FreeStyle Libre vs. Dexcom G6: Best CGM for Non-Diabetics
Discover the best continuous glucose monitor for your health journey: a comparison of cost, comfort, and usability.
There are many, many comparisons of these two devices but most are for those with Type 1 or Type 2 diabetes. This comparison is specifically for those with fully-functioning pancreases.
Quick backstory
As a “pancrea-normative” person (one with a fully-functioning pancreas), I am fascinated by CGMs and their value to those outside of the diabetic community. I have been using the Abbott FreeStyle Libre sensor for many years and more-recently, the Dexcom G6. Below is my personal experience with both.
The Sensors
Size
The most notable difference between the two sensors is size. The Libre is significantly thinner than the G6. This is because of the G6’s Bluetooth transmitter that sits on top of the sensor. The Libre is NFC-based, which means you’ll have to scan it with your phone. More on that below.
Application
The Libre is very easy to apply. Unscrew the applicator, snap it into the sensor, apply to body. Abbott recommends to place the Libre on the back of the upper arm. They do not sanction any other placement.
As a seasoned Libre user, I was surprisingly intimidated by the G6. I watched many application videos before the first time I attempted to apply it. The applicator is about twice as large as the Libre’s. The adhesive around the sensor is also much wider, so there is much less room for error.
Before you apply your sensor, you first have to note a sensor code on the adhesive sticker, peel it off, and save before application. The applicator also has a safety tab, which you remove before applying.
Once, the sensor is applied, you must insert the transmitter into the sensor and make sure it’s paired with the app. It’s very involved.
Dexcom recommends placing the G6 on the abdomen, back of the upper arm, or the buttocks. Most people opt for the upper arm location.
As you can see below, there is a stark contrast in size, especially for those with smaller arms. It’s easier to forget you’re wearing the Libre because of the size. Both should be worn with a cover to protect the sensors.
The adhesive on the G6 is extra wide, and the covers stick to it. I would recommend something like this to put in between the adhesive of the sensor and the adhesive of the cover.
Data Transmission and Storage
The Libre requires a manual phone scan using NFC. It takes readings every minute, and a sensor memory of 8 hours.
The G6 uses a Bluetooth transmitter that is inserted on top of the sensor to transmit data to your phone every 5 minutes. It has a sensor memory of 3 hours (which can be an issue for those with overnight Airplane Mode preferences). No scanning necessary.
Replacement Frequency
The Libre must be replaced every 14 days. The G6 must be replaced every 10 days; it’s transmitter needs to be replaced every 90 days.
Accuracy
Though both are very accurate, the Libre has an overall MARD score of 9.4% while the G6 has an overall MARD score of 9%. The lower the MARD score, the better. In my personal experience with both, the Libre tends to run a bit lower and the G6 a bit higher. For non-diabetics, though, this shouldn’t be an issue.
Calibration
The Libre app will not let you calibrate your sensor. It’s supposed to be calibrated from the factory and will auto-calibrate to your body within the first 24–48 hours. The G6 will let you calibrate your sensor with a finger stick. However, the sensor code that comes with the sensor is Dexcom’s way of calibrating. If you lose the code, you can calibrate your sensor with 2 finger sticks.
The Apps
FreeStyle Libre Link
The Libre app is surprisingly useful on its own. It’s packed full of reports for daily patterns, time in range, low glucose events, average glucose, and sensor usage stats (see below). It even has a logbook and very basic way to log food, exercise, calibration with finger stick (and insulin logging, but not relevant to us non-diabetics).
Using LibreView inside of the Link app, you can connect your data to an external health practice. VERY helpful!
Works equally well on both iOS and Android!
Dexcom G6 App
In contrast to the Libre app the G6 app is quite bare bones. While there is a chart to show your glucose, there’s not a lot else in terms of data. HOWEVER, Dexcom has a separate app for this called Dexcom Clarity, available on iOS, Android, and the web! We’ll go over that in a bit. The G6 App does, of course, have a way to calibrate the sensor. It also has a similar way to add a log — called an “event” for carbs, exercise, health, and insulin. This is the most basic of logging functionality.
Other less-notable features are “share” (to share your data with a “follower” via email) and adding a dependent account (which is helpful if you have dependents who are also using a G6.
Let’s talk about alerts. Do you want alerts?! Do you want them at ALL hours of the night as LOUD AS HUMANLY POSSIBLE?! Look no further than the G6 app! In Dexcom’s defense, they have built this app specifically for diabetics and these alerts are life-saving, so please understand that I say this only in jest. But for the love of all that is holy, please make sure to tweak those alert settings before your first night with this sensor.
Fun fact: the G6 app has an Apple Watch app and complication. However, it is only updated every 15 mins or so or until you tap on the complication or open the watch app.
The G6 app also works equally well on both iOS and Android!
Dexcom Clarity App
I’m sure Dexcom probably make this app separately for many reasons, but I don’t enjoy having to install another app on my phone. Transparently, I have mostly used the web version of Clarity as I find it easier to sift through data on a larger screen. In addition, the mobile app lacks a lot of functionality. Below are some screenshots of the web version functionality.
Conclusion
For a non-diabetic, both of these sensors are great. The Libre is usually cheaper, easier to apply, and more of a 1-step system, but you do have to remember to scan it at least every 8 hours. The G6 is more complicated and more expensive, but you get real-time updates on your glucose. My biggest complaint was the the size of the G6. On my small arms, it felt like a full on medical device, while the Libre was barely noticeable. I also noticed my skin having a reaction to the adhesive on the G6. This hadn’t happened with the Libre, but I do have rather sensitive skin.
For a beginner, I would recommend the Libre. If you’re feeling adventurous and/or don’t feel like manually scanning your sensor, go with the G6. You really can’t go wrong with either.
If you’re curious about a few of the companies with apps that work with the Libre and Dexcom sensors, I wrote an article about them, and I plan on writing about several more in the future, so stay tuned!
