If you're currently wondering whether the Libre 2 or Libre 3 is right for you, or just want to understand how the flash glucose monitoring system actually works: here is my honest review. I'm Sonja from Zuckerschmuck and I've been using the Freestyle Libre since its market launch in Germany in November 2015 — across Libre 1, Libre 2, and with a test phase for Libre 3. This very experience was, by the way, the impetus to found Zuckerschmuck in the first place.
At a glance: Libre 2 vs. Libre 3 (Spec Sheet)
What the manufacturer's data sheets say, soberly side by side [3]:
| Feature | Freestyle Libre 2 | Freestyle Libre 3 |
|---|---|---|
| Sensor Size | approx. 2-euro coin | approx. 5-cent coin (around 60% smaller) |
| Retrieve Values | Scan with reader or app | Live streaming (app, every minute) |
| Reader Device | included in set or separately | not mandatory, smartphone sufficient |
| Bluetooth Alarms | yes | yes, continuous |
| Measurement Interval | 1 min (with scan), 8 h memory | every minute, automatically |
| Wear Time per Sensor | 14 days | 14 days |
| Warm-up Time | 60 minutes | 60 minutes |
| Water Resistance | 1 m / 30 minutes | 1 m / 30 minutes |
| Smartphone Apps | iOS + Android (FreeStyle LibreLink) | iOS + Android (FreeStyle Libre 3 App) |
| Data Sharing with Followers | via LibreLinkUp | via LibreLinkUp |
| Minimum Age Approval | 4 years | 4 years |
| Accuracy (MARD, manufacturer's specification) | approx. 9.2 % | approx. 7.9 % |
From my perspective: anyone who doesn't want to be tied to a smartphone is still well served by the Libre 2 — it has its own reader as a backup, in case the phone is off. Anyone who always has their smartphone at hand will noticeably benefit from Libre 3 live streaming, especially at night with alarms.
How does the Freestyle Libre system work at all?
The Libre is a flash glucose monitoring system (= sensor that continuously measures glucose values in the subcutaneous adipose tissue and transmits them to the end device either via scan or live Bluetooth). Where you used to only get a snapshot with a finger prick, with Libre you see the complete trend — with a trend arrow, an 8-hour graph, and daily patterns.
The method is recognized by the German Diabetes Association in its 2024 practice recommendations as evidence-based therapy support [1] and was already positively evaluated by IQWiG in 2015 as a health insurance benefit [2]. This gives you a more complete picture of your glucose trends and allows you to better assess the effects of meals, exercise, or insulin bolus. How you work with the data and what therapy adjustments make sense is up to your diabetology practice — the sensor does not replace medical advice.
Where can I place the Libre sensor?
The officially approved placement site for the Freestyle Libre 2 and 3 is the back of the upper arm, with sufficient subcutaneous fatty tissue and no folds or pressure points [3]. The sensor is inserted with an applicator that places a small, approximately 5 mm long, flexible filament under the skin — most "diabuddies" find this pain-free.
In practice, many also wear the sensor on their abdomen, thigh, or buttocks. This is "off-label" but works reliably for many if the area has enough fat padding. I now almost exclusively wear the sensor on my upper arm — it stays in place best for me there and causes the least disturbance. If your sensor doesn't adhere well in some places, a Tapeguard adhesive aid can stabilize the adhesive surface without shifting the sensor filament.
Do I need a reader for the Libre 3?
In short: no. With the Freestyle Libre 3, a compatible smartphone with the FreeStyle Libre 3 app is sufficient; everything then runs live via Bluetooth. With the Libre 2, you have a choice — a standalone reader, the app, or both in parallel. If you don't always have your smartphone with you (sports, school, work without a phone), the reader on the Libre 2 is a clear advantage.
For the reader bag or screen protector, we have suitable accessories.
What I've really noticed after several years with Libre
The first hour after placement is critical. Freshly placed sensors undergo a 60-minute warm-up phase, and some even need up to 24 hours to deliver reliable readings. I therefore never plan sensor changes for a day with important meals or exercise.
Readings lag behind blood glucose. The sensor measures interstitial glucose, not direct blood. With rapid changes (exercise, sweets, insulin bolus), the app values are 5–15 minutes behind the actual blood glucose. When correcting a hypo, observe the trend arrow, not just the number. In my self-test Libre 1 vs. Libre 2 vs. blood glucose, I measured in parallel — the agreement is usually good, but not always.
Adhesive allergy can occur. For many "diabuddies," a reaction to the adhesive develops after several sensor changes. What helps me and most customers is described in the FAQ below — and in more detail in Help with Skin Irritation from Sensors.
Waterproof yes, sauna no. Both sensors withstand showering, bathing, and swimming without problems. Sauna is officially not approved — I have still experienced sensors surviving it, but the Bluetooth connection usually breaks in the sauna.
If you want to personalize your Libre
The Libre 3 is small and inconspicuous — but many "diabuddies" deliberately wear it visibly or decorate it with stickers. If you want to show off your sensor, the sensor stickers for the Libre 3 turn the gray plastic part into a small work of art. If you prefer to discreetly camouflage it, we have decorative tapes for the Libre 3 with cut-outs — the same concept is also available for the older Libre 1 + 2 as stickers and as decorative tape.
For a secure fit on the upper arm, there are elastic sensor holders with armbands for the Libre 3 or the matching sensor holder set for Libre 1 + 2.
How do you get the Freestyle Libre?
You can only get the Libre 2 and Libre 3 via Abbott or authorized pharmacies — with a medical indication, health insurance usually covers the system, which IQWiG already evaluated as beneficial in 2015 [2]. At Zuckerschmuck, you'll find the surrounding accessories: decorative tapes, sensor stickers, reader bags, and sensor holders with armbands.
Frequently asked questions about the Freestyle Libre 2 and 3
What is the difference between Freestyle Libre 2 and Libre 3?
The main difference: Libre 2 is read by scanning (with a reader or app), Libre 3 streams the values live to your smartphone every minute — no scanning needed. The Libre 3 sensor is also about 60% smaller and has slightly better accuracy (MARD approx. 7.9% vs. 9.2% for Libre 2 [3]). For me, switching to Libre 3 made a noticeable difference, especially at night — alarms for hypo without me actively having to scan. Complete comparison table: see above.
Do I necessarily need a smartphone for the Libre 3?
Practically yes — the FreeStyle Libre 3 app is the standard receiver. While there is an optional reader device, most "diabuddies" use their phone. With the Libre 2, you still have the choice: reader, app, or both. If you rarely have your smartphone with you, Libre 2 with its own reader is the more solid choice.
Where can I place the Libre sensor?
The officially approved site is the back of the upper arm [3]. Off-label, many "diabuddies" wear the sensor on their abdomen, thigh, or upper buttocks area — this is based on experience, not manufacturer recommendation. What's important is sufficient subcutaneous fat tissue and no folds at the adhesive site. I myself almost exclusively wear the Libre on my upper arm.
What to do for adhesive allergy under the Libre?
If the skin under the sensor itches or is red, skin barrier wipes (e.g., SKIN PREP, SECURA) help as an invisible barrier between the adhesive and the skin. I have detailed instructions with all tricks in the article Help with Skin Irritation from Sensors. In the shop, you'll find the material in the skin protection category.
What accessories are compatible with the Libre 3?
Four accessory categories cover most everyday questions: decorative tapes with cut-outs (camouflage or decorate), sensor stickers (decals for the sensor top), reader bag (for receiver and accessories), and sensor holders with armbands (for secure hold on the upper arm).
Can I swim or shower with the Libre?
Yes. Both sensors are waterproof according to the manufacturer, up to 1 meter deep and for 30 minutes of submersion [3]. Showering, bathing, and swimming are no problem. Sauna is officially not approved — the heat can damage the sensor, and the Bluetooth connection usually breaks for me in the sauna anyway.
What other "Diabuddies" say about Libre accessories
Our customers' reviews show similar patterns to my own experience. Several report that the tapes prevent the sensor from falling off during sports or at work. Others write that before buying, they didn't even know that stickers for CGM sensors existed and are happy to show off the sensor now instead of hiding it. You can see current reviews live in the Judge.me widget on the respective product page.
Sources and Notes
I've linked a few sources below if you want to delve deeper — there's not much more evidence anyway, most of it is manufacturer data and medical therapy recommendations.
- Freckmann G, Eichenlaub M, Pleus S, et al. Glukosemessung und -kontrolle bei Patienten mit Typ-1- oder Typ-2-Diabetes. Diabetologie und Stoffwechsel 2024;19(S 02). Praxisempfehlungen der Deutschen Diabetes Gesellschaft. Available at: DDG Practice Recommendations 2024 (PDF).
- Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen (IQWiG). Kontinuierliche interstitielle Glukosemessung (CGM) mit Real-Time-Messgeräten bei insulinpflichtigem Diabetes mellitus. Abschlussbericht D12-01. Cologne: IQWiG; 2015. Available at: iqwig.de/projekte/d12-01.
- Abbott Diabetes Care. FreeStyle Libre 2 and 3 — Product information and technical specifications. Abbott Germany. Available at: freestyle.abbott/de-de.
Note: This article does not replace medical advice. For questions about therapy, sensor settings, or persistent skin irritations, please contact your diabetology practice. In medical emergencies: call 112.
Best regards, your Sonja
