Continuous Glucose Monitors: A Powerful Tool — When Used Wisely
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Have you ever seen someone wearing a small sensor on their arm and thought, “Should I be using one of those?” You’re not alone.
In this episode of Endocrine Matters, Dr. Arti Thangudu, board-certified endocrinologist and founder of Complete Medicine, dives deep into the pros and cons of continuous glucose monitors (CGMs) like Dexcom and Freestyle Libre.
Spoiler alert: CGMs are powerful tools — but only when used with medical guidance and context.
What Is a CGM?
A continuous glucose monitor is a wearable device that tracks glucose levels in the fluid between your cells. It provides continuous readings sent to your phone or device, offering real-time insight into how your body responds to food, exercise, sleep, and stress.
The two most common CGMs are Dexcom and Freestyle Libre. They’ve transformed diabetes care by making glucose data accessible and actionable — replacing outdated fingersticks with dynamic trend graphs.
Why CGMs Are a Game Changer
For people with type 1 or type 2 diabetes, especially those using insulin, CGMs can be life-saving. They help identify dangerous highs and lows before symptoms appear. For those with prediabetes or insulin resistance, CGMs can illuminate how different foods and habits affect glucose levels — leading to personalized nutrition and lifestyle changes.
But as Dr. Thangudu explains, the power of CGMs lies in the interpretation, not just the data.
The Pitfalls of Using CGMs Without Guidance
With the rise of wellness tech and direct-to-consumer CGMs, many people are using these devices without expert help — and that can backfire.
Some common issues:
Misreading normal glucose changes (e.g., post-meal spikes) as “bad”
Overreacting to false lows, leading to unnecessary sugar intake
Becoming overly restrictive or anxious about food
Driving up A1c levels due to misunderstanding the data
Dr. Thangudu has seen patients go from normal blood sugar to prediabetic ranges because they misunderstood CGM feedback. Data without context can lead to fear — or worse, harm.
Understanding Normal Glucose Responses
Here’s what’s normal:
Glucose rises after eating (especially carbs)
Glucose spikes after intense workouts
Morning glucose may be higher due to cortisol (“dawn phenomenon”)
These aren’t red flags — they’re signs your body is doing its job. That’s why expert interpretation is key.
The Bottom Line: Use CGMs Wisely
CGMs like Dexcom and Freestyle Libre are incredibly useful, especially for people with diabetes, prediabetes, or metabolic health concerns. But they’re not for everyone — and they’re not self-explanatory.
✅ Work with an endocrinologist or trained clinician
✅ Look at patterns, not single numbers
✅ Don’t panic over normal physiology
✅ Confirm odd readings with a fingerstick
✅ Use CGMs for insight, not obsession
When used with care and context, CGMs can help you eat, move, and live better — with confidence.
💡 Ready to explore CGMs with expert support?
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Because data is powerful — but wisdom is what turns it into health.
FAQ: Continuous Glucose Monitors (CGMs)
Do I need a continuous glucose monitor if I don’t have diabetes?
Not necessarily. While CGMs can offer useful insights into how food, stress, and exercise affect glucose levels, they can also cause confusion or anxiety if used without proper guidance. If you’re curious, talk to an endocrinologist about using a CGM short-term as a learning tool rather than a permanent device.
Which CGM is better — Dexcom or Freestyle Libre?
Both Dexcom and Freestyle Libre are accurate, FDA-approved, and effective. Dexcom offers real-time continuous readings and customizable alerts, making it ideal for people who need tight glucose control. Freestyle Libre provides on-demand scans and is often more affordable. The right choice depends on your medical needs and lifestyle.
Are over-the-counter CGMs worth it?
OTC CGMs improve accessibility, but they’re not always cheaper and rarely come with expert interpretation. Before buying one, ask your doctor whether you qualify for a prescription model — and whether a CGM is appropriate for your goals.
Why does my CGM show a “low” when I feel normal?
CGMs measure interstitial fluid, not blood. Readings can lag or be inaccurate, especially during the first 24 hours of wear. Always confirm unexpected highs or lows with a fingerstick. If issues persist, ask your clinician to review your data or troubleshoot your sensor placement.
Is it normal for my glucose to spike after meals or exercise?
Yes. Glucose rises after carbohydrate-containing meals and during or after vigorous exercise. Morning glucose may also be higher due to the dawn phenomenon. These patterns are normal — not signs of dysfunction. Understanding healthy glucose responses is key to using CGMs wisely.
Can using a CGM improve my metabolic health?
Absolutely — when paired with professional guidance. CGMs allow you and your doctor to identify patterns, personalize your nutrition, adjust medications, and build habits that support long-term metabolic health. The device is helpful, but interpretation is everything.