Why are my G5 sensors not lasting as long?



I haven’t used abdomen in a long time, as that is primary location for infusion sets. Will give it a try.


do you never shower? Or just put some kind of waterproof barrier on it??


Ha ha. Well, I work at home, so there are days … But yeah, I tape a ziploc sandwich bag over it – just along the top edge; I don’t seal it completely. Since I started doing that, I’ve never had the ??? I often used to get after showering. But I gather getting the sensor wet isn’t an issue for most users.


Yeah - We just ignore it. No special treatment.


Bring me up to speed on this issue, please.

Is everyone talking about the adhesive? Or the quality of the readings after a certain time?

FWIW, I have rarely gotten much more than 7 days out of any sensor, ever.


So that sensor ended today (16 days) and I started a new sensor with May 2019 exp.

@Eric, one theory is sensors with later exp date seem to be getting shorter life, for those usually getting more days.

Except @Beacher, we don’t know what’s up with that.


My last G5 box expires 03/2019, and I wasn’t experiencing any of the described problems.


Not related to adhesive. Quality of the reading.
We used to get 12~13 days of very good readings from the G5.
Quite consistently.
When the data goes bad, it is blatantly obvious to me.
It is also blatantly obvious when the adhesive is not working well.

We found that quite suddenly, we were only getting 6 or 7 days of good data from the G5.

I was wondering if it was possible that the sensor had been slightly modified perhaps entirely unintentionally so as to cause the change.

I noticed a change listed per FDA as:

For example, PMA Supplement to the Dexcom G4/G5 cgm system:
Decision Date: 06/15/2018
“Addition of a new supplier of glucose oxidase for manufacture of glucose sensors for G4 Platinum and G5 Mobile Continuous Glucose Monitoring Systems.”

I do not believe the sensor boxes have date of manufacture. They do have date of expiration.

Our boxes we last used had an expiration date of May 2019
@Michel boxes where they also were seeing a reduction in how long a sensor would last had an expiration date of June 2019

We have since switched to the G6


One small data point. I’m on my second G5 sensor from a box with expiration 7/27/19. The first sensor ran for a typical length of time, not notably shorter.


Sounds like we are the exception, but we hardly ever have issues with our sensors (G5). In fact, I can’t remember the last time we didn’t get at least 12 days from a sensor…most of the time 2 full weeks. Maybe we’re the only ones getting “the good batches?”

On second thought…maybe the issue is that I’m still using the OLD SUPPLY of sensors??? Maybe when I get up to the stock that was built in the timeframe being discussed we will see more issues (crossing my fingers not)

New Normal - Higher TDD = Shorter CGM Sensor Lifespan?

It happened pretty suddenly for us. i.e. we went for 1/20 sensors not making two weeks, to all of a sudden 17/20 having failures around the end of the first week. This was evidenced by the signal suddenly getting very noisy and not tracking as well as we were used to. We used to not get that “cloud” behavior until the 3rd week.


Well, we can join the bandwagon here. For the past two changouts, our sensors have only lasted about 8 days. Although it took us longer to experience this, we’re pretty sure it’s because we were using up all of our ‘old stock’, and just now getting into these sensors that people have reported these issues with. This sucks!


I have a question for all of you who had this problem back in November…has the problem fixed itself - aka - moved into new batches that are working better? Or have they remained bad and only lasting 7 or so days since you reported this issue back in November?


So, for us, we are now on the G6 and they are working much longer now that we’re using the belly rather than the arm. But…they are all limping to the 10-day finish mark. The last one died at 10 days and 2 hours, haha. The one before was like 9 days and 23 hours. So my sense is that they don’t last as long. However, ours also peel up before the 10 days is up, and Samson really hates having all the stickies on him so we don’t put on the overpatch until it starts to peel up. So I do wonder if it would last longer if we were more meticulous about gluing it down.


The problem is not fixed for us in the sense that we have never gotten back to last 10 days-2 weeks. But the past couple of months we have had somewhat fewer problems. We can make more than 50% of our sensors last a week, which is a lot better than in November. I am not sure why though: it could well be that we have somewhat adapted to new conditions :frowning:

At this time I think that @elver and @thomas are right: formulas have changed :frowning: But I could well be wrong and it could be that we have changed. Teens go through such changes. I wish I could give you better answers.

In fact, I figure that adults out of puberty would be able to use more controlled conditions to evaluate if new batches are better. Hopefully some will :slight_smile:


I don’t think they improved. I am able to make my sensors work better than a few months ago, but I have to work really hard at it: super careful with Skintac and more adhesive, a great job applying the sensor adhesive and the grifgrip (or other), exactly the right locations with the most fat etc. Even then, probably close half of my sensors don’t last a full week. But most of them last 5 days, which is better than it was.

The sensors that make it to a week rarely don’t go past 8 days. It’s become my new max, and it is not even worth it because the last day they peter out and I miss peaks I shouldn’t. So I pay for the extra day with worse BG.

But it is really hard for us to get replacement sensors to Europe. So I have to make mine last as long as possible.


I just killed a G5 sensor at 31 days.

It was still very well stuck with skintac but I was starting to see a bit of sensor noise although it was following my BG meter very well still.

They seem to be working well for me again.

EDIT: It has been cold here so I have not been sweating that much.


Canadian sensors are just better :slight_smile:


Or maybe it’s our climate? No, really. Less temperature variation (at least where @Aaron and I live).

I typically get 30 days out of a sensor. Occasionally only 14 or 16 days. I’ve had no problems lately. Mind you, I’m not using the latest batches of sensors, so that could be why.


I think that’s a good theory but…we live in a place where average temperatures fluctuate about +/- 10 degrees Fahrenheit from coldest to hottest, and Samson was struggling to hit 10 days. So at least for us the climate isn’t a big benefit.