana-i / DanaRS-v3) still requires building a feature branch rather than the released code.² For glucose Loop reads Dexcom G6/G7/ONE, European Libre 2 / Libre 2 Plus and Libre 1 (via transmitter), and Eversense — but not Libre 3 or the US Libre 2 directly.² Eros and Medtronic pumps need a RileyLink-class radio bridge; the newer Bluetooth pumps do not.²

Community and support. Loop has unusually deep documentation (LoopDocs) and a large volunteer support network — Loop and Learn, Facebook and Discord groups, and live sessions offer build help.⁶¹ More than 9,000 people were estimated to be using Loop by the time of a 2022 Stanford study.⁶

Legal and self-responsibility status. DIY Loop is not a regulated medical device; you build and run it at your own responsibility, and LoopDocs is explicit that you must know how to set up, operate and troubleshoot it.¹ Importantly, the Loop algorithm became the basis for Tidepool Loop, which the FDA cleared in January 2023 as the first interoperable automated glycemic controller (iAGC) supported by real-world evidence rather than a classical trial — the first regulatory clearance of an open-source AID algorithm.⁴⁷

Clinical evidence. In a prospective real-world study of 558 adults and children, Loop raised time-in-range from 67% to 73% and lowered HbA1c from 6.8% to 6.5% over six months, with no increase in severe hypoglycemia.⁸ Qualitative work with Loop users reports reduced management burden and better quality of life, alongside real setup and troubleshooting friction.⁶ (The randomized CREATE trial of open-source AID used the OpenAPS algorithm in AndroidAPS, not Loop, so it speaks to the open-source approach generally rather than to Loop specifically.⁴)

More recent work has started to place Loop next to commercial AID and to extend it to children. A 2026 study compared glucose management between open-source Loop and Tandem Control-IQ in adults with T1D — we cite it here only as evidence that such a head-to-head comparison now exists, because it was published as a letter without an abstract, and we will not put numbers on it we have not read.⁹ Separately, a single-centre study followed 50 children aged 2–18 who started Loop: over six months time-in-range rose from 68.3% to 72.7%, the share of children above the 70% time-in-range target rose from 46% to 66%, and HbA1c fell from 7.0% to 6.6% (in a smaller subset with HbA1c data), with no change in time spent low and no episodes of diabetic ketoacidosis.¹⁰ It is one centre and there is no control group, so read it as encouraging rather than definitive.

What's coming. The headline is Omnipod 5. Announced to the #WeAreNotWaiting community at D-Data 2026 (alongside the ADA Scientific Sessions in June), Omnipod 5 support for Loop and Trio has moved out of a small closed beta and into an open beta — but read that carefully. It runs on the dev branch, not the released code: you have to build the development branch to get it, it is aimed at experienced Loopers, it is not FDA-cleared, and it is not supported or endorsed by Insulet.¹¹ It arrives through OmnipodKit, the same unified open-source Omnipod driver that already ships in released Loop and covers Eros and DASH.¹¹ General release is dated by the project only as "when it's ready" — likely by the end of summer 2026 — so treat that as a target, not a promise.¹¹ (AndroidAPS developers are working on their own Omnipod 5 support, but have given no ETA; this beta is Loop and Trio.¹¹) Dana pump support, meanwhile, is still maturing on feature branches.² The bigger arc is convergence with the regulated world — Tidepool Loop's clearance opens a path for the DIY-born algorithm to reach people who can't or won't self-compile, while the open project keeps iterating on dosing strategies and hardware reach.⁷⁴

References

1. LoopKit community. LoopDocs — Loop FAQs (the app is not downloadable; you build it yourself and operate it at your own responsibility). Accessed 2026. https://loopkit.github.io/loopdocs/faqs/loop-faqs/ ↩ ↩² ↩³ ↩⁴

2. LoopKit community. LoopDocs — Compatible Pump and Compatible CGM (Omnipod DASH/Eros, Medtronic, Medtrum Nano on v3.14.2+, Dana on the feat/all-managers feature branch; Dexcom, Libre 2 Plus, Eversense; RileyLink requirements; Omnipod 5 available only by building the dev branch). Accessed 2026. https://loopkit.github.io/loopdocs/build/pump/ ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷

3. LoopKit community. LoopDocs — Algorithm overview, Dynamic Carbs, Bolus recommendations & Algorithm FAQs (model-predictive control; dynamic carb absorption; automatic bolus; no autosens-style sensitivity learning). Accessed 2026. https://loopkit.github.io/loopdocs/operation/algorithm/overview/ ↩ ↩² ↩³

4. Braune K, Hussain S, Lal R. The First Regulatory Clearance of an Open-Source Automated Insulin Delivery Algorithm. Journal of Diabetes Science and Technology (2023); 17(5):1139–1141. According to PubMed. https://pmc.ncbi.nlm.nih.gov/articles/PMC10563523/ (DOI) ↩ ↩² ↩³ ↩⁴

5. LoopKit community. LoopDocs — Releases. Loop v3.14.2 (6 June 2026) added Eversense E3 and Eversense 365 CGM support and Medtrum Nano patch-pump support, and replaced the legacy pod managers with a unified OmnipodKit controller — noting that "Omnipod Users cannot return to v3.14.0 after building v3.14.2 without replacing their Pod." v3.14.0 (14 May 2026) added Pod Keep Alive for iPhone 16 / 17e. https://loopkit.github.io/loopdocs/version/releases/ ↩ ↩²

6. Suttiratana SC, Wong JJ, Lanning MS, et al. Qualitative Study of User Experiences with Loop, an Open-Source Automated Insulin Delivery System. Diabetes Technology & Therapeutics (2022); 24(6):416–423. According to PubMed. https://pmc.ncbi.nlm.nih.gov/articles/PMC9208860/ (DOI) ↩ ↩² ↩³

7. Tidepool. Tidepool Loop has received FDA Clearance! (January 2023; first FDA-cleared interoperable automated glycemic controller built on the open-source Loop algorithm). https://www.tidepool.org/blog/tidepool-loop-has-received-fda-clearance ↩ ↩²

8. Lum JW, Bailey RJ, Barnes-Lomen V, et al. A Real-World Prospective Study of the Safety and Effectiveness of the Loop Open Source Automated Insulin Delivery System. Diabetes Technology & Therapeutics (2021); 23(5):367–375. According to PubMed. https://pmc.ncbi.nlm.nih.gov/articles/PMC8080906/ (DOI) ↩

9. Wu Z, Lebbar M, Lal R, Bonhoure A, Messier V, Nguyen É, Boudreau V, Brazeau AS, Rabasa-Lhoret R. Comparison of Glucose Management Between Open-Source Loop and Tandem Control-IQ Automated Insulin Delivery Systems in Adults With Type 1 Diabetes. Diabetes, Obesity and Metabolism (2026); 28(6):5394–5398. Published as a letter; no abstract available, so we report its existence only. According to PubMed. https://pubmed.ncbi.nlm.nih.gov/41873003/ ↩

10. Ugur Kaval A, et al. Use of the Loop Open-Source Automated Insulin Delivery System in Children with Type 1 Diabetes: Six-Month Results from a Single Center. Hormone Research in Paediatrics (2026; epub 27 January 2026). Fifty children aged 2–18 starting Loop at a single centre; time-in-range 68.3% → 72.7% at six months (p=0.003), HbA1c 7.0% → 6.6% (p=0.006, limited sample), time-below-range unchanged, no DKA. According to PubMed. https://pubmed.ncbi.nlm.nih.gov/41591961/ ↩

11. Nightscout / open-source AID community. Omnipod 5 — Open-Source AID (last updated 2 July 2026). Announced at D-Data 2026; Omnipod 5 support "is now in an open beta for experienced Loopers or Trioneers, and will be available to all users later this summer", delivered via OmnipodKit, "a new, unified open-source Omnipod driver". Full release dated only as "When it's ready™ — likely by the end of the summer"; AndroidAPS support is in progress with no ETA. Not FDA-cleared; not supported by Insulet. https://nightscout.github.io/omnipod-five/ ↩ ↩² ↩³ ↩⁴