For the last two weeks, I got to try the Freestyle Libre 3, the newest continuous glucose monitor (CGM) in the Libre product line. I think it’s the best CGM I’ve ever used. I prefer it to my usual CGM, the Dexcom G6.
You might not need to wait to try it yourself. Though Abbott, the Libre’s manufacturer, didn’t make a big deal about it, the new CGM is now available in the United States at select pharmacies and durable medical equipment vendors. It’s worth hunting for.
For some readers, though, there may be one big catch: interoperability. More details below.
Abbott provided me with a complimentary sensor to try for this review. But my opinions are all my own.
Size
The size of the Freestyle Libre 3 sensor is an absolute triumph. It is tiny, light, and thin — about the size of two pennies stacked on top of each other, according to the company’s marketing. It is light as heck. It’s hardly more obtrusive than a Band-Aid.
The author, barely aware of his CGM sensor
I’m used to the Dexcom G6. It’s pretty sleek and I wouldn’t call it a real bother, but I’m always aware that it’s stuck to my belly or arm. But the Libre 3 sensor, which is worn on the arm, is so small and so unobtrusive that I literally forgot it was on my body. I’m wearing a device but it doesn’t even feel like I’m wearing a device. To me, this represents a huge quality of life improvement, and reason enough to love the Libre 3.
Sensor Life
The Freestyle Libre 3 is rated for 14 days. After a few early bumps in the road, as discussed below, my sensor seemed highly accurate up until the very end of the 14th day.
The adhesive also performed perfectly for me; the sensor stayed secure for 14 days without a hint of weakness. I did not push it to the max (this wasn’t a sweaty summer and I didn’t go swimming), but at least for now, I see no reason to supplement with special tape or patches.
Dexcom has promised that they’re doing everything possible to extend their sensor life from 10 days to 14 days, but the G7 — which just launched in several countries outside of the US — still has a 10 day wear length, at least for the time being.
Application & Start-Up
Sensor application was painless and nearly effortless for me. You press the one-piece applicator directly against your skin, press a button, and boom, the sensor is on your body. No messing with stickers, no exposed needles.
Start-up was simple. Once you pair your sensor with your smartphone (a seamless process) it gives you readings in one hour. For comparison, the Dexcom G6 takes two hours, but the new G7 will only take thirty minutes.
Basically, the system was very easy to get up and running. Technophobes don’t need to worry.
No More Scanning
If there was one obvious sticking point with the previous Freestyle Libre CGM systems, it’s the fact that users didn’t just get their blood sugar numbers automatically beamed to a dedicated receiver or smartphone. They had to manually scan the sensor by holding their device over the sensor for a few moments.
Scanning is unnecessary with the Freestyle Libre 3 – your smartphone will update with new blood sugar readings automatically. Abbott’s promotional material has not stressed this point, perhaps in an effort not to disparage the Libre 2, which is still fairly new and still selling well. But to me, it seems like one of the most important improvements for the new device. In our survey of CGM users, manual scanning was frequently mentioned as a major annoyance with the older generations of Libre CGMs.
Another bonus? The Libre 3 will provide new blood glucose readings every 60 seconds. That’s easily the best on the market.
Smart Phone App & Other Features
Gone is the FreeStyle receiver, a dedicated device that was used to display glucose measurements with older versions of the system. The Libre 3 sensor connects directly to your smartphone:
Ross Wollen
The Freestyle Libre 3 brings many other features to the table, some of which were introduced with the Libre 2 model:
Glucose alarms
Glucose trend arrows
Remote monitoring for family members/caregivers
Data sharing with healthcare professionals
Data analysis in the smartphone app
I was quite happy with the app, which presented all of the glucose measurement data I wanted in an intuitive fashion.
Accuracy
When it comes to CGM accuracy, I’ve got two main questions:
Is it good enough that I can stop using fingersticks? And does it bombard me with false alarms?
I was very pleased by the Libre 3’s accuracy. Throughout the two-week session, I would randomly check against my old-school glucose meter, and the readings were always at least in the same ballpark. I felt confident using the Libre blood sugar measurements to guide my eating and insulin dosing decisions, which is really all I can ask of a CGM system.
I’m not gonna lie, the first 48 hours were rocky. During my first night sleeping with the sensor on my body, my phone woke me multiple times with blaring low alarms when my blood sugar wasn’t actually low. It was bad enough that I moved my phone out of the room so it would stop disturbing me — which completely counteracts the safety feature that makes the CGM so vital for people with insulin-treated diabetes. On day two, the measurements were much steadier, but there was a consistent gap between my meter and my Libre 3, and I thought it would be smart to recalibrate my sensor. That’s when I learned that, to my surprise, the Libre 3 cannot be calibrated.
I didn’t need to worry. On day 3, the sensor found its footing and delivered highly accurate readings for the next 11 days. I didn’t get hit with a single false alarm. In fact, it performed even better for me than the Dexcom G6, which, despite its generally high performance, does sounds false alarms and randomly drop Bluetooth connectivity.
That brings me to a third question: how accurate is it during blood sugar rollercoaster events?
I decided to put the Libre 3 to the test by going on a strenuous hike. For me, this means eating tons of carbs to counteract the extreme increase in insulin sensitivity that I always experience with cardiovascular exercise. I wanted to see how accurate it remained while my blood sugar was diving up and down.
It did … pretty well. Sometimes my glucose meter and CGM were off by some 50 mg/dL, a significant difference. But that was to be expected. CGMs are known to be less accurate during periods of increased glucose variability — a steady blood sugar is easier to measure than a fluctuating one — and even if they were perfectly accurate, they’d always lag about 10 minutes behind a glucose meter. But none of the readings were absurd, and there were no false alarms. The overall performance was at least as good as what the G6 usually gives me, and probably even better.
Both Abbott and Dexcom, with its upcoming G7, claim to have created the world’s most accurate CGM. I can’t judge the accuracy of the G7 yet, but I’ll take Dexcom’s word for it that it’s even better than the G6. My hunch is that trying to distinguish between the accuracy of the G7 and the Libre 3 will be like splitting hairs. Both are certain to be good enough to leave the fingersticks at home in most circumstances, which is really all you can ask for.
Cost
Given the vagaries and complexities of healthcare economics, it’s difficult to say exactly what any one patient will pay for a Libre 3. For those of us lucky enough to have generous health insurance policies (or live in countries with robust socialized healthcare systems), the Libre could be practically free. For some of us, it may be prohibitively expensive.
But we can say that the Freestyle Libre products usually cost less than the competing Dexcom products. That’s been true for years, and it’s not likely to change. Abbott is promising that Libre 3 will cost exactly the same as the Libre 2.
Abbott is doing what it can to get insurance coverage for patients with type 2 diabetes. CGM technology can be vital for patients with type 2 that use insulin – and even for those without a major risk of hypoglycemia, it can be a wonderful tool for optimizing blood glucose levels.
The One Catch: Interoperability
The Freestyle Libre 3 has not yet been approved in the United States for use in a closed-loop automatic insulin delivery system, not with the Omnipod, the Tandem t:slim, or any other insulin pump. Why? It appears that the sticking point is that the FDA believes that the Freestyle Libre sensor may give inaccurately high blood sugar readings to patients that consume high doses of vitamin C.
Abbott, naturally, is working hard at removing that warning label. In June, an Abbott spokesman told me that they hoped to clear up the issue by the end of 2022, though there’s no telling how quickly looping approval will follow.
The Dexcom G7 probably won’t be approved for closed-loop systems right out of the gate either, but it seems probable that it will get there before Abbott does. In the meantime, loopers in the United States now are limited to the Dexcom G6 (or the Medtronic system).
Bottom Line
The Freestyle Libre 3 is here and it’s legit. The new CGM is competitive with (or better than) Dexcom’s product in almost every way, even while coming in at a lower price. It’s the smallest and least obtrusive CGM ever, and has all the features you want, including automatic minute-by-minute updates and 14-day sensor length. The Libre 3 arguably sets a new gold standard for continuous glucose monitoring technology — but those who use a CGM as part of a closed-loop insulin pump system will need to wait before they make the change.