Stockpiling Dexcom G5 transmitters: how long do they last?

Sensors, yes, but I can’t get a stockpile of transmitters, so depending on where I am with those, I could be out of my Dexcom supplies fairly quickly. Personally, I could afford to buy a transmitter and would. But the statistics for American households are that almost half can’t cover an unexpected $400 emergency, so I don’t think that’s true generally.


I have about 5 extra at this point. Insurance covers one per 90 days, so I end up 3 weeks to the good every refill. I paid $200 for 2 privately when I first started Dexcom.


I’m envious. Because my insurance is a mess that requires reauthorization each time I reorder my next two transmitters, and because Dexcom each time bumbles the other in some way, I inevitably get my next transmitter within days of when my last one ends (and sometimes a few days afterward…). So I have no wiggle room whatsoever with transmitters, unless I buy them out of pocket.

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You must have the G4 then. You can’t stockpile G5s because the battery dies too quickly for aout 80-90% of the units :frowning:

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G5. They last a year after the “ship by” date, which means I can stick about 1.5 years worth.

I had several long discussions with Dexcom about it, because we have had many early failures. Finally, an agent that was escalated into the discussion (I think because he knew a little more) admitted that, when you start a transmitter 12 months after the manufacture date, they see 80-90% failures :frowning:

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Don’t be. My insurance currently covers only 1 at a time, but they will refill after 83 days. I don’t get mine from Dexcom directly.

Granted. Fortunately, they are under warranty, and Dexcom will replace it with a shiny new one :stuck_out_tongue:

I’m currently using a G5 transmitter that has a manufacture date two years ago and a “ship by” date one year ago. On the first sensor it started showing jitter in the graph on day 5, and gave persistent ??? on day 6. I didn’t know whether that was because of the transmitter or if something was off with that sensor (normally I get 12-16 days), so I put my old G4 transmitter (not yet dead) on that sensor and the sensor worked fine. On the new sensor the way out-of-date G5 transmitter is on day 5 and everything looks fine. But I don’t expect to get anywhere near 90 days of transmitter life.

Running the G4 and G5 concurrently gave me the exquisite experience of doubled alarms, which is why I took the G4 off after a few days. It was interesting to see how the new sensor registered more extreme peaks while the old sensor showed a smoother graph: I wonder if they lengthen the period of the noise filter as a function of sensor age.


I thought there was some rule that you had to have started the transmitter within 5 months of it being shipped to you or they wouldn’t guarantee it. Something like that?

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@bkh is right: I need to look at the exact timing, but if you are a day late starting on “that” period, they won’t replace it. It has come up several times in the past year on forum threads, and Dexcom verified it for me on the phone. I will check my exact notes and follow up later for precise numbers.

I’ve been told by Dexcom 1 year from the “ship by” date when buying from distribution, since Dex doesn’t know when it was shipped to you. For example, I just got one with an earlier ship by than the last one I got.

Officially, the warrantee is 3 months from start date.

@kmichel, @bkh, after re-reading my notes, this is what I got from Dexcom when discussing with them in the past couple of months as I was preparing for our long Euro trip:

  • the transmitter must be shipped to the customer within 8 months of the Manufacture By date (the date next to the factory icon on the box). The Ship By date is indicated on the box as SB

  • the transmitter MUST be started by the customer within 5 months of ship date. If there is any debates on that, Dexcom goes by the date the insurance paid for the transmitter

  • If that happens, then Dexcom warranties the transmitter for 90 days.

I was also told unofficially that, if you start the transmitter 12 months or more after the manufacturing date, you are very likely to run into trouble.

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@kmichel I have to agree with @Michel about the battery life of G5 sensors.

This is borne out of my tracking longevity of them with xDrip+ ( no artificial software imposed battery limits).

Out of two transmitters purchased at the same time and used consecutively, the first one lasted 193 days, the second one only 123 days.

Although this is just n=2 at this point it would strongly suggest that the transmitter battery wears out according to the Dexcom description.

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Probably, @docslotnick. However, I do have several spare transmitters and always work with the oldest of the bunch.

I had one go flakey in about 60 days, and they replaced it. I had my previous one to the current one flake out on day 90 (exactly) of use, and they would not replace it for obvious reasons.

I’m just going off of my experience with them. I’d still try to keep using them if I could not get more for some reason.


Interesting. My transmitter purchase date is coming up very soon and I’m stressed that “issues” will come up with my insurance or Byram and my current one will die before I get the new one. Which day do I start the last sensor to get the most extra days? I remember someone testing it but I forget the final result.

I’m thinking that it might be worth it to purchase an extra one out of pocket and always use the older one just so I can always be one transmitter ahead so I don’t run into unfortunate CGM gaps… Do you think that’s worth it?

Also, for taxes 2018 medical expenses are limited to 7.5% AGI then back up to 10% limitation for 2019… so if you itemize even with the larger standard deduction, it makes sense to push medical to 2018. And stockpile syringes and test strips for me. [then likely go to an itemize every other year schedule with charitable, property tax for me and many of my clients]

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I have found that I get exactly 3 sensor changes (at 1-week intervals) out of a transmitter once it first tells me it is going to die. That is assuming a good transmitter.

Since my insurance only allows 1 transmitter per refill, I bought 2 spares when I first started out and sold one of the two off (it was a 2 for 1 deal from a certain website not related to Dexcom). It really got me nothing but a sense of security for a long time. But I ended up needing it when a transmitter went wonky on me. It avoided having to wait for Dexcom to replace the wonky one.

If you look around, you can find a spare transmitter for about $200 +/-.

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From my limited experience, I have basically get a 6 month life on the G5 transmitter from when it shows up at my door. I posted some information on this from a Canadian perspective in another thread which is linked at the bottom of this post.

I made an attempt to always keep one G5 transmitter spare and stretched my first transmitter to 6 months using xdrip+ because my insurance only covers 1 transmitter every three months.

Dexcom Canada says (which is different from Dexcom US) - “Your transmitter is covered under a limited warranty for three months, starting from the shipment date.”


3 posts were split to a new topic: DIY replacing Dexcom G5 batteries?

Thanks everyone for your comments. They are helping me understand my recent shipment of two Dexcom G5 transmitters. If they only warranty the purchase for three months, why am I being sold a supply of two (2)? Every time I’ve received my G5 shippment it has been with two (2) transmitters (G4 we only got one transmitter per order). I guess time will tell if they will both work as expected and/or if I am able to receive a replacement transmitter free from Dexcom if it doesn’t. Again, thank you for sharing here! I feel empowered having this information and won’t be scratching my head as hard if something should go awry!

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