Continuous Glucose Monitoring (CGM)
Continuous Glucose Monitoring (CGM) provides real-time blood sugar readings through a sensor that works around the clock. This technology greatly reduces the need for fingerstick tests while giving users valuable insights into glucose trends and fluctuations throughout the day and night.
This content is not medical advice. Always consult your endocrinologist, doctor or diabetes care team before making any changes to your diabetes treatment or daily management.
What is Continuous Glucose Monitoring (CGM)?
Continuous Glucose Monitoring (CGM) is a technology that measures glucose levels under the skin at regular intervals—usually every few minutes. Instead of relying only on occasional fingerstick checks, CGM provides a steady stream of information about glucose values and their direction of change. This helps people with diabetes understand not only their current level but also whether it is rising, falling, or staying steady. Unlike fingerstick testing that measures blood glucose directly, CGM sensors track glucose in the interstitial fluid (the fluid surrounding the body’s cells). Because of this, readings may lag a few minutes behind blood glucose, especially when levels are changing quickly, but they still provide highly valuable insights for daily management.
Who Can Use CGM?
People with Type 1 diabetes (especially those on multiple daily injections or insulin pumps).
People with Type 2 diabetes who use insulin or want to better understand glucose patterns.
Pregnant women with gestational diabetes who require close monitoring.
Anyone experiencing frequent hypoglycemia or glucose variability.
How a CGM System Works?
A complete CGM system usually includes three main components:
Sensor – A tiny sensor placed just beneath the skin that continuously measures glucose for a set number of days, depending on the model.
Transmitter – A small device that sits on top of the sensor and wirelessly sends glucose data. Some transmitters are built into the sensor and are disposable, while others can be reused.
Receiver or Smart Device – A phone app, smartwatch, insulin pump, or separate reader that displays glucose numbers, trend arrows, and historical graphs.
Benefits of Using CGM
Lower A1C and better control – Regular use of CGM has been shown to help many people bring their A1C down and keep it stable.
Less time in hypoglycemia – By warning users of dropping glucose before it becomes dangerous, CGM can reduce the time spent in low blood sugar.
Alerts and notifications – Customizable alarms notify users when glucose is heading too high or too low, helping them take action sooner.
Real-time insights – Trend arrows show not just where glucose is now, but where it’s going, giving a clearer picture for decision-making.
Data sharing – Many CGM systems allow sharing information with caregivers, family, or healthcare teams, offering additional safety and support.
While CGM provides major advantages, users should also be aware of certain limitations and practical considerations.
Limitations of CGM
Occasional fingerstick tests may still be required (for calibration or confirmation).
Readings can lag slightly compared to blood glucose, especially during rapid changes.
Sensors need to be replaced regularly (every 7, 10, 14, or up to 90 days depending on the system).
Costs and insurance coverage vary by country and healthcare system.
- Skin irritation or adhesion issues.
DIAMOND Study (Dexcom CGM, Type 1 Diabetes, MDI)
This study showed that participants with a baseline HbA1c ≥ 8.5% experienced an average HbA1c reduction of approximately 1.3% after 24 weeks of CGM use.
CGM Devices / Sensors
Continuous glucose monitoring (CGM) technology is evolving quickly, with new sensors offering longer wear time, improved accuracy, and more comfortable designs. As of 2025, several next-generation devices are available, while others are being rolled out in different regions.
Latest and Notable CGM Systems
Dexcom G7 (15-day version)
– now approved for longer wear, faster warm-up, and advanced integration with pumps and apps.
Dexcom ONE+ – a simplified but modern real-time CGM with alerts, designed for wider access.
Dexcom Stelo – an over-the-counter CGM, primarily for people not using insulin, offering glucose insights without prescription.
Abbott FreeStyle Libre 3 / Libre 3 Plus – compact, real-time sensors with continuous data and longer wear options.
Medtronic Guardian 4 – integrates with automated insulin delivery (AID) pumps, featuring predictive alerts.
Medtronic Simplera Sync – new all-in-one sensor designed for easier insertion and pump connectivity.
Senseonics Eversense E3 / Eversense 365 – implantable CGM lasting up to 6 months (E3) or a full year (365).
Medtrum EasySense / EasyPatch systems – patch-style CGMs with ~14-day wear, depending on the model.
Important Notes on Availability
✅ Varies by country – not all sensors are approved everywhere; some are FDA-cleared in the U.S., others only available in Europe or Asia.
✅ Insurance coverage – access often depends on national health insurance, private insurance, or out-of-pocket purchase.
✅ Prescription vs. OTC – some CGMs (e.g., Dexcom Stelo in the U.S.) are available without prescription, while most others still require one.
✅ Consult your care team – the best CGM for you depends on your type of diabetes, insulin therapy, lifestyle, and local availability.
Continuous glucose monitors (CGM) not only provide real-time glucose insights but are also closely connected with insulin pumps in advanced diabetes management. Many modern pumps can integrate directly with CGM data to automate insulin delivery and improve time in range. To learn more about how insulin pumps work and why they are important alongside CGM, visit our dedicated Insulin Pumps category.
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