Libre 3 vs. Libre 2?

Hey ya’ll. I’ve been using the Libre 2 with my Android phone as a reader for several months, with pretty good results. I use Juggluco as a Bluetooth collector, which shares to Xdrip+ on the phone. There have been a number of sensors which started accurate and ended inaccurate (30-50% off), and a few which became grossly inaccurate and usually self-terminate the sensor session. I’d say the failure rate was 20-30% overall. To Freestyle’s credit, they have replaced the bad sensors without complaint.

Libre 3 is now available in my pharmacy. I understand Libre 3 still activates via NFC but now communicates with the app via Bluetooth without the need for intermediate apps or devices.

I’ve waited for this for a long time, but have some questions/concerns:

  1. Is it as accurate or more accurate than Libre 2? I realize the delay and other challenges with interstitial fluid vs. BG readings, but the Libre 2 (and Dexcom) were often within a few points of true BG, especially early in the sensor life. BTW: I test BG using a Contour Next One, which I take to be accurate based on @Eric 's and others experiences here.

  2. Is it more reliable than Libre 2?

  3. Does it permit calibration? In my use of Dexcom, the sensors seemed to have a lower failure rate, which I attributed to calibration. I think a number of the “failed” Libre 2 sensors mentioned above could have been rescued by calibration. Unfortunately, the Xdrip calibration was only good for up to 20 pts correction, and usually is inadequate after a day or 2, as the sensor drifts farther from reality.

  4. Does it allow communication to an app such as Xdrip, Juggluco, Nightscout, etc? I’m not optimistic about using the Libre3 app: I’m expecting a half-baked app with the bare minimum features and very few available user customizations.


I’ve been using Libre 3 for just over a month now (I’m on my third sensor).

Yes, it seems more accurate than Libre 2 and with less of a delay. My first Libre 3 sensor read 10 mg/dL higher than finger pricks, and my second and thirds sensors read 10 low.

I haven’t had any sensors fail (but I’m only on my third one), but the third sensor did take longer than usual to get in line with finger pricks (about 2.5 days from application).

Unfortunately not. Besides the fact that it’s a true CGM, not a FGM, and no scanning is needed besides activation, everything is pretty much the same in the app and reader as Libre 2. There are a few little differences (you can set two ranges and it give GMI rather than predicted HbA1c), but nothing earth shattering.

I don’t use these, so I’m not sure. I found the Libre 3 app alarm sounds terrible and they cannot be changed (not the sound and not the volume), so I use the Libre 3 reader.


Hi @Finn ,

I use alarms from xdrip+ and Juggluco, and disable the libre app and alarms after activation of a sensor. The aforementioned apps have much better alarm settings than the libre app.


Good to know.

I’m pretty content using the Libre 3 reader for now, but I’ve seen several people mention those apps on here, so it’s on my radar.

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Type 2, 63 y.o. lummox.

I had very bad luck with libre2: >50% failure rate out of the box (Abbott replaced them all, but still a PIA, because there is a wait and my insurance only lets me get 2 at a time - fortunately, I have a good relationship with my pharmacist and he would always spot me one when I was in a jam). My endocrinologist claims I am the only one of his patients who experienced this problem regularly, and it may have been my own fault - pressing the applicator too hard upon installation - easing up and letting it do the work helped a bit.

I switched to Libre 3 a couple months ago (I’m on my 5th or 6th?), and have been much more satisfied; not one has failed out of the box, plus the readings are much more reliable (at first) BUT, I have found that they start to fail after 10 or 11 days and give me low glucose warnings when finger pricks show 75-85, and fail completely and ask to be replaced by day 13. Not one has made it the full 14 days. Other than that (and the fact that they are 3x the price on my insurance plan), I’m much happier overall with the 3 vs the 2. I DO like that it monitors constantly - you don’t have to actively scan to get a reading.

FWIW, YMMV, just my $.03 (inflation), IMHO, etc., ad nauseum.

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Ok, so I’m on day 14 of my first libre 3 sensor… It’s been great, accurate from the beginning, and even accurate today! Much better Bluetooth connection, no dropping signal at critical points, I’d say it’s a huge improvement over the previous generation!

Factory phone app is terrible, BTW. Good thing there are better alternative apps out there


My needs are no doubt different than yours, but the factory phone app is more than adequate for me. Plus, it shares my info with my endo in real time, just in case I ever need a remote consult, and he’s got my whole history on his computer when I pay him a visit. Maybe the other apps do that too, but this is the app he told me to use when he first prescribed the Libre, and I’ve had no issues with it (the app, that is - sensor issues are a whole separate topic, already discussed in this thread and elsewhere).

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Hi @Strat1117 ,

I stated that too strongly… The factory app is way better than having no alarms at all, and it’s really simple to use.

I prefer to have more customized experience allowed by other apps, which better fits my situation, providing the following functions, for instance:

Ability to control alarm ringtones, and whether they’ll override phone’s silent or vibrate modes

Ability to add additional low or high alarms with different ringtones at different thresholds

Prediction of future low, and alarm for future low if desired, etc… (and more features related to predictive simulation)

Fall rate alarm.

BG reading in status bar on my phone, without clicking to read the BG. BG on the lock screen, so someone nearby sees BG without fingerprint or password.

Those are just a few things that are really really nice to be able to use and configure, that I believe are lacking in the default Libre app.

I’d really really like to see an “advanced user” mode in the libre app that can be toggled on by the user, providing some or all of those things…Or at least the ability to share the sensor data with other apps! But I don’t think that will happen… I suspect it has something to do with concern for liability, etc. So we’re stuck with an app that has a 2.6 Star rating on the play store.

I have more thoughts, but I don’t want to carry on here. I’m planning to contact Abbott separately with suggestions.


[Begin Rant]

Grrrr! After touting how much I preferred the Libre3 to the Libre2, my Libre3 failed yesterday, 5 days early, for absolutely no reason (I was literally sitting on the couch working on my laptop - I didn’t bump it, bang it, thump it, pull it, catch it or do anything that could have caused it a ‘trauma’ of any kind). They are sending a replacement, of course, but what a PIA! I’m hoping it’s just an anomaly - this was my 9th(?) Libre 3 and the first 8 were mostly fine - but I just can’t go back to the same 30+% failure rate I experienced the Libre2. It blows my mind that they (Abbott/Dexcom) continue to get away with this nonsense. Oh well, I suppose it still beats pricking your finger.


[\End Rant]

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Hi, im T1 since I was 9. I started using Dexcom in '09, though it failed 2 sensors in 2 days and theyre sending me a replacement or 2 (should check on that though all this cra* in the past few days makes me pause to call again UGH!).

SO, today is early Sunday, and the last sensor+pod failure coincided, oddly, early Friday morning. Then today, earlier on Saturday, my pod failed [again].

Due to the Dexcom failure, I’d begged Dr for an Rx for Libre, she argued “because it’s not Omnipod compatible,” [grrr, DUH!] then prescribed it. So, for me this “Libre thing” has been a BAD cgm trial, so far.

I’ve been fingerpricking throughout to check [going on 4 hours now, BOO!], and initially BG was rising, in spite of 0 feed all day, while stacking insulin via Omnipod. (Finally replaced, and saw pink on the adhesive fabric, but it was dry, a separate mystery)

Libre kept reporting rising bg #s.
Finger pricks were reading 50-60+ pts lower, eg:
10:26pm Libre 389 L vs 337 fp
10:46pm 395 L vs 358fp

11:11pm Libre app over 400 + out of range while NEXT to it (phone app) vs 350fp

11:44pm Libre app over 400 + out of range while NEXT to it (phone app) vs 342fp

12:28pm Libre app over 400 + out of range while NEXT to it (phone app) vs 350fp

I’m running out of STRIPS, and Dexcom not arriving til Tuesday after Memorial Day. Yikes! I can’t keep doing this since Friday night!!!

But, so, my initial foray into using Libra v3 tells me no, NOT for reliable Type 1 use!

Not to mention… you’re DISALLOWED from calibration? How CAN that be useful, to ANYONE?

On the persistent high note, I’ve tried:

  • not stacking
  • stacking
  • walking
  • drinking tons of water
  • bolusing w syringe

Scary bad… 】bc at this point I can’t go to sleep either [single live alone heavy sleeper, sans diabetic alert dog], afraid of a Friday morning repeat bad low due to earlier stacking. I hope the night is smooth!

@Jennifre Sorry you’re have the issue. I can’t offer any tech help as I don’t use Libre, just the G6. That said, I can’t help but think going back to the basics/first steps is what’s called for, i.e. verify your ICR, ISF, CF, and get your BG down in an acceptable range. As your finger pricks are high as well as the Libre/dex, and presuming the meter you’re using is relatively reliable, it seems your insulin levels need significant change. I don’t think your first goal should be getting the finger pricks and Libre/dex to match/be close, your real effort should be getting your BGs down into an acceptable range first and foremost.

You’ve been at this far longer than I have and I may not understand all of your situation, just my two cents (and worth the amount!).


@Jennifre ,

Libre 3 user here. Sometimes the sensor is accurate right away after initial warmup. Sometimes it takes a half a day for the accuracy to improve. Sometimes, the sensor never gets accurate. If the sensor never becomes accurate after a few days, I call customer service for a replacement.

I concur with the advice of @TomH though, gotta get the other aspects of diabetic management under better control as a first priority.


Thanks @mike_g and @TomH, I appreciate your responses! Yeah, I’m a temporary Libre3 user given my insulin pump is tied to Dlexcom6. I needed it bc two Dexcom sensors failed the other day and this holiday weekend won’t allow replacement delivery til tomorrow, Tuesday.

Since yesterday I’ve been fine. Though, based on your comments I’m curious: are you trying to tell me that you’ve never run into a “persistent high”? … And if you’ve never run into that, I DO want to ask you: HOW!!! I was high-ish, and picked up the Libre 3 from pharmacy, then it kept rising, while I continued not eating. Grrrr!

@Jennifre When I first started, having sensors fail caused me some concern…will i have enough until replacements arrive?! i found that with a 90 day supply (what my insurance provides, though I imagine I could get less), I had sufficient sensors to provide for needs until replacements arrived. Over time, due to replacement sensors, i built a small “backlog” to ensure my needs were covered.

As to persistent high’s, yes I’ve had them. My take is I miscalculated the carb load or failed to pre-bolus sufficiently for a higher carb meal and once I break 180 or 200, it does seem to take considerably more insulin and/or time to get it back down. Example, if I’m at 180 and don’t have at least 3 units on board, it ain’t coming down anytime soon and will be a matter of 4+ hours, I have take the bull by the horns and treat more aggressively….but not too far as then I’ll be treating a low and getting into whip-saw territory.

I appreciate your attitude of “not eating”, and usually avoid it, but have had the experience of “it’s time to eat” but being too high to eat (though this may be more mental than actual.

All of this said, the description you wrote, if not a one off situation, sounds more like a need to get back to basics of testing to ensure your treatment needs haven’t changed. I sincerely hope you’ve found and corrected the problem.


Yes yes yes, I can see by your writing that you understand the pesky persistent highs – BLECK! ONE good thing about the Libre 3 is that it SCREAMS at you if hight [or low], so you’ve GOT to attend to it, lol!!

“Breaking” 180-200 definitely DOES seem to be the look-out wall. Yuck! That is when it tends to get [more] persistent. :frowning:

I simply tend to FORGET to watch any CGM I’m wearing as often as I should. Hence, also, I have to say, I truly wish the Libre allowed calibrations – that just seems… silly, no?

But thanks @TomH, and @mike_g. I love this [PERFECTLY titled] forum, THANK YOU for it!! If you ever need any moderation help, I’m intrested. Have worked online since 1998. Have a great day!

*Still a VAST difference between CGM readings at the mo (280 Libre vs 222 Dex vs fp 240 (post donut)). Though FDA allows for 20% variaility to count as “accurate” so… FUD! :slight_smile: