[Last Updated 3/5/2017]

Dexcom released their highly-anticipated G5 continuous glucose monitor (CGM) for diabetes in September 2015. As the first CGM (ever!) that transmits glucose data directly to the iPhone, there’s been a lot of excitement about the revolutionary new device. There’s also been a LOT of questions, and we’ve collected official (and unofficial) answers to all of them.

The Basics of the Dexcom G5 Mobile CGM System

1. What’s the main difference between the Dexcom G5 and the “G4 with Share”?

The “G4 with Share” was the first system to allow sugars to be displayed on an iPhone or Apple Watch, but this required the receiver to be nearby. (Here, the iPhone is acting like another display to the receiver).


The G5’s key difference is that the user no longer has to carry around their receiver, because the iPhone can function alone as a receiver.

Keep in mind that both the G5 and G4 uses the exact same G4 sensor, but they have a different transmitter. (Confused yet? Hope this picture helps)

Dexcom G4 Sensor and Transmitter

2. What are the subtle, more technical differences between the Dexcom G5 and “G4 with Share”?

As described above, the only difference is a new transmitter that comes with the G5. (Confusingly, the G5 System ships with G4 sensors and a “G4 with Share” receiver.)  This new G5 transmitter is just a tad thicker and transmits sugar readings via bluetooth to multiple devices (such as an iPhone and “G4 receiver with Share”). It also has a shorter lifespan (estimated at 3 months). The older G4 transmitter transmits via radio frequency to one device (must be a G4 receiver or “G4 receiver with Share”). The G4 transmitter is estimated to last 6 months.

2. If the G5 CGM doesn’t need the Receiver, then why does it still come with a “G4 Receiver with Share”?

The FDA insisted that Dexcom include the “G4 Receiver with Share,” and it’s always a good idea to have an emergency backup system that is medical-grade, solely devoted to diabetes monitoring (as opposed to sharing the stage with selfies, Instagram, and Angry Birds).

Pricing, Availability, and Eligibility of the Dexcom G5

1. When was the G5 released?

It started shipping September 2015

2. Will my insurance cover Dexcom G5?

It’s complicated (when is health insurance coverage not?). Many private insurances will cover CGM for Type 1 diabetes. Some insurance companies will cover CGM for Type 2 diabetes. Dexcom has an official support page to help you find out whether your specific insurance will cover CGM.

In January 2017, the FDA changed their indications for the Dexcom G5, which allowed it to be qualified as durable medical equipment. Therefore, the Dexcom G5 will be the only CGM to be covered for Medicare patients who meet the medical necessity requirements, and the exact details for this are being fleshed out. Follow this link for the latest information on Medicare and G5.

3. Do I need a prescription for CGM?

Yes, from a health care provider.

4. Is the G5 approved for use in children/pediatrics?

Yes, for children aged 2 and older.


5. I already have a G4. Can I upgrade to the G5 for a reduced price?

All upgrade offers expired at the end of 2015 (3 months after release).

6. If the G5 transmitter lasts 3 months as opposed to the G4 transmitter’s 6 month lifespan, will I be spending twice as much money on transmitters?

The official line: “Due to different reimbursement scenarios, it is difficult to estimate the cost to a patient but we made significant efforts to maintain the same annual cost to patients.”

Does the G5 Work With My [Insert Device Here]?

1. Will the Dexcom G5 work with my iPhone?

Yes, as long as the iPhone was purchased 2012 or later. All iPhones dating to as far back as the iPhone 4S are compatible with Dexcom G5. You will need to be running iOS 8.1.2 or later. Dexcom has a full table of compatibility.


2. Will the Dexcom G5 work with my iPod Touch or iPad?

Yes, as long as they were purchased after October 2012. This includes all iPad Air’s, all iPad Mini’s, and the original iPad 3rd/4th generation. The iPod Touch 5th and 6th generation models are supported. You will need to be running iOS 8.1.2 or later. Dexcom has a full table of compatibility.

3. Will the Dexcom G5 work with my Android or Samsung Galaxy phone?

Not yet (in the US), but Android compatibility was unveiled in Europe on January 2017, so it should be enabled in the USA any day now!

While many Android phones can be used to FOLLOW blood sugars using the Dexcom Follow app, one of the previously discussed Apple products must be used to actually SHARE blood sugars. Check out Dexcom’s compatibility matrix to see if your Android device is able to FOLLOW someone’s blood sugars.

4. Why doesn’t Dexcom fully support Android? Does Dexcom hate Google?

The answers are complex. Dexcom doesn’t hate Android or have an anti-Android bias. In fact, Dexcom recently partnered with Google  to develop future products, so put the tinfoil hats away.

Android compatibility was unveiled in Europe in January 2017, so USA support should be on its way.

5. So when will the Dexcom G5 Mobile App support Android?

Android compatibility was unveiled in Europe in January 2017, so USA support should be on its way.

6. So with G5, can the iPhone do everything that the receiver does? Can it do more?

Pretty much! You can log events, calibrate your blood sugars, change your alarm thresholds, stop/restart sensors, all from your phone.


Even better, you can actually adjust the alert tones for each specific alert! (No, they didn’t offer “Get Low” by Flo Rida or “She’s So High” by Tal Bachman as an option).

7. Will the Dexcom G5 work with my Apple Watch?

Yes, with a software update that was released on March 14, 2016.

8. Will the Dexcom G5 work with my Animas Vibe Insulin Pump?

No. The Animas Vibe communicates with Dexcom via the “G4 with Share”‘s radio signal, and the G5 system utilizes bluetooth. Therefore, not even a software update will fix this issue.

9. Will the Dexcom G5 work with my Tandem T:Slim G4 Insulin Pump?

No. The Tandem T:Slim G4 communicates with Dexcom via the “G4 with Share”‘s radio signal, and the G5 system utilizes bluetooth. Therefore, not even a software update will fix this issue.

Apple iPhone Questions

1. Can the Dexcom G5 synchronize with Apple Health (aka HealthKit)?

Yes, but this option is NOT enabled by default.  To turn it on, open the Dexcom G5 Mobile app, click on the menu icon -> Settings -> Health -> then tap “Enable”.


Also, when enabled, this feature operates on a 3 hour delay, meaning that Apple Health will only have access to sugars that are at least 3 hours old.

2. Can I view my Dexcom G5 CGM data in other iPhone Apps?

Yes, via HealthKit (see #1). However, keep in mind that Apple Health (and other apps) will only have access to sugars that are at least 3 hours old. The other apps must be HealthKit compatible.

Apple Watch Questions

1. Is the Dexcom G5 compatible with my Apple Watch?


2. Great! So can I leave my iPhone at home and track my own sugars just using my Apple Watch?

Sadly, no. This could possibly change with software updates on Dexcom’s and Apple’s end, but I don’t anticipate leaving the iPhone at home until at least late 2016.

3. Ok, but can I follow someone else’s blood sugar using just my Apple Watch (apart from my iPhone)? 

While the new software update for Apple Watch does allow some apps to run natively and pull data from the Cloud using WiFi where available, the Dexcom Follow app for Apple Watch has NOT been updated to incorporate this feature. Therefore, you’ll need an iPhone nearby to follow anyone’s blood sugar on your wrist.

4. Can I view my CGM data directly on my Apple Watch clock face? 

Yes, Dexcom finally enabled this feature in January 2017 for the G5 Mobile App. Make sure your iPhone has the latest version of the Dexcom G5 Mobile App to enable this feature.

Before January 2017, there were two workarounds to do this. The first option (pictured left) is to use an app developed by a person with Type 1 called watchSugar. (Read our watchSugar tutorial). The other option (pictured right) is to change the settings on your Apple Watch to have the Apple Watch display the Dexcom G5 app first (instead of a clockface). Since you can see the time in the top right of the screen, you can view both the time and CGM data at first glance.


5. Will I get alerts on my Apple Watch?


Yes! The Apple Watch will mirror notifications from the phone. Therefore, it will show “Low Glucose Alert” or “High Glucose Alert,” etc.

6. Is there any difference between the Apple Watch Series 1 and Series 2 when it comes to the Dexcom?

Not really. While the Apple Watch Series 2 offers a brighter screen, better waterproofing, longer battery life, and faster computing power, the Apple Watch Series 2 does not introduce any new features for Dexcom users. (The Apple Watch Series 2 also includes GPS, but this does not affect Dexcom users either).

Connectivity Questions

1. What happens if my phone loses data connection?

Good news! The Dexcom G5 CGM app only requires an active bluetooth connection to view sugar data on the phone. That means you don’t need an active cellular service or Wifi. So even if you work in a nuclear bunker, your iPhone and Apple Watch will be able to display your own CGM data as long as it is connected to your sensor via Bluetooth.

Keep in mind that other people won’t be able to FOLLOW your blood sugars. This means that only the nearby iPhone can display blood sugars without a data connection.

2. That’s great! Does that mean I can view my blood sugars while in airplane mode?

Yes, but you MUST re-activate bluetooth after turning on airplane mode. So, when you fly, activate airplane mode, then turn just your bluetooth back on.

airplane-g65Keep in mind that other people won’t be able to FOLLOW your blood sugars. This means that only the nearby iPhone and Apple Watch can display blood sugars without a live internet connection.

3. What happens if my sensor/transmitter strays too far from the iPhone?

It operates similarly to the non-smartphone receivers. The iPhone will display a “Signal Loss” error, and glucose readings during that time of separation will not be recorded or shared. Once the sensor/transmitter comes back in range, the sugars will be recorded again. Keep in mind that the gap in data won’t “backfill,” meaning that those sugars are not recovered.

Miscellaneous Questions

1. Are the rumors true that the Dexcom G5 transmitter has a hard stop date and will stop working at a set date?

Yes, a low battery message is displayed at a predetermined date, 2 weeks before the official stop date (somewhere around day 111).

2. How come you didn’t answer my question?

Ask your questions in the comments below, and I’ll give you my best answer!