What is an optimal HbA1c level?
The short answer
An optimal HbA1c level is 4–5.4 %. Dr. Rangan Chatterjee puts the ceiling at 5.4. You can watch him say it below.
“if certain blood biomarkers are in the normal range, so a fasting insulin under six, an HbA1c maybe under 5.4, even under 5.2, a good triglyceride to HDL ratio, so under 1.5 — then in some ways the debate over the diet is semi-pointless.”
Where a number lands, and who said so
- under 4 % Most labs flag this as low
- 4–5.4 % The range Dr. Rangan Chatterjee draws
- 5.4–5.7 % Normal on most reports. Above optimal Dr. Rangan Chatterjee · 1:52:27 →
- over 5.7 % Most labs flag this as high
What HbA1c measures
The share of your haemoglobin with sugar stuck to it. That builds up over the life of a red blood cell.
It averages your blood sugar over the past few months. One good day or one bad day leaves it where it is.
Checked against MedlinePlus — Hemoglobin A1C (HbA1c) Test.
One of the doctors we cite, on why it matters
“the papers that have reported hemoglobin A1C of less than five is associated with less diabetes and disorders of chronic disease that you just talked about. So as hemoglobin A1C creeps up by a tenth of a point that changes dramatic and your risk of disease as you age goes up with each tenth of a point.”
Common questions
What is an optimal HbA1c level?
4–5.4 %, according to Dr. Rangan Chatterjee.
What is a normal HbA1c level?
Most US labs print 4–5.7 %. Your report grades you against that range. It exists to catch disease, not to describe your best.
What does your HbA1c number mean?
Under 4 %, your report marks it low. Between 4 and 5.7 it prints as normal. Over 5.7, your report marks it high. Where the people we follow draw their own line is above.
Do they all agree?
No. Dr. Mark Hyman puts the line somewhere else: “six is sort of the cut off, five and a half is really optimal.”
What does the HbA1c test measure?
The share of your haemoglobin with sugar stuck to it. That builds up over the life of a red blood cell. It averages your blood sugar over the past few months. One good day or one bad day leaves it where it is.
Where does this number come from?
Dr. Rangan Chatterjee, on video. The link above jumps straight to that minute.
They don't all draw the line in the same place
“six is sort of the cut off, five and a half is really optimal.”