What are normal glucose levels for a non-diabetic man using a CGM?

For a metabolically healthy non-diabetic man, the cardiologist-endorsed CGM targets are: fasting glucose 70–90 mg/dL, post-meal peak below 140 mg/dL returning to baseline within two hours, and time in range (70–140 mg/dL) above 90% over a 14-day wear period. These are tighter than the diabetes diagnostic thresholds deliberately.

The diabetes diagnosis threshold of 126 mg/dL fasting or 200 mg/dL post-meal reflects where disease is confirmed, not where ideal metabolic function lives. Levels Health's research documented that 40% of individuals classified as having normal fasting glucose would be reclassified as pre-diabetic based on sequential CGM data. That gap, between "not diabetic" and "metabolically best", is exactly what CGM helps you see. (Dunn et al., PLOS Biology, 2018)

Cardiologist's calibrated position, Solid (1) for the 140 mg/dL post-meal threshold. This is the level above which endothelial oxidative stress begins to accelerate meaningfully in prospective studies. Below this, you are in territory where CGM data does not carry a strong cardiac signal. Above it repeatedly, you have a real finding worth addressing.

What to do: Focus on your post-meal peak and return-to-baseline time rather than the raw number. A peak of 132 mg/dL that returns to 82 mg/dL in 90 minutes is a healthy pattern. A peak of 128 mg/dL that stays elevated at 115 mg/dL three hours later is a metabolic efficiency problem worth addressing.

For the full picture, read The CGM on Your Arm Doesn't Know Your Arteries.