Why are my G5 sensors not lasting as long?



I have […] been having sensor problems with the G5 for about 6 months: before, I could make them last 10-14 days, but in the past 6 months I have been having a hard time getting them to last just 7 days: we have to ask for a lot of replacements. This is weird because I am not any thinner than I was (although I don’t have a lot of fat).

[EDIT: copy pasted from another post to split a thread]


@Kaelan, I suspect there was a manufacturing process change, because a lot of us started having problems around the same time. We used to get up to 30 days, and suddenly it was hard getting to 10.

Repeated Dexcom G6 failures

I never thought of that. That would explain everything. I have been wondering really hard what I was now doing wrong.


When do you think that change occurred?


If I had to guess? July/August? Or maybe June.


That’s good to know. Thanks.
I haven’t placed an order since May because I had a few weeks of G5 supplies saved up that I wanted to use before starting the G6. I’ll be starting on the G6 soon, and I’ve been worried about having problems after reading some of your posts.

If the G5 is having problems anyway, then that’s not a great backup option if things don’t work out with the G6. Knowing that might help me be more patient with the G6 is problems do arise.


I agree with @TiaG, it was this summer when we started not being able to get a long lifetime with the sensors anymore.


That is true for us too, but our sensors must have been at least 3 months old. So for us that would put the shipping of the sensors back to March or so.


My new batch of G5s, which I received in July and just started, have also been more quirky and not lasting as long…


I opened a new box last month from a July order in Canada.

I used to get about 21 days on a sensor. Now I am getting around 14.

The “old” sensors would generally start to fall off before they every gave me weird readings.

The new sensors are falling off at about 2 weeks and the readings are a bit suspect if I try to ride it out.



Significantly Past the point at which I consider it coincidence.

I would consider a more reasonable explanation to be a very minor change in the G4/G5 sensors which were not expected to cause an impact.

(Note: We have switched off the G5 and are now on the G6 which is a different sensor)

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.”

Decision Date: 11/14/2017
“New supplier of raw material for the manufacturing of blood glucose sensor probes. The probes are components in Dexom G4 Platinum Continous Glucose Monitoring System and the Dexcom G5 Mobile Continous Glucose Monitoring System.”

Not saying THIS (or these) are (or are not) the reason for the change in behaviour as we have seen and as @Kaelan also has described but certainly this clearly shows there are minor changes that happen with these systems which are not generally reported upon. Given that we had very similar happen to us on the G4/G5 after going a VERY long time and being very consistent in getting 12 or 13 days on a G4/G5 sensor and then suddenly getting shaky data on day #6. Yeah. That is a big change.

Repeated Dexcom G6 failures

Can you and @Kaelan share the expiration dates of these recent cases?
My assumption is that I’m using sensors that expire EARLIER than that, then I haven’t yet reached these more recent sensors.
I am getting 14+ days with G4 sensors that have expired, or expiring soon.



May 2019


Ours expire in June 2019. Practically the same as @Thomas.


Thanks. My current sensor has expiration date 10/2018, now on day 13. I will use a newer sensor next, so will be interesting to if it has shorter life.


maybe it is more an issue of odds?


You are correct, and getting very wise in your young age.

So maybe I will have to use several “newer” sensors before making conclusion.

But it has been several years of using G4 sensors averaging 14 days or more. I can only make conclusions on my own experience.


That’s a disappointing change. I ordered my last box in April, and the sensors averaged 40 days. My new box, received a week ago, expires 09/2019. Just entering my second week with the first sensor, so it’ll be interesting to see if it has a much shorter life.


That’s amazing! I think my max was around 21 days.

What’s your secret ??


I think it’s just luck. I’m not doing anything special. I always use my abdomen, about halfway between the navel and the side, so there’s not a lot of movement. I keep the sensor taped down well, and never let it get wet. That’s it.