HbA1c is your 90-day average glucose — and one of the most commonly misread results in standard medicine. 'Normal' is not the same as optimal.
The Stack Analyzer maps your goals and current data to the right measurement path, protocol, and stack — in order.
Hemoglobin A1c (HbA1c) measures the percentage of hemoglobin proteins in your red blood cells that have glucose attached to them — a process called glycation. Because red blood cells live approximately 90–120 days, HbA1c reflects average blood glucose over that window. It is not affected by what you ate the day before the test.
Standard US reference ranges flag HbA1c as normal up to 5.7%. Research shows that metabolic risk begins accumulating well below this threshold — and that HbA1c under 5.3% is associated with substantially lower cardiovascular and cognitive risk.[1] The gap between 5.3% and 5.6% is clinically meaningful and largely ignored by standard care.
Percentage (%)
Under 5.3%
Under 5.7% — acceptable but not optimal
5.7–6.4%
Every 90 days if above 5.3% and actively intervening
| HbA1c | Classification | CreusLife Target? |
|---|---|---|
| Under 5.1% | Optimal | ✓ Ideal target |
| 5.1–5.3% | Good | ✓ Acceptable |
| 5.3–5.7% | Standard normal — suboptimal for optimization | Aim lower |
| 5.7–6.4% | Pre-diabetes | Clinical conversation warranted |
| 6.5%+ | Type 2 diabetes threshold | Requires physician management |
Reference ranges vary by lab, age, sex, medication status, and clinical context. Use these as discussion prompts with your clinician — not as diagnosis.
HbA1c and fasting insulin together give a complete metabolic picture. HbA1c reflects average glucose; fasting insulin reveals the compensatory effort required to achieve it. Both can be ordered through Quest or a comprehensive testing platform.
For cardiometabolic risk, the highest-value home measurements are blood pressure, glucose response, and rhythm awareness.
The Stack Analyzer uses your measurements to build a personalized protocol, supplement stack, and 30-day plan.