Dexcom G5 CGM, iPhone, and Apple Watch: Your Questions Answered

Dexcom's G5 CGM Syncs to iPhone
[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.

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)


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).

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.”

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.

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.

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).

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.

Keep 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.

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!

  1. Hi,
    Re the Apple Watch setup/workaround for the G5, what is the delay/lag between the value shown on the phone and the one on the watch, if any?

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    Hi BokiXI, when “following yourself”, if using the Dexcom Follow workaround, it depends on how you are viewing the data. If you are using the glance view, the data displayed at first might be up to 10 minutes old, but will quickly refresh on demand. If you are using the new watchsugar app to view your dexcom info on the watchface as a complication, it can be as old as 17 minutes. (you can read about about watchsugar here:

  3. My son has the Dexcom G5 that was upgraded from the G4. It worked well for 6 months until the buttons on the receiver failed. After they sent him a replacement, he started having problems with the receiver and his IPhone not providing audible alerts when his blood sugars go below the low glucose level and the urgent low level. Dexcom has changed out the receiver multiple times, and on occasion it will work for 3 days. Subsequently, we get back to the situation where there are no alerts on the receiver nor IPhone. He is a very brittle diabetic and this is causing us grave concern–so much so we arranged to meet with technical support management at Dexcom in San Diego. They are earnestly working on a “fix”. Have you heard of this problem and if so might there be a solution?

    • Avatar

      Hi Gary. Thanks for the comment. The issue with audible alerts is fairly well-documented and Dexcom has initiated a voluntary recall if there are any issues: FDA Link. The perplexing part is that you continue to have issues despite the typical solution of exchanging the receiver, and so I think Dexcom is doing the right thing by trying to meet with you and troubleshoot. Let us know how it goes!

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    Thank you David. We will keep you updated.

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    After working extensively with Dexcom and Apple, Dexcom suggested we wipe the phone clean and reload the most recent IOS (9.3.2) and reload the Dexcom App. If that didn’t resolve the problem, they wanted us to have the phone replaced. It should be noted that during the period of time we couldn’t get either the I-Phone or the Dexcom receiver to provide audible alerts, we purchased an Apple Watch. This was the only device that was working. Despite the Apple diagnostics showing no errors, Apple graciously replaced the I-Phone 6. Again we were not receiving audible alerts on the I-Phone which was running 9.3.2 and after downloading the Dexcom app. Since the Apple watch was receiving alerts, we decided to explore setting on the I-Phone for the Apple watch. Apparently the watch does not have the same ring tones as the phone. It became necessary for us to disable the “mirror I-Phone alerts” option of the phone to the watch for the Dexcom App. When we did this, the audible alerts started working on the phone. This approach also enabled the receiver to start working. Bottom line–it seems like there may have been something wrong with the original I-Phone though it passed diagnostics and was less than 1 year old. Dexcom is further investigating these settings.

  6. Avatar

    im not sure how to set up the G5 share and every time I do…it doesn’t work. what do I do? I really need help

    • Avatar

      To best help you, answer these first few questions:
      1) what exactly are you trying to do? View your G5 tracing on your phone?
      2) What CGM and smartphone do you have?
      3) What is working so far? Are you able to view your CGM tracing on your dexcom receiver?

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    I am constantly getting a message on the watch face of the Apple Watch that says ” check G5 mobile app on your phone”. How do I get rid of this! What am I supposed to be checking? Everything seems to be working fine. It is just bothersome and takes an extra step to reach the info I need.

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    David, I have an iPhone 5s with a Watch OS2 and the new Dexcom G5. These are my 1st Apple products so I am a real newbie with them. I had no problem setting up the G5 as a receiver on my iPhone but I can NOT get the watch set up to show the G5 info from my phone. In your post you mention 2 ways to do this but only have a tutorial on using the watchSugar. How do I set up the G5 Follow? thanks!

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    Am I understanding you correctly if I say that the iPhone will communicate with the sensor fine via bluetooth even if there is no internet or data connection? Is this true too for the receiver?

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    I’d like to get an apple watch but there is a series and a series 2 available now.
    I have the G5. Is there a difference between the two series apple watches as far as support goes for the descom?

    • Avatar

      Great question! Functionally, the Apple Watch Series 2 should be nearly equivalent to the original Apple Watch. (The newer model might run a little faster and/or have better battery life, but it doesn’t have different functionality).

  11. Is there any way to turn off the urgent low sounds?? They keep alerting me after I have corrected and it is very frustrating. I was hoping the Apple watch would keep me from having this problem.

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    Hi David – by any chance, do you know how to keep the view of the graph on the watch as a 3 hour view? I know I can turn the side knob and see the 3 hour view, but I cannot get it to stay that way once the watch goes to sleep and turns back on.

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    G5 is working great on my iphone but my apple watch is reporting “check G5 mobile app on your iPhone” what does that mean and how can I resolve? It was previously working fine on the watch previously.

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      Did you find a solution to this? Mine is now doing the same!

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        I upgraded to a newer model iPhone and restored to it from backup, and now the iPhone app shows this as well. I’ve tried restarting both, removing from the watch via the watch phone app, etc., and nothing works.

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    Hi David,

    I’ve been using the Dexcom CGM for a little over six months, I find that the phone disconnects from the transmitter quite frequently. In the middle of the night even right next to my transmitter. Any thoughts on how to keep the connection alive? It looks like the phone might be killing the app when it’s not actively up on the screen. Any help would be appreciated! Thanks!


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    Would it not be enough to have the G5 CGM sensor with an iPhone. Is there anything forcing a 1100 $ purchase for the entire kit rather than a 300 $ sensor/transmitter ?

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    Is it possible for the Apple watch to vibrate and have a sound alarm for a low glucose notification?

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    I have a G5 CGM and 2nd gen apple watch and iphone6. I have the watchsugar app on the phone and watch but can’t get it to work on my watch. It’s stating no signal. The dexcom app does relay the correction information on BG. What do I do to make this watchsugar app work so I can see it on the complications on the watch face? Thanks!

  18. Avatar

    David, thanks for the great info here. Two things. 1) Your “strayed too far from the phone” error message above isn’t the right one. In that case it would show a single question mark and a bubble that says “signal loss.” The three question mark version is different — it means there’s some kind of problem with your sensor, which can happen if you take Tylenol or the sensor isn’t working properly. The two error messages are different. Second is a question that I can’t find the answer to anywhere. My doctor’s office likes to take my receiver when I show up for an appointment and download data that way for the doctor to review before she sees me. They don’t like working with the codes the Clarity app provides. But I don’t regularly carry my receiver around with me. Do you know if the receiver will carry the full blood sugar history, even if the data wasn’t received by the receiver itself (and instead was received by my iPhone)? My doctor’s office thinks it does, but the last set of charts she was looking at looked strange to me — like it was based on very incomplete data. I’ve tried emailing Dexcom this question and I don’t really get helpful responses…. Thanks again!

  19. Avatar

    Hey David, I just got the Apple Watch for my G5 but it’s driving me crazy that I can’t “dismiss” high (or low) alerts on the watch. My phone is set to just vibrating when I’m high so that if I’m in a meeting, it doesn’t sound more than a vibrate. While wearing the watch, if I get a high alert, I can click “dismiss” but it doesn’t actually dismiss it and keeps going off (with a chime) until I open it on my phone. Any ideas? Thank you!

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    How do you log out of dexcom account in G5?

  21. Any updates on using the Apple Watch without having the iPhone nearby?

    • Avatar

      As of this post, I have not heard any progress towards allowing the Apple Watch to work without an iPhone nearby.

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    Have you herd of health insurance reimbursing you for an iPhone and iPhone watch if you have a Dexcom 5

    • Avatar

      Sadly, I have not heard of this. That’d be amazing!

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    I’ve noticed that when using both the iPhone and the receiver, if the phone encounters signal loss (which can happen to me even when the phone is next to me on the nightstand), when it finally receives a signal from the transmitter, the graph for the previous three hours suddenly fills in. This doesn’t happen if the receiver isn’t active. Does the receiver send this data to the iPhone? If so, how? There is no listing for the Dexcom receiver in Bluetooth devices on the phone, just the transmitter.

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      That’s an interesting observation. I don’t have an explanation for why that is happening.

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    I keep getting a error message about every half hour or so telling me to exit and restart the dexcom app on my iPhone. Saying there was a temporary error. What is this and how can I fix it?

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    The sideways iPhone display for the G5 data always goes to the 12 hour time span. Is there any way to have it default to a different timespan, say 1 hour?

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    I´m from germany and i use the G5 with the Dexcom “US” App on my Iphone 6s because of the conectivity to the Watch_IOS2. The system works, but sharing status is “X”. The cloud symbol is green and the phone remains amber. Further on, my followers don´t receive an invition mail. Tried several times, but it doesn´t work. Also spam folders checked. The phone has an active internet access. I followed the inapp troubleshooting guide, but it still doesn´t work.

    Do you have an idea?

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    Hi there! Will this app send me a reminder before my sensor expires? Thanx.

  28. How does the glucose electrode get inserted? Especially cost effective since diabetics usually can’t get insurance. Funny I worked on glucose electrodes under Dr Gordon Fricke in 1974 I think.

    Lynn McCarty

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    I am used to one button access to blood sugars with the G5 receiver. This is useful during running and biking. With my I-phone I must push the button to open the screen, put in the security code and then open the Dexcom app. Is there a way to expedite that?

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    When your initiating the dexcom g5 you are to plug in two sugar readings. After you put that in your smartphone what should take place. His phone continues to stay on that page regarding the sugars.

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    Does DexCom pull from my data on my I Phone? And if yes, typically to what degree?

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      Other than your CGM (glucose) data, the Dexcom app only pulls data that you manually enter within your Dexcom app (carbs eaten, units of insulin given). It does not pull other data from your iPhone.

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    Apple has just released that they are going to offer an Apple watch 3 that they advertise you are able to leave your phone at home but still use all of the features of the watch. Will the Apple Watch 3 be able to read directly from my CGM transmitter (like the iPhone app already does) so I can leave my phone at home and still get CGM readings and updates on my watch??

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    Dr. Ahn, Thank you for your post regarding the ridiculous Medicare restrictions that aggressively do not allow the use of a mobile phone or other such device to assist diabetics with monitoring their blood glucose levels for all the reasons you mention and more. I would like to know if there are any groups opposing the ridiculous Medicare restrictions. Through my sister, I have been in touch with Dr. Tom Price (before he was fired); my sister worked with him when he was a representative from Georgia. We continue to be in touch with one of the key contacts from that office. In addition, I have contacted my Congressman and am in the process of sending in the forms he sent my wife to fill out along with a lengthy explanation of the situation. My guess is that it will do no good but I am trying. It is a shame that Medicare puts my wife’s health at greater risk because of super enforcement of some stupid restrictions. I have found no one who supports the restrictions from you, to my wife’s diabetologist, to anyone at Dexcom. We are not asking Medicare to pay for the phones, only allow their use to improve the care of Type 1 diabetics like my wife.

  34. Avatar

    My iPhone consistently loses signal to my g5 transmitter, even with my phone in my pocket or sitting right next to me. Very frustrating. Just had a loss of signal while typing this message! Any ideas why? It happens randomly but consistently.

    • Avatar

      This has happened to me too. There my be competition with other Bluetooth devices you use with your iPhone so make sure you turn off as many as you can. But since I’m not an IT guy, the folks at Dexcom customer service can hopefully help.

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    My iPhone consistently loses signal to my g5 transmitter, even with my phone in my pocket or sitting right next to me. Very frustrating. Just had a loss of signal while typing this message! Any ideas why? It happens randomly but consistently.

    • Avatar

      This has happened to me too. There my be competition with other Bluetooth devices you use with your iPhone so make sure you turn off as many as you can. But since I’m not an IT guy, the folks at Dexcom customer service can hopefully help.

  36. Avatar

    Dexcom G5 with iPhone 6
    New to cgm with iPhone monitoring. Bluetooth signal to iPhone not good range at all. Will lose notifications but when check the dexcom supplied receiver which is farther away I get readings. Anyone else had this issue? To the point of not using app on iPhone but would rather if it would work.

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    My apple watch is now telling me to “check G5 mobile app on my phone. I am not sure why?

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    I have a question do you have to have internet connection on your phone? I have Bluetooth on my Samsung J3 327 A

    • Avatar

      Hi Ruth,
      Your phone does not need an internet connection to display CGM data from a Dexcom that is physically nearby and paired using Bluetooth.

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