Questions for those with Dexcom G6

How much more accurate is the DEXCOM versus the Medtronic sensor. I am using the 670G and the MMT-7020A sensor and it’s accuracy is terrible. I rarely see the 20% accuracy that they state. The first day and day 6 and 7 are much worse, with many readings off by 100% (250 BG vs 100 SG). I am thinking of switching to DEXCOM and continuing with the Medtronic Pump (warranty not over for another year). Any recommendations?

I recommend UniSolve (

Thank you, the most pain he had with the sensor was removing it, hopefully this makes it easier.

In general, the Dexcom is very accurate. During times of good control, it is rarely off by more than 2-8 compared to fingersticks. When blood sugars are fluctuating, it will be off more due to normal lag time between blood and cellular fluids. Still, for me, it’s unusual for it to be off by 20. Plus, the Dexcom doesn’t go “off-line” all the time for recalibration, and insertion is painless. I pay cash price for Dexcom so I can run the Loop version of DIY Artificial Pancreas. I won’t spend my cash on Medtronic’s CGM - not after the first try, anyway.

  1. Where do you typically apply the sensor?
    This one is personal preference of course, what I have found is I hate the recommend areas because they are in my personal area and often hit or get bumped on items.

About, 6 years ago I started wearing my CGM in my tricep and it has been amazing. No reading issues here for me and I have been doing this for a long time from Medtronic, G5 and now G6. It’s not an approved area, so take it at your own test, but for me I never even think about it.

  1. How noticeable (to you) is the sensor?
    Do you always feel it on you?
    In my tricep, never notice it, never see it, never think of it. You might need so help inserting it the first few times, but I can do it on my own after a few times to practice. Plus the new G6 insertion device it like child’s play, not even an issue.

  2. Do the spots where you put the sensor every get irritated?
    Irritated, no, and I wear the sensor for 4 weeks in my tricep. I do get little spots on skin from where the injection site is, but I’ve been doing it so long I don’t even care. Plus I’d rather have a mark on my tricep than on my abs. But I’ve never had any adhesive irritations or sensitivity. But this is probably different from person to person.

  3. How good is the adhesive? I don’t swim but I like to run about 3-4 times a week.
    Here is the trick. Device is great. If you want it to last a long time you should put a tegadem A6258 and buy a tag punch out at Hobby Lobby that fits perfectly. You replace the tegaderm once a week and it will last forever. The longest I ever wore it was about 8 weeks, this was because of insurance issues. But normally 4 weeks. Never any issues

  4. Any major cons that you don’t like?
    I don’t like that they lock you out now after 10 days. This sucks. They say it was because of FDA, but I’m sure it was for profit. Here is a web site that will show you how to restart the device prior to the 10 day termination.


I have used the Dexcom G4/G5/G6. Overall, the G6 is a big improvement over prior generations.

  • Where do you typically apply the sensor? Abdomen and Back of the arms.

  • How noticeable (to you) is the sensor? Do you always feel it on you? - I don’t notice them.

  • Do the spots where you put the sensor every get irritated? No. I make sure to rotate the spots for each use.

  • How good is the adhesive? I don’t swim but I like to run about 3-4 times a week. I exercise regularly, which includes cycling, kayaking, other cardio, and weights. Generally, the adhesive sticks for 7-8 days before starting to come undone. I secure it with waterproof medical tape, like the J&J brand. Anecdotally, I have heard that products like Skin Tac help with the adhesion, but I have yet to try that.

  • Any major cons that you don’t like? Other than the fact that the adhesive does not fully last 10 days, no. Overall, I have been very happy using the G6, and do not at all miss pricking my fingers multiple times daily.

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Thanks Russell! Do you have a preference of Abdomen vs. back of arms? Is it easy to put on the back of your arms?

No, I don’t have a preference and both locations seem to work fine, at least for me, with the Dexcom 6 unit. As long as you can grasp the sensor insert and reach around behind your arm over the tricep, then you should be okay. You can always practice that beforehand to see how easily you can do that.

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Yes it’s easy, jut practice a few times and you got it. The G6 insertion device makes it a piece of cake, use to be much harder.

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How do you get 20 days out of a set?

  • Where do you typically apply the sensor? abdomen (upper and lower)
  • How noticeable (to you) is the sensor? see bump through clothing but, I wear a lot of stretch stuff. Do you always feel it on you? Never
  • Do the spots where you put the sensor every get irritated? sometimes some redness but, usually not w/ new adhesives
  • How good is the adhesive? Not great - doesn’t get you to even 5 days. Dexcom 5, never had a problem but, if I ran it over 7 days - I had to put something over it. I use an overlay - variety of types. The stuff provided by Tandem/Dexcom irritates my skin…yes, you need to request it and they will give it to you for free.
  • Any major cons that you don’t like? lose readings on every set and they can provide no advice - I use both the Tandem pump (like a receiver) and an IPhone 7. Tried to run data through my phone to my iWatch and that was too much. May try a new iPhone – but, that sucks to have to keep paying for something they say should work. In my experience, once you start losing readings you have maybe a day and in that day - the readings are useless – if you really need to know what your BGs are doing, take it off and call for a replacement.

…and just to be clear - the Dexcom CGM is more accurate than the Medtronic. I have not tried any other type. I want a CGM that works with my pump to reduce the risks of low blood sugars and can be upgraded to closed loop. I may jump back to Insulet Omnipod in 2020 when they go closed loop. Right now, nothing works as good as we need it to work. Bigfoot might be the best in development but, not available for a few more years…if it becomes available.

I use the Spike app. It is Apple-only, and by request only via It replaces the Dexcom app - you can’t use both. With Spike, there is no 10-day sensor timer and no 90-day transmitter timer. You just keep using them until they become unreliable. The Spike app requires one calibration per day, preferably during a “flat line” period when blood sugars are not fluctuating. I find it slightly less accurate than the Dexcom app, but at $130 per sensor I will live with that to get the extra life…

Hello Brian,

I have been a diabetic for 15 years. I started wear the pump last year and Freestyle Libre for 2 years. I changed to the Dexcom G6 as of last Friday.

So far the Dexcom is great and hardly noticeable. I am using Skin Tac to keep the sensor attached with no issues.

I also wear a special tank top t-shirt with pockets to carry my pump. It is very discreet.

Does the SkinTac also protect your skin? I have been having issues with the CGM adhesive irritating my skin, and it takes a while for the skin to heal. I usually swap between both my legs, since I wear a omnipod on my arms and stomach.

@emfeller, I don’t think Skin Tac protects the skin. It just makes it much tackier so that the adhesive from the sensor (and protective patches like GrifGrips) stays on for longer. If you want to protect the skin from irritation, Adam Brown of diaTribe has this recommendation:

“If you get adhesive allergies, try spraying Flonase on the skin before inserting the sensor. Others like educator Gary Scheiner recommend applying a Band-Aid Tough Pad to the skin first, then inserting the sensor right through it.” diaTribe CGM Tips.

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Legs, arm and stomach. If I put a G6 on my stomach they tend to come off really fast. Next time you get a dex shipment ask for adhesive patches and they will send you a clear adhesive patch which works 100% awesome

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