Marker · Ranges for learning, not a diagnosis
Fasting glucose
Also called fasting blood sugar, FPG.
Blood sugar in the morning after a night without food. One day, not a three-month average.
Read this first
- Coach, not doctor. Aaron Cuha is a coach, not a doctor. No medical credential is claimed for him, or for these pages. A number on a blood test is something to talk over with a doctor, not something to diagnose yourself with. Nothing here is a prescription, a plan to follow, or a reason to start or stop a medicine. Educational use only. This database summarizes published research and is not medical advice. Where a dose appears it is a record of what a trial or clinic ran, or what people describe doing, with its source attached. Nothing here is a recommendation for personal use.
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Why a longevity audience asks
It is the other half of the owner's berberine trigger, and the number a doctor reads next to A1c. One high morning does not make a diagnosis.
How a coach reads it
Doctors often treat under 100 mg/dL as the usual fasting range, 100 to 125 as raised fasting blood sugar, and 126 and above on more than one day as a sign of diabetes. For learning, not a diagnosis. To turn mmol/L into mg/dL, multiply by 18.
Units on this page: mg/dL, mmol/L
When it is low
Low fasting blood sugar can come from a medicine, a long fast, or something that needs a doctor the same day if you feel unwell.
When it is high
Means your overnight blood sugar sits high. Food, training, sleep, alcohol and medicines move it. A capsule is not the first thing to change.
Easy ways to misread it
- Coffee, a late meal, poor sleep and steroid medicines can push up a single morning.
- If you ate before the blood draw, do not call it a fasting number.
What to ask your doctor
Ask for a true fasting blood sugar, on the same draw as HbA1c. Say what you took that morning.
Related supplements
Related when-playbooks
The ranges on this page are labeled as a doctor's ranges or the owner's. They are not a trial result made up for the page. The related compound pages show the trials.