Thinking of Starting Loop?

What is Loop?

Loop is an app you build yourself and load on your iPhone (or iPod) that uses a compatible continuous glucose monitor (CGM) and a compatible pump.  While there are several compatible CGMs and pumps, most Loopers are currently using Dexcom as their CGM and are quickly migrating from Dexcom Eros to DASH pods if they want a tubeless option. For those who prefer tubes, older Medtronic pumps are the only option.

Put simply, Loop makes dosing decisions every 5 minutes, so that you don’t have to.

What Should I Expect from this Starting Loop Series?

Many potential Loopers follow along on FaceBook, read LoopDocs and watch our YouTube Channel and are still not sure where to start.  The goal of this series is to help you can move from lurking to Looping by breaking the information into smaller bite-sized pieces.

Loop is a Do-It-Yourself (DIY) project but not a Do-It-Alone project.  There is a wonderful community of mentors happy to help.

We hope you find these articles informative and helpful as you begin your Loop journey.

Is Loop for Me?

Loop requires a substantial commitment to learning and understanding the technology, processes, algorithms, and troubleshooting flows.

Loop is NOT for everyone. But everyone who wants to Loop can find help from many volunteers in the Looping community.

Read this introduction, decide if you want to continue, and, if you do, welcome aboard.

What You do NOT Need to Loop:

  • You do not need to be a computer scientist to build and run Loop
  • You do not even need to understand how to set the time on your VCR
  • You do not need a Mac computer.  You can now build using a Mac, PC, tablet or phone.

What you DO Need to Build and Use Loop:

  • You need to be able to read and follow instructions
  • You need to make a commitment to carefully test your settings and adjust them
  • You need to make a commitment to coming back to the support forums on a regular basis to see if there are any important safety updates
  • You need to know how to troubleshoot and where to find the most current troubleshooting information
  • You need to know how to turn-off auto-updating on your phone iOS

You may notice there is a lot of “You” in the above. That is because you should not Loop unless you commit to staying up-to-date on Loop. Best practice: at least once a week, you should be going to your favorite support forum and reading the posts, visiting the Loop and Learn Home Page and reading the Announcements, or signing up for the Newsletter.

Commercial Options:

If, after reading the documentation here, you decide building Do-It-Yourself Loop is not for you, THAT’S OKAY!

There are other options available now. Medtronic was first to market with a hybrid closed loop using their pumps and sensors. Control-IQ and Basal-IQ are available for the T-Slim pumps from Tandem Diabetes. Insulet has their version of hybrid closed loop with the Omnipod 5.

Note: while both Loop and other DIY choices use Eros or DASH pods; the Omnipod 5 pods are different and there are no DIY solutions that use those pods.

If you are weighing the pros and cons of Loop compared to a commercial system, before going any further, check out these blogs written by two of the community’s most experienced Loopers:

We also have a YouTube Playlist on Omnipod 5.

Not interested in investing in the Apple ecosystem?

There are also Android options. The Android and commercial options are outside the scope of this Starting Loop series.  Which DIY Algorithm to Choose? highlights the differences among the various options and provides links to Android APS, as well as another iPhone option based upon the same algorithim as Android APS.


You are completely responsible for your own technology and settings decisions.

  • Do not pay someone to build Loop for you
  • Do not have it installed for you at a “Build Party”

You need to have all the bits and pieces available to rebuild it, if necessary, and you need to understand how to do that build with limited hand holding.

Loop is experimental. Loop is not approved for therapy by any official government agency. In some countries, you can get yourself into serious legal trouble for helping someone Loop.

Loop is only as good as your CGM.  If your sensor is noisy or you do not trust the readings for any reason – please OPEN your Loop.  You can still use your phone to control your pump manually, but Loop will not automatically give insulin (other than scheduled basal) without your explicit command.

You take full responsibility for building and running this system and you do so at your own risk!

Your Settings are Critical for Successful Use of Loop

If you are not comfortable figuring out your own basal rates, carb ratios, insulin sensitivity, and refining those on a somewhat regular basis, then Loop is not for you – yet.  But once again, if you’re willing to do the work, there are lots of mentors available to help you.

You can count on your fingers the number of doctors in the US who are capable of properly adjusting settings for Loop.  You can probably count on your fingers and toes the number worldwide who can successfully help you with Loop settings.  Be sure to check out our list of DIY Friendly Healthcare Providers.  If you are not familiar with books such as “Using Insulin,” “Pumping Insulin,” “Think Like a Pancreas,” “Sugar Surfing,” or other similar methods of figuring out and adjusting your own settings, you will need to do some reading, learning, and testing before you can be successful with Loop.  LoopTips has Settings Overview and Adjustment sections well worth your time.  Note that LoopTips was written several years ago and many features of Loop have been upgraded since then. 

There are people who have tried to Loop and have decided it was not for them (that’s OKAY).  The most common reasons that people will fail in their Loop attempts are:

  • Not understanding the algorithm-based control system (more explanations later)
  • Getting confused by settings and not understanding their interactions
  • Not realizing that insulin has a very long tail (duration of action); Loop uses this in its predictions
  • Failure to stay informed about Announcements in the Looped community
  • Having someone else build Loop without understanding it themselves

It is a mistake to find someone to build Loop for you.  You need to take the time and expend the brainpower to understand the fundamental concepts of what is being built.

History and background

If you’re interested in the history and some technical details about Loop, here are a few interesting articles:

There are several different flavors of DIY artificial pancreas systems (APS) and one of the founders of OpenAPS recently published this book:

Which DIY Algorithm to Choose? provides a great synopsis of the different DIY options.

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