Continuous Glucose Monitor (CGM) Protocol — Diagnostics & Biomarker Testing
Real-time interstitial glucose monitoring revealing metabolic responses to food, exercise, sleep, and stress — the most actionable metabolic feedback tool available.
Overview
Continuous glucose monitors (CGMs) — including Dexcom G7, Abbott FreeStyle Libre, and Stelo/Lingo (designed for non-diabetics) — track interstitial glucose every 1-5 minutes, providing a continuous picture of metabolic health that HbA1c and fasting glucose miss entirely. A single HbA1c reflects a 90-day average but hides dangerous glucose spikes. Levels (Levels Health) was the first company to make CGMs accessible to non-diabetics with interpretive software. Jesse Mechauspé (Glucose Goddess), Peter Attia, and Rhonda Patrick have popularized CGM use among healthy individuals for metabolic optimization. Key metrics include time-in-range (70-140 mg/dL), mean glucose, glycemic variability, peak glucose after meals, and post-exercise glucose response. A 2022 Nature Metabolism study (n=4,416 non-diabetics) found that only 12% of Americans have optimal metabolic health — CGM reveals this invisible epidemic.
Indications
- Postprandial glucose spike identification and food response profiling
- Metabolic health baseline and trend monitoring
- Insulin resistance detection before HbA1c elevation
- Exercise impact on glucose (zone 2 fat oxidation confirmation)
- Sleep, stress, and caffeine effect on glucose
- Pre-diabetes and T2D risk stratification
Mechanism of Action
A glucose oxidase enzyme on the sensor filament oxidizes interstitial glucose, producing an electrical current proportional to glucose concentration
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| CGM (Dexcom Stelo, Abbott Lingo) | Continuous wear, 10-14 day sensor | 2-4 week trial or ongoing | Non-prescription CGMs (Stelo, Lingo) available OTC; Dexcom G7 and FreeStyle Libre require Rx in USA |
Evidence Grade
GRADE B
Safety & Contraindications
- Minor skin irritation or allergic reaction to adhesive at sensor site
- Readings lag behind blood glucose by ~5-15 minutes (interstitial fluid delay)
- CGM readings can be inaccurate during rapid glucose change (compression artifact while sleeping)
- Acetaminophen and some other medications interfere with electrochemical glucose sensing (Dexcom-specific)
- Not a substitute for blood glucose meter in insulin-dependent diabetics making dosing decisions