What is a normal HbA1c level?

Most laboratories report < 5.7 % as normal. Below 5.7% normal, 5.7–6.4% prediabetes, 6.5% or above diabetes.

How do I lower my HbA1c?

Walk for 10–15 minutes after meals. Post-meal movement blunts the glucose excursion more reliably than almost any other single habit. Build resistance training — muscle is the largest glucose sink in the body. Reduce refined carbohydrate, particularly liquid sugar. Improve sleep. A week of short sleep measurably worsens insulin sensitivity in healthy people. Retest no sooner than 12 weeks — the marker cannot move faster than red cells turn over.

Metabolic · Reference range

HbA1c

Q: What is an optimal HbA1c level?

4.8–5.4 %. Observational risk for cardiovascular events and all-cause mortality is lowest in roughly the 5.0–5.4% band, above the level seen in anaemia and below the prediabetic range.

Also reported as: Glycated haemoglobin · A1c · Haemoglobin A1c

The proportion of haemoglobin that has become glycated — a weighted average of blood glucose over the preceding 8–12 weeks.

Lab reference range

< 5.7 %

Below 5.7% normal, 5.7–6.4% prediabetes, 6.5% or above diabetes.

Optimal target

4.8–5.4 %

Observational risk for cardiovascular events and all-cause mortality is lowest in roughly the 5.0–5.4% band, above the level seen in anaemia and below the prediabetic range.

Guideline thresholds from: American Diabetes Association Standards of Care

To convert to mmol/mol, multiply by 10.929.

Check your result

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Your HbA1c (%)

Where the thresholds sit

Band	Range (%)	Note
Low	< 4.8	Can reflect anaemia or shortened red-cell lifespan rather than good glucose control.
Optimal	4.8–5.4	—
Normal	5.4–5.7	—
Prediabetes	5.7–6.5	—
Diabetes range	> 6.5	—

Why it matters

The standard measure of chronic glucose exposure, and the one glycaemic number with hard outcome data behind its thresholds. Its value for healthspan is that it integrates over months, so it cannot be gamed by a good day.

What raises it

Chronic carbohydrate excess relative to activity
Insulin resistance
Iron deficiency anaemia — falsely raises HbA1c
Prolonged red-cell survival, such as after splenectomy

What lowers it

Any intervention that lowers average glucose
Haemolysis, blood loss and recent transfusion — falsely lowers HbA1c
Pregnancy

How to move it

1Walk for 10–15 minutes after meals. Post-meal movement blunts the glucose excursion more reliably than almost any other single habit.
2Build resistance training — muscle is the largest glucose sink in the body.
3Reduce refined carbohydrate, particularly liquid sugar.
4Improve sleep. A week of short sleep measurably worsens insulin sensitivity in healthy people.
5Retest no sooner than 12 weeks — the marker cannot move faster than red cells turn over.

What moves this marker

Interventions on this site with evidence behind them for this specific marker. None of them replaces working out why yours is where it is.

BerberineGrade B

500 mg three times daily with meals

Creatine MonohydrateGrade A

5 g daily

Glucose Control

Protocol · 6 weeks

Muscle Preservation 50+

Protocol · 16 weeks

What makes a single reading misleading

Unreliable in anaemia, haemoglobinopathies (including sickle-cell trait), recent transfusion, pregnancy and chronic kidney disease.
A normal HbA1c can mask large post-meal spikes. Fasting insulin or a CGM shows what it hides.
Ethnic differences in glycation mean the same average glucose can produce slightly different HbA1c values.