Dexcom-taking the plunge

@Tim12, I don’t ‘presoak’, but to solve the same problem, I insert it midday, and then spend some of the next few hours calibrating. Initially, I was inserting the sensor in the evening, which resulted in our sleep being ruined by repeated false lows, and if I tried to calibrate, repeated reminders to recalibrate.

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Give the presoak a try. I do a 12+ hour presoak and never have to do any calibrations.

Chasing the crazy fake low readings with calibrations right after an insert doesn’t help any because you then have to repeat the calibrations after the sensor settles down.

Thanks to EVERYONE. Very helpful. I plan to use my IPhone 7 to “read” the Dexcom and I would like to get a watch also to read it. From the postings, I understand that I need to get a watch that has “Wear OS” technology.


No. Since you have an iPhone, the easiest choice would be an Apple Watch. You would only need Wear OS if you had an Android. You could go with other watches, but I am not sure how well they would work, if at all, with an iPhone.

Apple has nice integration between the device, the app, and the watch, but there are occasional issues with upgrading your operating system, where you would need to wait until Dexcom declared it okay. There are a few recent posts about this. I will add them to this thread.

Dexcom Mobile & Watch Apps

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Know that there is a learning curve to being successful with Dexcom. Over time you will learn when to trust it and when not to. It is not perfect but for most of us it is a life-changing technology.


As promised, links to Apple threads…

I desperately wish that I had verified the readings against traditional machine, not just for the first two weeks, but always.

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Because of prior bad experiences with adhesive in a Medtronic and a Dexcom CGM, from over 5 to 10 years ago, I assumed that I would need an adhesive patch over the existing Dexcom patch, so bought a couple of varieties, just in case.

This time around, it has all gone well, no irritation, and the devices stay attached for the 10 days. I don’t try to extend the sensor life - I would if I erred in timing the prescription, or one was defective - but in that case, additional adhesive patches would be useful.

Hi Marie. Perhaps you can help me. When I had the G5 I had no problem restarting. I was only successful once with the G6. I watched all the YouTube videos. Have popped out the transmitter waited 15 minutes and restarted with same sensor number. Never works for me. I don’t used my receiver only my iPhone. Any tips? As for the adhesive. I use the liquid SkinTac. I put on my arm and then on the sensor adhesive. Never have any problem with it staying on. Thanks.

Most definitely, and as @MM1 says earlier in this thread, you can get overpatches (with a perfect txmtr cutout) free via Dexcom. They work fine and as far as I can tell are the same stuff as the adhesive film I’ve used for years (I’ve had good luck with Opsite Flexifix, but there are other brands).

@Jane16 Unfortunately they are changing tech all the time, so there is the possibility you have a newer transmitter that won’t restart. So far that hasn’t come up but? You might let us know if you are still unsuccessful what the first letter/numbers are.

Make sure you have either a sensor that expired or manually stop sensor on your phone.

Then you take out the transmitter And wait a full 30 minutes, then pop it back in.

Then start sensor with original code.

Those are the only 2 things I can think of that might be causing an issue?

If it still doesn’t work maybe someone else has ideas!

Thanks for replying Marie. Will try again Thursday when sensor ends. Fingers crossed. Everyone is so helpful. A great resource.

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I went the opposite direction, from Dexcom to the Libre, and an infinitely happier now. I found Dexcom to be seriously frustrating on a number of topics, but here are the ones that I wish I’d known.

  1. dexcom is significantly more expensive. The sensors and the little grey transmitter are all costly, compared to the Libre, which has less expensive sensors that last longer, and no transmitter required every 6 months, no 3 months, no …

  2. Dexcom does not seem to care much about their user experience, as demonstrated by how long they’ve been listening to complaints about various things without making changes to better them.

  3. dexcom does not let you turn off the “low” alarm. They make excuses for why that is but to me the existence of the Abbott Libre has shown that their excuses aren’t persuasive. The Dexcom I had would alarm for no good reason (for example, read 40 when meter showed 100), and the unrelenting alarms can’t be changed. You could eat food you don’t need or want or you could listen to alarms every few minutes and not sleep. Those were the choices dexcom left you with. So many intrusive alarms in the middle of the night led me to turn off my phone and hide the dexcom unit in a dresser under pillows on the opposite side of the house. How is that a good idea?? (And yes I know the 6 is supposed to be more accurate, and control IQ is supposed to be great, but I’m skeptical of anything dexcom says and anyway, it would only take one alarm for me to rip the thing off and throw it away).

  4. for people used to the Libre, living with the dexcom unit will require adjustments. You shouldn’t wear it on you arm because you’ll knock it off on a door, in clothes, on seatbelts. You may not have realized it but the Libre adhesive means you don’t have to bother with silliness like tape and over wrap and such.

  5. Libre lasts 14 days.

  6. Libre and tandem have announced they are working toward a partnership. For me, I’ll happily wait for the better company to sign on to provide Control IQ options with a CGM that doesn’t make me genuinely upset multiple times a day.

  7. oh, and last, I’ve heard that dexcom is now redesigning their stuff to work, and look, more like the Libre. But they didn’t bother to do that years ago. They are only doing it now because they see that a better product is coming, and customers aren’t beholden to them any more. For me, I’d rather support the company that did it right from the start.

I’ll stop there. If it were me I’d give serious thought to whether to make the switch - or, since there are lots of people who are happy to make do with the dexcom system, try it for yourself and see what you think.

What is pre-soak?

Hi Tiffany–welcome to TUD!

Pre-soak refers to the practice of inserting a new sensor for a period of time before activating it in order to give the filament more time to acclimate to your interstitial fluid. It seems to help minimize the erratic readings that tend to plague the first 12-24 hours of a new sensor. You keep the old one running until you switch over to the new one, so you basically have two sensors inserted during the “pre-soak” period, with the old one still sending data to the receiver while the new one gets acclimated. Times vary. Seems like 12 hrs is about the minimum for this to have an effect. My practice is to insert the new sensor when the current one gives me the 24-hour warning, and then make the switch when it runs out. You just remove the old one, swap the transmitter over to the new one, and start the new session as normal.

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I have restarted G6 sensors with 8G and 8J transmitters. I wait 20-30 minutes, and clean transmitter before putting back on. Make sure there is a stop sensor for first usage if you replace before time ends.

What doesn’t work for them is doing a transmitter battery days reset.


I used the Libre before I switched to a Dexcom. I do love the Dexcom a lot more than the Libre, but at first I only found it slightly better until I got more used to making it work for me.

  1. Cost, this is a game changer for anyone that doesn’t have insurance to cover it. Everyone can’t afford the Dexcoms cost in the US. What’s even sadder is in other countries the dexcom only costs them $175 per month for whatever they need, so it’s much easier to afford. But Dexcom is competing against the more popularly used Libre in the UK and Europe. But cost is hands down a decider for a lot of people.

  2. There are a lot of things that could be changed, but that’s not always so easy. It takes time to develop and make sure it’s safe per government regulations etc. So I
    don’t fault them on this as much, although I also know they are focused on expanding as fast as possible because Libre has so much of the market and new companies will be coming into the picture soon too.

  3. Not being able to snooze the alerts is one of my biggest complaints.

  4. I wear the Dexcom just fine on my arm, in fact I knocked the Libre off more than I have my Dexcom although I use Skin Tac on my Dexcom.

  5. Definitely I think it’s better the Libre lasts 14 days, but that is outweighed by those of us who restart the Dexcom and mine always last more than 20 days. You can’t restart the Libre’s although there is a way some are testing right now to do so. It’s on this site somewhere.

  6. I would not want to trust the Libre for dosing on a pump. The Libre was always off by 15-30 points. I used to have to make adjustments to dosing because of that.

  7. Pick whichever you like we all have our preferences for different reasons. I ended way preferring the Dexcom because of the ability to calibrate it within 5 points of accuracy and slowly narrowing the alerts to give me time to respond before I went out of range. My A1c dropped significantly because of that. And my TIR is 98% between 65-160 and 94-96% between 70-140.

They do have the new Libre coming out and supposedly it will be more accurate and have optional preset high/low alert I have heard. Abbot has said the sensors will be the same cost.

The Libre definitely wins hands down in cost when that is a factor. But the Dexcom for me wins because of the calibration and alerts.

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Sence 2016 I have only had one sesor delaminate.
1st you should make sure you skin is FULLY cleaned with alcohol wipes. Insert the sensor and then press around it to verify it’s adhearing to the skin. After inserting the Tx I wipe the area around with “Skin Tac” Then after a long term believe that the sensor/Tx combination is not full waterproof. In this case I use a piece of Tegaderm Film to cover the whole thing. Hope this helps.

I have been having a similar problem with signal loss not only on my iPhone but the Dexcom receiver. This has happened on the last three sensor. This seems to occur with with the last 48 hrs of sensor life. Loss of Bluetooth connection is not a issue durning these events.

What do you mean by “narrowing the alerts”? I’m guessing you start with a wide range before alerts kick in (70-180?) and then keep lowering the 180?