CGM Comparison: FreeStyle Libre 3 Plus vs. Dexcom G7 — A Pharmacist's Guide

Dai Tran, PharmD, MBA, B.S.

CEO & Lead Pharmacist, Khang Pharmacy • CA/MN/TX Licensed Pharmacist

Clinical Insights Series • APhA Immunization Certified • 10+ Years Clinical Experience

The CGM Revolution: Why Glucose Monitoring Has Changed Forever

Continuous glucose monitors (CGMs) have fundamentally transformed diabetes management. Where patients once relied on 3–4 painful fingerstick tests per day to get a snapshot of their glucose, today's CGMs deliver real-time readings every 1–5 minutes — automatically, wirelessly, and without a single fingerstick. The result: better glucose control, fewer hypoglycemic episodes, and a dramatically improved quality of life.

Two devices dominate the CGM market in 2025: the FreeStyle Libre 3 Plus by Abbott and the Dexcom G7 by Dexcom. Both are FDA-cleared, covered by Medicare and most insurance plans, and represent the current gold standard in continuous glucose monitoring. But they are meaningfully different devices — and choosing the right one depends on your insulin regimen, lifestyle, and health goals.

As pharmacists who dispense and counsel patients on both devices daily, here is our honest, clinical comparison.

Side-by-Side Specifications

Accuracy: Which CGM Is More Accurate?

Both devices are factory-calibrated and require no fingerstick calibration. Accuracy is measured by Mean Absolute Relative Difference (MARD) — a lower percentage means more accurate readings.

• FreeStyle Libre 3 Plus: 7.9% MARD — clinically excellent accuracy, slightly better than the G7 overall
• Dexcom G7: 8.2% overall MARD — with notably strong accuracy in the hypoglycemic range (below 70 mg/dL), which is critical for insulin-dependent patients

Pharmacist note: For most patients, the accuracy difference between these two devices is clinically insignificant. Both are accurate enough to make treatment decisions without confirmatory fingersticks in most situations. The Dexcom G7's edge in the low glucose range makes it the preferred choice for patients on insulin who are at higher risk of hypoglycemia.

Sensor Wear & Convenience

FreeStyle Libre 3 Plus — 15-Day Wear

The Libre 3 Plus wins on sensor longevity — 15 days per sensor means fewer sensor changes per month (approximately 2 per month vs. 3 for the G7). The sensor is also the world's smallest and thinnest CGM sensor, making it exceptionally discreet. Many patients — particularly those new to CGM — prefer the Libre 3 Plus for its low profile and ease of use.

Dexcom G7 — 10-Day Wear + 12-Hour Grace Period

The G7 offers a 12-hour grace period after the 10-day wear period, giving patients flexibility if they cannot change the sensor immediately. The G7's all-in-one sensor/transmitter design (no separate transmitter to charge) simplifies the user experience considerably compared to older Dexcom models.

Insulin Pump Integration: The Decisive Factor

This is where the two devices diverge most significantly — and where the right choice becomes clear for many patients.

The Dexcom G7 integrates directly via Bluetooth with the Omnipod 5 and Tandem t:slim X2 insulin pumps, enabling fully automated closed-loop insulin delivery (also called an artificial pancreas system). The pump reads the G7's glucose data every 5 minutes and automatically adjusts basal insulin — increasing, decreasing, or suspending delivery — without any patient input.

The FreeStyle Libre 3 Plus does not currently integrate with any insulin pump for automated delivery. It is a standalone CGM.

Bottom line: If you use or are considering an insulin pump — particularly the Omnipod 5 — the Dexcom G7 is the required CGM. If you manage diabetes with oral medications, GLP-1 agonists, or basal insulin only, the Libre 3 Plus is an excellent and more affordable choice.

Alerts & Alarms

Both devices offer customizable high and low glucose alerts. The Dexcom G7 has one notable advantage: the Urgent Low Soon alert, which warns patients up to 20 minutes before a predicted severe hypoglycemic event. For insulin-dependent patients — particularly those with hypoglycemia unawareness — this predictive alert can be life-saving.

The FreeStyle Libre 3 Plus offers real-time high and low alarms but does not include a predictive low alert.

Insurance Coverage & Cost

Both devices are covered by Medicare Part B, Medi-Cal, and most private insurance plans for patients with diabetes who meet clinical criteria. Many patients pay $0/month with Medicare or Medi-Cal coverage.

• Medicare Part B: Covers CGMs as durable medical equipment (DME) for patients with diabetes who are treated with insulin or have a history of problematic hypoglycemia
• Medi-Cal: Covers both devices for eligible patients — contact our pharmacy team to verify your specific plan
• Private insurance: Coverage varies by plan; prior authorization is often required
• Cash pay: The FreeStyle Libre 3 Plus is generally less expensive per sensor than the Dexcom G7 for patients paying out of pocket

Our pharmacists handle the full insurance coordination process — prescription verification, prior authorization, and insurance billing — so you receive your CGM with minimal hassle. Call us at (408) 622-8068.

Who Should Choose the FreeStyle Libre 3 Plus?

• 🟢 Type 2 diabetes patients on oral medications, GLP-1 agonists, or basal insulin only
• 🟢 Patients new to CGM who want an easy, discreet, low-maintenance device
• 🟢 Patients prioritizing sensor longevity — 15-day wear means fewer changes
• 🟢 Cost-conscious patients paying out of pocket — lower per-sensor cost
• 🟢 Patients wanting maximum caregiver sharing — up to 20 followers via LibreLinkUp
• 🟡 Patients on multiple daily injections (MDI) — excellent choice, though no predictive low alert

Who Should Choose the Dexcom G7?

• 🟢 Patients using or considering the Omnipod 5 or t:slim X2 insulin pump — G7 integration is required for automated insulin delivery
• 🟢 Patients with hypoglycemia unawareness — the Urgent Low Soon alert provides critical advance warning
• 🟢 Patients on multiple daily injections (MDI) with frequent lows — superior low-range accuracy and predictive alerts
• 🟢 Apple Watch users — native glucose display on Apple Watch
• 🟢 Patients wanting the fastest sensor warm-up — 30 minutes vs. 60 minutes for Libre 3 Plus
• 🟡 Patients on Medicare — both are covered; discuss with your pharmacist which is preferred by your plan

What About Traditional Test Strips?

Even patients using a CGM benefit from keeping FreeStyle Lite Test Strips on hand. Test strips are essential during CGM sensor warm-up periods (30–60 minutes), when a sensor reading seems inconsistent with symptoms, or as a backup if a sensor fails. Our pharmacists recommend keeping a box of test strips available regardless of which CGM you use.

Pharmacist's Bottom Line

Choose the FreeStyle Libre 3 Plus if you want a discreet, easy-to-use CGM with 15-day wear and do not use an insulin pump. It is the best entry point into continuous glucose monitoring for most Type 2 diabetes patients.

Choose the Dexcom G7 if you use or plan to use the Omnipod 5 or t:slim X2 insulin pump, have hypoglycemia unawareness, or want the fastest warm-up time and predictive low alerts.

Both devices represent a transformational improvement over fingerstick testing. The best CGM is the one you will actually wear consistently — and our pharmacists are here to help you make that decision with confidence.

Call us at (408) 622-8068 or stop by to discuss which CGM is right for you, verify your insurance coverage, and get started.

Frequently Asked Questions

Q: Do I need a prescription for a CGM?
A: Yes. Both the FreeStyle Libre 3 Plus and Dexcom G7 require a prescription. Our pharmacists can coordinate with your prescriber to obtain the prescription and process your insurance.

Q: Can I switch from Libre to Dexcom (or vice versa)?
A: Yes. A new prescription is required for the different device. Contact our pharmacy team and we will handle the transition, including insurance reauthorization.

Q: Does Medicare cover CGMs?
A: Yes. Medicare Part B covers CGMs as durable medical equipment for eligible patients with diabetes. Most patients pay $0 after Medicare coverage. Contact us to verify your eligibility.

Q: Can I use the FreeStyle Libre 3 Plus with the Omnipod 5?
A: No. The Omnipod 5 automated insulin delivery system requires the Dexcom G7 for closed-loop functionality. The Libre 3 Plus is not compatible with any current insulin pump for automated delivery.

Q: How do I get started?
A: Call Khang Pharmacy at (408) 622-8068 or stop by. Our pharmacists will verify your insurance, obtain your prescription, and provide hands-on training for your new CGM device.

Shop Diabetic Supplies at Khang Pharmacy

• FreeStyle Libre 3 Plus Continuous Glucose Monitor System →
• Dexcom G7 Continuous Glucose Monitor System →
• Omnipod 5 Automated Insulin Delivery System →
• FreeStyle Lite Blood Glucose Test Strips (100 Count) →

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Reviewed by

Dai Tran, PharmD, MBA • View full bio →

CEO & Lead Pharmacist, Khang Pharmacy • CA/MN/TX Licensed • 10+ Years Clinical Experience

Disclaimer: This article is written for educational purposes by the Khang Pharmacy PharmD team. It is not intended as medical advice and does not replace consultation with your healthcare provider. Individual device suitability depends on your full health history, insulin regimen, and insurance coverage. Always consult a pharmacist or physician before starting any new medical device or therapy.

Khang Pharmacy | 2451 S King Rd., Ste A1, San Jose, CA 95122 | (408) 622-8068 | www.khangpharmacy.com