Dexcom G7 vs. FreeStyle Libre 3: A CGM Teardown

2025-03-16 | By bekathwia

Today we’re taking a look inside the two most popular continuous glucose monitors, or CGMs: The Abbott FreeStyle Libre 3 and the Dexcom 7.

Originally developed for diabetes blood sugar monitoring, CGMs are gaining wider appeal among nondiabetics looking to track their metabolic health. It feels pretty cyborg to wear a biosensor that streams data to my phone over Bluetooth.

Dexcom G7 vs. FreeStyle Libre 3: A CGM Teardown

The Dexcom applicator has a button on the side that releases a spring-loaded mechanism. The FreeStyle Libre also has a spring-loaded system, but it’s deployed by pushing down on the whole applicator. It inserts a tiny filament into your skin and sticks the circuit on top. The Dexcom sensor lasts ten days, and the FreeStyle Libre lasts fourteen. Folks often wear an overpatch to help protect the device adhesive, so it doesn’t fall off early.

I sent two of each sensor, unused of course, to my friends at Lumafield, to be CT scanned. One is deployed and the other isn’t, so we can compare and learn more about how the applicator mechanism works.

After their scans, I took both devices apart to check out the inside. The Dexcom unit seemed to have an over-molded shell– the plastic was pretty difficult to remove and covered the entire circuit board.

Dexcom G7 vs. FreeStyle Libre 3: A CGM Teardown

The FreeStyle Libre CGM came apart a little more easily and appears to be a two-part enclosure that is joined together after sandwiching the circuit board inside.

Dexcom G7 vs. FreeStyle Libre 3: A CGM Teardown

My channel’s favorite electrical engineer, David Cranor, joined me to analyze the design and manufacturing of these boards. Watch the video to hear more about what we found!

Dexcom G7 vs. FreeStyle Libre 3: A CGM Teardown