Looking for G4 to G6 users

…because I’m about ready to throw my G4 out the window!

I’ve been hesitant about upgrading to the G6 solely because the G4 wasn’t super accurate for me, and I thought it was just how it reacted to my body. But when I ordered more sensors the other day, the {slick} customer service rep talked me into upgrading to the G6 in another month when my transmitter warranty runs out. He said the G6 runs on a different algorithm than G4 and that’s what helps it be more accurate. Ok, fine, I can see that. It’s newer technology after all. But it’s still going on MY body…

Today of course, I attempted a new thing for my breakfast bolus. This 3-day old sensor was about 40 pts off when I checked first thing after I woke up (138 vs the 98 via my omnipod), I told Dex I was 98, it corrected itself to 118, cool. Ok.
No alarms all morning. Great! Super busy at work filling in for a coworker who’s on vacation…didn’t get an alarm so didn’t bother to, ya know, ACTUAL CHECK THE DEXCOM SCREEN. My bad.
Checked it just now - it’s requesting a calibration with a blood drop and current reading is — for the past FOUR HOURS. Shouldn’t that have alarmed, you know, 30 minutes in?? Turns out I’m 184, and God only knows if I’m trending up or down. I’d turn this stupid thing off and stick it in a drawer for a month if I wasn’t pregnant.

Oh, and then my favorite thing - after I calibrate it, after I TELL IT that I’m high…it buzzes and tells me I’m high. Does that not get on anyone else’s absolute LAST nerve??

Can anyone who upgraded directly from G4 to G6 please please please tell me my experience with the G6 will be better??
My baby is due Sept 11th, so I’d hate to be messing around with a wacked out CGM system while dealing with sleep deprivation and learning to breastfeed and all other kinds of new parent things!


1 Like

Still on the G4 myself. When the receiver is 40pts or more off, it triggers that recalibration routine. Been thru that a few times with “iffy” sensors – though, my experience has been good overall with the G4. I am uncertain when Il’l make the change to G6, as I’m quite happy with the collection of technology I’m using currently.

My daughter currently has the 5 and we can’t wait to upgrade to the 6 in August. I read this review and I think we will like it better than the G5.

Never had the G4 as we are new to T1D. The G5 can be off a lot as well (as much as 50 points) and we are still doing finger pricks more than we should but gotta be safe with a kid.


Nice article! Thanks for that link.

I used the G5 a couple of years ago, took a break from CGM, and started with the G6 about 2 weeks ago. I was a bit hesitant as I has been using the freestyle Libre since April, and that piece of junk was always inaccurate. Out of 11 sensors, 2 were accurate and 9 ranged from 30-200 points off at all times. As you can imagine, I was a bit hesitant in switching to the G6, but was told great things by my doctor.

15 days in, and I am super happy. I test my blood once every few days, and it is generally within 0-5 points of the G6. One time it was a 9 point difference. I found the G5 to range from 0-20 points twice a day, back when I was on it.

I have found the G6 to be much more accurate than the G5 and the Libre. Hope that helps.


I’ve used the G4 and upgraded to G5. Both have been very accurate, often times having the same reading. With both the G4 and G5 I’ve been able to use the sensors well-beyond the 7-day life, with great accuracy. I’m not sure if/when I’ll upgrade to the G6 because testing to calibrate doesn’t bother me. That and although there is a work-around to extend the life of sensors, beyond the 10-day period, I don’t know if it will work for me.

I hope things even out for you soon. Could it just be the pregnancy hormones at work as to why the sensors are wacky? How long have you been using the G4? Has it always been wacky for you, or just since the pregnancy?

Eh, I’ve noticed the quality of the G4 sensors going downhill for a little bit now. I used to be able to get a solid 2 weeks out of them but now I don’t even bother and just change them after a week.
Honestly, the pregnancy hormones could have something to do with it, but my a1c has been in the low to mid 5’s the entire time. The pregnancy also corresponded to a new order of sensors after the G6 was starting to be released. But of course there’s no proof of what I suspect there…

I’m still on the G4. Could you just return to the G4 until after delivery?

1 Like

I could. It may end up happening that way, since there’s no telling what exact day I’ll get my G6 and when exactly I’ll go into labor (hoping he’s early). I just…want to believe the G6 will work more accurately for me during labor (endo has already given instructions for me & hubs to manage all of that ourselves) but experience with the G4 has me doubting big time.

A nurse told me the other week that her G6 was considered more accurate than a traditional manual BG machine. I couldn’t believe it. New gold standard.

The sensor is not measuring same glucose level as BG. Need to keep in mind the lag between BG and SG, especially when BG is rising or falling.

When I see a difference between dexcom sensor (SG) and BG check, I always pause to consider food on board and what I might expect BG to be 20 minutes later. Exercise can also impact expectations of valid differences between the numbers.

1 Like

Isn’t part of the algorithm’s job to adjust the number it puts out on the screen based on what bg should be? Not just what its measuring as?

I’ve been using a gifted G4 for past 4 years (live in Canada where it’s difficult to get insurance for this awesome piece of technology). I’ve not had any of the problems you’ve had. I only have good things to say for the G4/G5 sensors … that last me on average 4 weeks and the sensors are expired to boot. I’m going to be next learning how to replace the G4 / G5 battery in the transmitter for those Canadians like myself who are self funded … there is a great group on Facebook for Americans where they replace the battery for G4/G5 for a great cost … but due to shipping outside of your country and in US dollars … it’s hard for some Canadians to fork out the monies. So I’m attempting with the help of Amber and her hubby John who do this great work for Americans … to have a similar set up for Canadians (I already distribute expired sensors from American T1D mates when I attend diabetic conferences … but due to political circumstances right now between our two countries … many Canadians are avoiding stepping into the USA … waaaahhh … miss the great selections of diet drinks we can get in your country … but water is good … yeah … water is good :wink: )

Okay, as usual, my fingers flapped like my lips do when I get excited about advocating. Good luck @kccosmo with having the best outcome for your little bun in the oven!!!

1 Like

Well i was trying not to say that I think the older sensors work much better, so that might be where your luck is coming from!

When you eat, glucose can directly raise BG as food is digested. From the blood stream, the BG gradually is distributed throughout the body, (tissue where sensor is) causing a lag. I know this is how it works for me with G4. If I eat higher carb, and test BG before and immediately after I eat, I see a big rise in meter BG. Then I have observed how long it takes to see Dexcom rise. It may vary by person due to many other factors, such as impaired digestion, activity level, food content, hydration, age of sensor, etc.

1 Like

Ok KCCO, I fit the criteria that you’re looking for. I used the G4 for at least 6 years and just switched to G6 in June. I have some very strong opinions, both good and bad.

First, the good:

  1. No fingerstick calibration is FANTASTIC. This is an outsized advantage.
  2. New inserter is far easier to use than the old one.
  3. 10 day wear vs 7, though i often used mine for longer.
  4. Accuracy has been mostly good. When you feel differently than what the G6 shows, do a fingerstick. You can do calibrations, though it is not recommended.

And now, the bad:

  1. Sometimes the factory calibration out of the box is very wrong, and when you try to correct it, it refuses your calibration. Usually this happens with a new sensor, and eventually it synchronizes. But if your fingerstick is too far from the factory calibration, it will not listen to you.
  2. New inserter cannot be reused and is extremely wasteful, with no recycling plan in place
  3. You cannot continue to use your sensor beyond 10 days, because of the factory calibration.
  4. This is a huge one…if you’re coming from G4, your transmitter uses RF (radio signal) to transmit data. The G5 and G6 use Bluetooth. On surface, this seems like a great idea…you can transmit bg data to your phone! In reality, the range of your transmission to receiver is DRASTICALLY cut. The battery life (of your phone, transmitter AND receiver) are DRASTICALLY cut. You will need to buy 2 transmitters to last 6 months instead of one, because Bluetooth is a battery sucker. We have a 2 level house and I always have to make sure I’ve got my phone or receiver on me, or nearby on the same level of the house, or I risk losing the signal! Sometimes rolling onto the transmitter while sleeping causes the receiver to lose signal. With RF/G4, this was never an issue. As long as the receiver was somewhere in the house, it would continue to receive a signal. This is a HUGE downgrade, from my perspective, and I wish they would sell an RF version of the device. I have to constantly keep my phone plugged in because constant Bluetooth use drains it, and I even need to wear pajamas with pockets as I walk around the house so I don’t lose signal. They did add a 3 hour memory to the transmitter however, so unlike G4 if you lose signal, it will fill in the gaps. That seems to be Dexcom’s concession to this annoying problem). Surprisingly, the earliest medtronic cgm sensors did this from the beginning and i thought it was strange that Dexcom did not have this feature with the g4.
  5. Compounding the Bluetooth range issue is that they eliminated the belt clip, making it even harder to keep the receiver on you with easy access.
  6. The design of the receiver screen is not optimized. Although the size of the graph is similar to the G4, the vertical orientation makes it feel smaller. Plus the G6 white background with black writing is harder on the eyes than the G4’s super clear, bright colors on black. Additionally they eliminated the separate trend arrows and instead incorporated the trend arrows into a circle surrounding the number, making the trend much harder to read. Frustratingly, they did this for no apparent reason as there is plenty of unused white screen space to the left and right of the number where they could have very clearly drawn large trend arrows separate and apart from the number.

This sums up my G6 impressions. Ultimately, eliminating fingersticks will keep me going back to G6, but boy does it have some really frustrating, avoidable problems that I’d wish they would address


Great review @schleima !

I’ve used the G4 and G5.

I typically get 21+ accurate days with my (G4 or) G5 sensors; at times going 28+ accurate days, before I have to replace it.

Neither the G4 or the G5 had an inserter which could be reused, as an inserter, that I know of. Each new sensor has a new inserter. That said, one part of the inserter, I think, is able to be used to remove the transmitter from the sensor, but I’ve never used it. I just pry the clips apart and the transmitter disengages easily enough.

I’ve read there is a work around to the hard 10-day reset. It won’t work for me though, but should for a lot of people.

Thank you for mentioning the battery life of the G6. With the (G4 or) G5 I only use the receiver. I too would really miss the belt clip. I can’t imagine not having that! Such a simple thing that I’ve grown very accustom too!

THANK YOU this was really what I was looking for!

To be honest, I don’t think anything you listed is a real deal breaker for me. I sometimes lose signal on my G4 in my house too. Or last night it was on the coffeetable not 3 feet from me & I suddenly got the out of range alert. What the crap. And I don’t have a super active lifestyle (yet - we’ll see how this first child changes things!) so I’m pretty much tethered to my desk at work and the main level of our house. If I’m out shopping or something, my Dex is in my purse at my side or right in front of me in the cart. I’m sure I’ll still run into situations where I lose signal for a bit, but if that happens, I’m probably fine anyways. I’m not planning on using my phone as the receiver as of right now, so I do wonder if just an extra, constant bluetooth signal AROUND my phone will cause it to drain battery. I leave my bluetooth turned on on my phone because I use it in my car - and how will the G6 react to that?

The 10 day sensor wear seems fine too. I’ve gotten used to 7 days lately as the quality has declined on these G4 sensors. Maybe that was their master plan all along! :smiley:

The calibration thing is probably my biggest concern, since I’m having that issue now. But if it levels out and gets itself accurate within a few hours, I’m ok with that. And will Dexcom replace sensors that refuse to become anywhere near what a fingerstick says??

The extra waste/non-reusable inserter…eh, I hate it, but its not something I can devote much time to worrying about, you know?

But thank you again for all this info! It sounds like you’re happy with your decision to start on the G6 and wouldn’t go back.

This feature, alone, chased me back to the G4 when I tried the G5. Looking at that bright white screen in the middle of the night was hard on the eyes.

As someone who poked my fingers about 15x/day for years, going calibration-free has not held much appeal to me. I realize I’m in a minority on this.

Nice review!

1 Like

I am definitely hesitant to move from my G4 to G6. Even though I have an occasional early sensor failure, which Dexcom is glad to replace free of charge, I am still pretty happy with it. I don’t ever see a reason to use it with my iPhone and it has yet to work with a iWatch stand-alone. Even so I think I would still use just the separate standalone receiver as the black background, dedicated use, compact size, and long battery life are all great. I also like the old transmitter technology as they have all lasted at least a year before they need to be replaced. Also even though the G6 sensor sounds a little easier to insert the G4/G5 sensor insertion is not a big issue and they regularly last 2 weeks even though it has to be reset every week. From what I read the G6 sensor adhesive is still not good enough to hold for over a week and has to be taped just like the G4 sensor, which I do with Flexifix and keeps it secure for over 2 weeks. I do know they claim the G6 sensor does not have to be calibrated to finger stick but from the reports I hear this is not always the case and at best it might not need to be calibrated as much but to be realistic I would still check my blood glucose at least twice a day so doing the calibration is no big deal and gives me assurance that the CGM is giving me good accuracy.