Over-the-Counter Continuous Glucose Monitor (CGM)

A CGM (continuous glucose monitor) is not just for diabetics: it shows you the glucose curve over 14 days after meals, sleep, or exercise, not just an average like HbA1c. The real value is the experiment — you test foods and get a personal map of what affects you. Options: Dexcom Stelo (OTC), FreeStyle Libre 3, Lingo, Sibionics, Dexcom G7. Costs ~250–400 lei/sensor. Do not self-diagnose diabetes and do not panic over false nighttime hypos.

27 October 2026 · 5 min

Why it’s not ‘just for diabetics’

Because it shows you, over 14 days, what no blood test can show: the curve of glucose after you eat, at 3 a.m., after climbing stairs, after a coffee. HbA1c gives you an average over 3 months — a single number, without shape. CGM gives you the movie. And for most people, the movie is surprising: you discover that a ‘healthy breakfast’ of cereal and orange juice peaks at 180 mg/dL, while a lunch of boiled and cooled potatoes (resistant starch) barely moves you.

The practical value is not the number, it is the experiment: wear the sensor for 14 days, test 10–15 foods/meals, and in the end, you have a personal map of what works for you. People lose weight and stabilize their blood sugar more from this than from any generic diet — because ultimately, the glycemic response is individual.

The second benefit, less obvious: sleep. The CGM shows compression "hypos" (the sensor pressed during sleep gives falsely low values — so don’t panic at 3 AM) and, more importantly, the effect of a late dinner or alcohol. For someone who wakes up tired for no reason, it’s a piece of the puzzle.

Options and the differences that matter

Dexcom Stelo — the first OTC CGM, no prescription, 15 days, designed specifically for people without insulin (type 2 diabetes or simply curious). FDA clearance in 2024. It does not give hypoglycemia alarms (this is intentional — for those not taking insulin, alarms do more harm than good).
Abbott FreeStyle Libre 3 / Libre 3 Plus — the smallest sensor, 14–15 days, read directly on your phone without scanning. CE marked, available in Europe, including pharmacies in Romania (sometimes even without a prescription, depending on the pharmacy).
Abbott Lingo — the wellness version, without medical claims: no diagnosis, just "body insights". Cheaper and more user-friendly if you don't have a diagnosis and just want to learn.
Sibionics GS1 — a Chinese manufacturer with CE marking, also 14 days, significantly cheaper. Data quality is decent in studies, but the application ecosystem is weaker. If the budget is tight, it's an honest option.
Dexcom G7 — the most accurate and fastest to calibrate, but designed for insulin-dependent diabetics; in the EU, it requires a prescription.

Costs (estimates, verify)

A 14–15 day sensor: around 250–400 lei in the EU, similar in the USA (~90–100 $ for Stelo, without insurance).
So a one-month "experiment" (2 sensors) costs about as much as a weekend in the mountains. It's not cheap, but it's not absurd either, and it's the best educational investment in nutrition you can make.

What not to do with it

Do not self-diagnose diabetes based on it. A sensor does not replace HbA1c and the oral glucose tolerance test. If you see values of 200+ repeatedly, consult a doctor — the CGM is the reason, not the verdict.
Do not panic at low nighttime values — sensor compression can cause false hypos. Confirm with a finger test if you feel well.
Do not make radical dietary changes in 14 days based on a single sensor. Trends appear on the second wear, when comparing the same meals.
Skin irritation is real; rotate the application site and use a protective adhesive if you have sensitive skin.