Dexcom G6 - How much of an improvement over G5?

A bit of history here:

When the G5 first came out, I took advantage of Dexcom’s “we’ll give you a free upgrade kit” offer. Fortunately I did NOT update my receiver and chose to evaluate the system with just an iPod Touch.

The system, compared to the G4, was absolutely horrendous:

  1. Frequent missed readings, even at a range of 3 feet. The G4 worked with the receiver almost anywhere in my apartment.
  2. No capability to backfill missed readings from the transmitter, which made issue 1 far bigger than it should have been. Compare to xDrip+ combined with a Share receiver - while the receiver couldn’t backfill from the transmitter, it almost needed to, but the mobile app could at least backfill from the Share unit. (In numerous cases at my old job, I was allowed to have the receiver with me but NOT a phone for security reasons - the receiver was only allowed due to medical device/safety of life exemptions from DoD policy.)
  3. At that point, all indications the xDrip team had seen was that the G5 transmitter didn’t support raw BG numbers and/or “noise” status. While it’s never been a part of official Dexcom implementations, I consider it absolutely critical as it lets you know when the sensor is flaking out. The G5, on the other hand, would treate the sudden reversal of trend from correcting a low with carbs as “noise” - so it would indicate a dropping BG level when it changed filter strength with no indication that it had done so. Yeah yeah I know we’re supposed to confirm with a fingerstick before any treatment, but if I’m 70 and the CGM just said I dropped by 10 - I’m gulping sugar ASAP. I have no idea how in the world Dexcom got approval for non-fingerstick treatment decisions given that the G5 gave absolutely no feedback as to filter algorithm status.

As a result, I went back to G4 transmitters + Share receiver + xDrip+ and never once had any regrets of doing so. The G5 system was across-the-board inferior to the G4.

I’m at the point where I need to re-order supplies, and I’m considering moving to the G6 (because being able to take Tylenol again would be nice…) - Has Dexcom fixed the severe flaws that made the G5 nearly unusable?


I would suggest to stick with what works for you.

If you like the G4 then keep using it.

The ability to not be thrown off by acetaminophen is a pretty big positive…

The big question then becomes, did Dexcom fix the G4->G5 regressions when they released the G6? Some of the xDrip+ documentation kinda hints at this, but it’s not entirely clear.

Obviously significantly loaded question full of implications and assumptions.

I would suggest if the G4 works for you then you should stick with the G4.

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So you yourself have stuck with the G4? What is your personal experience?

“implications and assumptions” - How is my personal experience with the G5 for two months an “assumption”? So far you have provided nothing of use, you have not described anything regarding your personal experience with G4, G5, or G6.

Part of the problem is that I’ve read that Dexcom appears to be forcing G5 users to migrate to the G6, which strongly hints that the G4 sensors/transmitters may be getting EOLed too. I’m absolutely shocked that Dexcom was willing to continue shipping G4 product after I’d tried the G5, although it was always a major PITA because you could only order G4 product from them by phone, online/web-based orders were G5 only. (Or at least were for me after my account had been “tainted” with association with the G5…)

And again - acetaminophen compatibility is a major benefit. Being able to take Excedrin for headaches has been a contributing factor to me going without CGM for extended periods of time. So in this regard, the G4 is not “working for me” in its entirety. It’s vastly superior to the G5, but in addition to making the G6 not get thrown off by acetaminophen, did Dexcom fix anything else with the system during the transition?

I have used G4 for many years, after upgrade from Dexcom Seven. Last month, I did a comparison with G6, wearing both at same time. The G6 inserter device is definitely a big improvement.

Accuracy wise, they were about the same for me, G6 sometimes picked up the rise or fall sooner. I also installed xDrip and used with both G4 and G6 (on different devices).

At this point I’m staying with G4, due to it being lower cost (more extended days of use for sensors and transmitters). I have not used G5.


Thanks, that’s useful!

What were your experiences as far as missed readings - does the G6 backfill? (I see some indications that Dexcom may even have fixed this in later G5 transmitters with a firmware update?) How was the range of the G6?

It sounds like your main reason for going back was cost - I have fairly decent insurance coverage for CGM supplies so the G6 probably wouldn’t cost me much more.

Also one of the other threads here implies pretty strongly that one of the biggest benefits of the G4 (sensor longevity in real-world use) disappeared in newer manufacturing batches - which is also my experience with my most recent batch of sensors.

Not everyone’s experience is the same, but for us the G6 is a big improvement over the G5. Yes, it backfills, but for us it is more sensitive to changes and is faster to react. It also works with our Tandem pump and that is a big plus as well. No drawbacks for us at all, however not everyone has been as happy. Can you get one to try it?


I’m definitely considering talking to my endo to figure out a plan and what options are available for an evaluation. (He’ll probably immediately kick me over to his diabetes educator, she handles the equipment references, and for the most part I only need the endo’s involvement for the purposes of navigating the joys of insurance approvals…) I could probably evaluate just with xDrip+, after all that would be my primary use case, which means not having to invest in a receiver.

Did you have experience with G4 at all? What was your experience as far as range from transmitter with the G6? DId you notice any differences in reliability between client devices (receiver vs. iOS vs. Android)?

No, my son was only diagnosed 3.5 years ago, so we started on the G5 and just dealt with the dropout issues. Our primary receiver is the pump, the secondary receiver is the phone. The pump and the G6 are really great together, since it uses the data for some treatment decisions Tandem and Dexcom worked together to improve the connectivity. On my son’s pump we have almost no dropout. On the phone there is some, but much less than the G5.


OK, it sounds like Dexcom has made a LOT of software/firmware improvements since the G5 first came out, including what sounds like definite improvements from G5->G6 for the specific issues I had.

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I never used the G4, but I used the G5 for 2+ years.

I think the G6 system is more accurate. The inserter is huge (no pain in the insertion though, just a bulky plastic device) and occasionally I’ll get a sensor that bleeds and must be immediately replaced. Otherwise I have no complaints.

I had few complaints with the G5 though. I don’t use xDrip+. I think my Bluetooth connection is either the same or better with the G6. I also don’t have a frequent need for backfill, so I’m not even really sure if that changed between the G5 and G6. You could probably ask a Dexcom rep about that last one though.

Sorry I can’t be more helpful. I guess my expectations are just different. I’m definitely not interested in going back to the G5- if that opinion helps at all?

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Hmm… I’ve occasionally had “bleeders” with the G4, often those actually wind up being the best-performing sensors after giving them 1-2 days to settle down. (They’ll be horribly flaky at night for the first two nights). Those were the sensors that would still be rock solid even at 2 weeks. (While some people have been able to do restarts to go well beyond 2 weeks, I’m personally paranoid about infection if going that long.)

The only time I’ve had issues with sensors failing very early was, as I think I mentioned earlier in this thread (maybe in a reply to another thread recently) that I would often have failures when inserting into a region that I discovered had lipohypotrophy after I had lost 15 pounds.

I never had a bleeder with the G5. Upon insertion, all sensors showed a value.

By bleeder, I mean a site that bled so much that after the 2 hour sensor warm-up, the value shows as “very low” for at least an hour (which is when I decided the site wasn’t worth the effort). That has happened on 3 occasions. I’ve been using the G6 since December.

OK, I never had a sensor THAT noisy on insertion. Usually if I had a “started flaky then became very solid” sensor, it would be flaky during the night… Or it would often get a bit glitchy if I were merely lying down on the couch. In any such case I’d see signs of bleeding from the insertion site.

I think root cause of the problems with the G5 and by extension the G6 is the way the receiver phone handles Bluetooth. Some phones are very good with bluetooth and some just don’t work. I use xdrip+ but the same problem bluetooth problems exist as for the Dexcom App.

I have used both the G4 and the G5. I loved the long range of the G4 (I could wander around the house without my receiver and it still worked), but I wanted to get the CGM data on my phone so I could customize my alarms, dump my data to visualization software (Tidepool) directly, and use other software like AndroidAPS, so I first got a converter (G4 to Bluetooth box) and then went to the G5.

My phone would only get about a 90% capture rate with the G5, so I switched to using a Sony SW3 smartwatch for data collection and got a 100% capture rate - as long as my watch is about 10 feet from my sensor. At some point, the xdrip Bluetooth collector software was updated and now I get ~100% capture rate on my watch or phone.

I am going to be playing with a new (to me) Android phone and maybe the Dexcom App later this week with another G5, so I will see if the frustration is still there with the Dexcom App. But again, it is very phone specific.


I was a longtime G4/G4 with Share and before that a SevenGo user. I skipped the G5 and switched from G4 share to G6 (both using Xdrip+, since the Dexcom software is horrible) and have pretty much found the G6 to be better in almost every way. More accurate, sensors last longer, smaller/flatter transmitter, better inserter, no downtime between sensor restarts (with appropriate Xdrip+ setting), no receiver needed, etc. The only minor difference is that the G4 receiver had a more stable bluetooth connection with the transmitter than my phone does, which occasionally needs to be restarted to restore my connection. But my phone does this with my bluetooth headphones too, so it might not be a Dexcom issue. But the phone can backfill missed readings from the transmitter, so this is a minor issue. Not being able to use a phone due to DoD restrictions might be a big problem for your though. The new G6 receiver is huge, horrible, and will not work with Xdrip+. This is a plus for me, since I just left the damn thing in the box and run the G6 off my phone and carry one less thing around, but I would be SOL if I couldn’t use my phone.
I know a lot of people have had issues with the G6, and I’ve had a few as well, but it’s leaps and bounds better than the G4 in so many ways for me.


I had the G4 since it first came out in the UK, then the G5 and now I’ve just started on the G6; every generation was a notable improvement for me, with the G6 starting brilliantly, absolutely spot on readings from insertion and picks up every trend with no real lag. Really early days, but if it carries on like this, the G6 will be way ahead of the previous generations in every way…