Repeated Dexcom G6 failures


It was brand new on Saturday morning and was Saturday night it failed to alert us. As you don’t calibrate we just assumed it was accurate and certainly afterwards it has been accurate! It is really worrying as I just don’t trust it now.


Hi there, by way of an update we (our youngest son is T1 and 4 years old) are now back on the G5 sensor, having given up on the G6 due to repeated false readings and the 2 to 3 day lifespan. I have read all the replies to my initial post. Thank you for those. My opinion regarding the G6 being ‘rushed’ was the only way I could reason with what a complete disaster it was. If indeed it was not ‘rushed’ to release then that only serves to put even more doubt in my mind about the capabilities of Dexcom. Furthermore, we have been back with the G5 for over a week and something has changed. Perhaps in their supply chain or some such? The G5 is very inaccurate in its readings and seems even more sensitive to compression lows than we ever recall. Although the G6 took both to another level. We’ve already started researching the Freestyle Libre yet they appear to be having supply issues and are restricting supplies to current users only, as such no starter packs are being sent out. We’ve started referring to sleepless nights as ‘Dexcom Dawns’ as more often than not, the false lows and inaccurate alarms are keeping us awake, not his BG levels. Is anyone aware of a statement by Dexcom at all about swapping their suppliers or any release regarding the G6? Thank you…


Tia I am on my third one in a week, the first two failed within 3 days of having them on. Where have you been putting the sensor on at? I have been putting mine in my arm and they have bled through both times. If that’s where you’ve been putting it maybe try a different spot? I am going to try my stomach or leg for this next one. I think the bleeding is the problem with mine. If it is the spot try a different one, hope this helps a little bit.


Hi @Josh_L_Myers , thanks so much for this insight. We’ve had similar results. We switched back to the G5 and convinced Samson to try using the sensor on his belly and so far it is working better there. The data is better and it’s not failing prematurely. However, it does get itchier there and he wants to switch it out sooner because it feels uncomfortable. So it’s not a perfect fix.

Perhaps we’ll go back to the G6 at some point on the belly and see if that leads to better results.


As a counterpoint, we are on our 11th G6 sensor with no troubles. All have lasted the full 10-days, all have been placed on the back of the arm, and two have been bleeders. One which bled through the glue patch, and required a grif grip to keep it in place.


Normally 9 G6 sensors (3 boxes of 3 sensors each) in a 90-day supply order. So does this mean you are on your second 90-day order or did you get a couple replacement sensors?

If on your second 90-day G6 sensor order, it would almost certainly be a different lot and different expiration.

Assuming so, have you seen any differences so far between the first supply order and the second supply order?


We are indeed on our second order. No differences so far. We left two sensors on vacation, and had to transition to the second order a little earlier than normal.

All sensors have lasted the full 10-days, except for one sensor which crapped out a couple of hours before the 10 days was up.


To add another data point, I have been having lots of trouble with G6 sensors as well. Toward the end of 10 days (day 6 or after), the sensor drops out and sends a “no data” alert to my phone. It picks back up within three hours (the alert says to contact Dexcom after 3 hours of no data), but leaves me with no data for an hour or two. It does this a few times a day for the last few days of each sensor.

The adhesive on G6 is also shoddy - the tape starts to peel right after I’ve put a new sensor on and I haven’t figured out yet how to keep it all taped down. A friend has recommended putting OpSite over the whole thing (it has worked well for her) and I’m planning to give it a try.

My question for all of you – should I spend time calling Dexcom? I only want to be on the phone if it’s going to result in sensor replacements or some sort of solution for the data dropping off. I like a lot about the G6, but I’m thinking I should go back to the G5 if I can’t get these issues resolved. Thanks! Jessica


You should 100 percent call Dexcom. My experience is that they are extremely generous about replacing the sensors before the 10 days and it’s at the least data that can use to troubleshoot so that perhaps the next batch of sensors does not experience this problem. We in the end went back to the G5 but we’re on our last few days of the remaining transmitter, so we’re gingerly expecting to go back to G6 after this. I’m hoping that using them on the stomach rather than the arm may have solved the problem, but we’re not sure. It was pretty untenable before though.



Sorry in advance. My post got wordy.

The issue you are having could be related to the adhesive or it could be the sensor or it could be hydration.

My suggestion is to start with the easy stuff. (Which may or may not be beneficial but really no reason not to try.)

Get the tape from Amazon. $20. It lasts forever. We have a cardboard template we use that has a hole in the middle for the transmitter. Took a bit to make the template (easy if you are more artsy) but then it makes it quick and easy to get another tape ready for a new transmitter that has the hole in the middle so the transmitter is not covered.

I know some people cover the transmitter but we very specifically to not cover the transmitter or have any tape even touch the actual transmitter.

Put the tape on as soon as snap the transmitter into a new sensor. Do this for the next three sensors. Give it every opportunity to work.

If everything starts working awesome for you then super. All it needed was a bit of tape.

Also - keep track of your hydration for the next three sensors. Pain in the neck - sure. It is easy to be under hydrated and lack of hydration definitely causes issues with the sensor. If you are not peeing multiple times per day then you are not drinking enough. Obviously there is a balance and no need to get crazy. But still something to be aware of.

After three sensors if neither the tape nor hydration has done the trick and the sensor is still dropping out after day #6 and before day #10 then it may be reasonable to assume it is the sensor itself. Which is a serious bummer.

We are having similar issues although not as bad. We are consistently getting to day #8 and sometimes #9 or #10. Once we even extended the sensor and got to day #12. However most typically it is day #8 or #9 for us with good solid accurate data.

We use the G6 integrated with the Tandem t:slim X2 so as to drive the Basal-IQ algorithm. The Basal-IQ algorithm is a huge benefit to us. Huge. So I definitely want to make it work. I am not going to call Dexcom/Tandem for every sensor that does not make it to 10 days as we don’t need that many replacements. Technically I could and they would send them. But I would not feel good about doing that with no implications on what anybody else does. Dexcom specifically said for me to call them anytime it does not hit 10 days.

In any event, out of a 90-day order which comes with 9 of the G6 sensors, if we run them all at 8 or 9 days and call in 2 or 3 times for a sensor replacement, that will work for us.

BTW - Dexcom/Tandem are great in regards to Technical Support. They have never given me the slightest issue in regards to replacing sensors or transmitters. Sometimes they want the failed unit back and sometimes they do not.

As FYI - Dexcom has publicly stated they are working on a modification to the current sensor adhesive on the G6.


Grif Grips have been working well for us, if you want the more expensive but also more convenient solution than the tape.


Amusingly enough, I am calling in right now to Tandem technical support right now for a failed G6 sensor.
9.1 days.
Although day #9 was really crappy data but wanted to let this one completely die rather then pull early.

Also of mild interest. We just put the new sensor in tonight and the transmitter gave the final warning. This is the last session for this G6 transmitter. As of today it has been 96 days since the transmitter was activated. So if this sensor were to last for 10 days then we would have gotten 106 days out of this G6 transmitter.

We already received our resupply of a pair of G6 transmitters which came in last week so no issues there. There seemed to be no delay on the shipping of the transmitters.

EDIT: Very easy call with Tandem Tech Support. A person picked right up - no hold time. She wanted to know the exact message which I already had from the pump cgm history. I gave her the time of the sensor failure (from the pump cgm history) and the time of the session start (ie - pump cgm history). Verified this was day #9 (based on my reported start/stop session) and confirmed it did not reach 10 days so would be replaced. Gave the lot number of the sensor. She did not request the sensor to be returned. Tandem sends the order for the single sensor replacement to Dexcom where it will ship from one of their distribution sites closer to me. Tech Support said maybe a 5 day backorder or so on the sensor which was no problem for me. Will ship FedEx normal ground.

G6 sensors used integrated with the Tandem pump and which encounter an issue AFTER the 2 hour warmup are picked up by Tandem for support purposes.


I have been having the same issues with the G5 the last four insertions. I thought it was the batch number I had, but even the new sensor I got won’t read. I even got a new transmitter and still isn’t reading. I am wondering if it is the monitor. When I asked about that, I was told that it was guaranteed for a year and less than that I would have to pay for a new one. However she never sent me to that department to talk to anyone. I guess another call tomorrow in order.


I just started this weekend having sensor failure with my G6. I have had four straight sensor failures. The meter shows the two hour warmup starting but after a few minutes i get a message on the meter advising that there is a sensor error and a few minutes after that, I get a message saying sensor failure, replace sensor now. Dexcom is replacing the sensors but the techs are at a loss as to explain what the problem is. I was told to try a different alcohol wipe other than skin-prep to see if that makes a difference. Since receiving the initial 3 month order and a portion of the second order I have used a total of 14 sensors that all worked properly. So I am back on fingersticks and nightly alarms to check my numbers every two hours in order to avoid any lows.
The 4th and current sensor is still installed and I am letting it go for at least three hours to see if any reconnect takes place but I am not hopeful. I am going to talk to my Endo next month to see about going back on the G5 where I had zero problems. I was very happy to get the G6 but it has turned out to be a major disappointment.


They will send replacements for those sensors that don’t last. And they’ll send stickers to help stick them down.

@Thomas fascinating about hydration. I’ll pass it along. I’ve noticed we all hydrate less in the winter because it’s not hot out, but I never thought about the Dex.


This is interesting. Can you elaborate?


I agree, and try to make sure I drink enough. Definitely notice more wonky readings when I forget.


OK, several weeks ago I experienced a sensor failure, Dexcom sent a replacement but the tech advised that after the sensor is inserted, wait for at least 15 minutes before starting the sensor. I have not heard that from any other tech. So that is what I am now doing. Obviously I don’t have any way of knowing if this wait helps but so far my sensors have worked. Thought I would pass this on in case you want to try it. After all, you have nothing to lose by waiting before starting the sensor


I believe an issue can arise if insufficient time is between the stop of the old G6 sensor and the start of the new G6 sensor. This is a new issue which did not exist for the G4/G5 and is unique to the G6 system.

Allowing a minimum of 10 minutes between the stop of the old G6 session and start of the new session is sufficient.

Other than that (which likely is what the tech was trying to get to) the system has no way of knowing how much time has elapsed between the sensor being inserted and the session being started.

Assuming that we have ensured a 10 minute gap since the stop of the old session, we wait only a minute or two after G6 sensor insert. This is time enough to verify no “bleeder”, snap in the G6 transmitter and start the session which includes using the iPhone to take the picture of the sensor code graph.


Thanks for the info Thomas. What you described regarding the 10 minutes between old and new sensor makes more sense to me.