To Loop or Not to Loop?

What is the Loop?

The Loop is a do-it-yourself (DIY) automatic insulin delivery system that involves three components: an Apple computer for building apps for iPhones and Apple watches, an old Medtronic pump or Omnipod, and a device called a RileyLink.  Several other systems, such as OpenAPS and AndroidAPS, are available, but the Loop is the most popular and the subject of this article.  Complete instructions for creating the Loop can be found at

A DIY system may be intimidating for some people to such a degree that they may believe this is something out of their reach.  However, my experience through my wife’s use of the Loop and helping others to start using the Loop leads me to believe this system would be beneficial to many people.  Using the Loop has brought my wife’s typical time in range numbers to between 90% and 95%.  Hopefully answering the following questions will explain the requirements of setting up and using the Loop to remove any mystery of the device that you may have.

Who should consider using the Loop? 

Anyone who is actively trying to manage their condition and is knowledgeable about their diabetes.  The Loop is not a magic pill that will solve all your management issues by itself, but it is a fabulous tool for helping you manage your diabetes. People using the Loop can make adjustments that will cause the Loop to be more or less aggressive in correcting their blood glucose levels.  After over 30 years of managing her diabetes, my wife feels like she is “cheating” using the Loop.

How does the Loop work? 

The Loop transmits temporary basals to your pump depending on your blood glucose readings, trends from your CGM, and your Loop settings.  In the simplest terms, the Loop increases your basal rate up to your maximum basal rate when it detects your blood glucose is trending high, or it decreases your basal rate potentially to the point of stopping all insulin delivery altogether when it detects your blood glucose trending low.

What is needed to use the Loop?

The items needed for a Loop system are a compatible pump, a continuous glucose monitor (CGM), an iPhone, and a RileyLink.  The pump must be an OmniPod (not the Dash) or an older version Medtronic.  The CGM most typically is the Dexcom with the appropriate Dexcom app loaded on your iPhone.  The iPhone must have iOS 12.2 or newer.  A 6th generation or newer iPod Touch with the same iOS requirement may be substituted for the iPhone.  More details on the specific compatible devices and how to order a RileyLink can be found at the websites listed at the bottom of this article.

What is needed to build the Loop app? 

To build the Loop app for an iPhone, an Apple computer running High Sierra macOS 10.13.4 or higher is required.  Xcode and Homebrew must be installed onto the computer, and an Apple Developer Account must be set up.  The Loop code can then be downloaded to the computer to build the Loop app.  The Loop app is then downloaded from the computer to the iPhone.   The Loop app on your iPhone is now ready to be set up using your specific pump, CGM, and settings.

Will any functionality of the pump be lost using the Loop? 

The Loop app on your iPhone will allow you to control your pump just as you have in the past.  The Loop app also has an open loop feature that allows you complete control of your pump.

What is the RileyLink for? 

The RileyLink links your iPhone to your pump.  The RileyLink includes an antenna to receive and transmit information to your pump and communicates with your iPhone via Bluetooth.  The RileyLinks are different for the OmniPod and the Medtronic pumps.  The RileyLink should be charged every day and must remain in close proximity to your pump.  Most Loop users charge both their iPhone and RileyLink on their nightstand every night.

Can I use the Loop with my Android phone? 

No, but AndroidAPS is specifically for Android users.  If you prefer to use the Loop while maintaining your Android phone, you just need to obtain a compatible iPhone or iPod Touch.  This iPhone does not need to have cellular service to use the Loop.  If you can get an iPhone or have an old iPhone in a drawer, you can use the Loop.

How much does it cost to use the Loop? 

Assuming you have a compatible pump, a compatible CGM, a compatible iPhone, and an Apple computer, your only costs would be a RileyLink for $150 and a paid Apple Developer Account for $100 per year to avoid having to reload the Loop app every seven days.   Compatible Medtronic pumps can be found online at various prices if one is needed.

Does the Loop just add my iPhone to the devices I need to carry to manage my diabetes? 

With the Loop app on your iPhone you will no longer need to carry your OmniPod PDA, if applicable, as it will not be functioning to control your pod.  Hopefully, you already stopped carrying your Dexcom receiver when you installed the Dexcom app on your phone.

What if I am still intimidated by doing this by myself or do not have an Apple computer? 

Take a look at my website

I believe using the Loop is a great thing for people with diabetes.  For my wife, the drastic highs and lows have been practically eliminated, nighttime lows are essentially gone, the feeling/anxiety of having to constantly monitor her blood sugars has been reduced, fewer alarms are sounding, her A1c has lowered and her time in range has increased, and, in general, managing her diabetes has been made easier.  Anyone serious about managing their diabetes and wanting to use the Loop should not be hindered by a lack of confidence in being able to build the DIY system or the lack of an Apple computer.

If you have questions or would like additional information, please feel free to email me at  Also, if you are having difficulties using the Loop or have stopped using it all together, contact me as I may be able to help you.

Compatible pump information:

Compatible CGM information:

Compatible iPhone information:

RileyLink order information:


To read about Dr. Edelman’s looping experience with the Omnipod, click here.

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