CGM Myths on a GLP-1, Corrected

A CGM hands you a firehose of data, and without context it's easy to misread. New wearers often panic at numbers that are perfectly normal, or relax about ones worth watching. Here are the misreadings that trip people up most on a GLP-1, and what the evidence actually supports.

Myth: a single low reading means a dangerous hypo

One number below 70 mg/dL is not automatically an emergency. Sensors have a margin of error, they can read low from pressure if you lie on the sensor, and brief dips happen in people without diabetes too. What matters is the pattern: repeated lows, lows with real symptoms, or lows while you're on insulin or a sulfonylurea. For someone taking a GLP-1 on its own, meaningful hypoglycemia is uncommon, because the drug only nudges insulin when glucose is already high (Bergenstal 2026). Treat a lone low as information, not alarm, and watch whether it becomes a trend.

Myth: any post-meal spike is a failure

Glucose is supposed to rise after you eat. A post-meal bump is normal physiology, not a sign something's broken. What's worth attention is how high the peak goes and how long it takes to come back down, not the mere fact of a rise. On a GLP-1, you'll often see those peaks flatten over time, but a visible rise after a big or carb-heavy meal is expected and fine. Chasing a perfectly flat line after every meal is a recipe for anxiety, not health.

Myth: flatter is always better, at any cost

Steadier glucose is a reasonable goal, but "flat at all costs" can push people toward under-eating or cutting out foods they don't need to. The consensus targets are about staying in a healthy range most of the time and keeping variability under control (Battelino 2019), not about erasing every wave. A steady line achieved by barely eating isn't a win. Context beats flatness.

Myth: the CGM number is exact

Consumer CGMs are accurate enough to show trends and patterns, which is what they're for, but they aren't as precise as a lab blood draw. They also read interstitial fluid, which lags blood glucose by several minutes, so a fast change shows up on the sensor a little late. Use the sensor for direction and patterns rather than treating a single decimal as gospel.

Myth: more data means you should react to every wiggle

The value of a CGM is in the trends across days and weeks, not in reacting to every minor movement. Constant micro-adjusting turns a useful tool into a stress machine. Zoom out. Look at your time in range and your variability over a week, and let the small stuff be small.