Optimal Ranges
What is the optimal range for HbA1c?
Clinical (NHS) Range
20-42 mmol/mol (below 6.0%)
mmol/mol
Performance-Optimised Range
20-34 mmol/mol (below 5.4%)
mmol/mol
| Range | Value | Unit |
|---|---|---|
| Clinical (NHS) reference range | 20-42 mmol/mol (below 6.0%) | mmol/mol |
| Performance-optimised range | 20-34 mmol/mol (below 5.4%) | mmol/mol |
The clinical range defines what is considered medically “normal” — broad enough to cover 95% of the population. The performance range reflects where research and clinical experience suggest most people feel and function at their best. A result in either range suggests typical status and is not a diagnosis; any individual reading should be interpreted by a qualified clinician.
Why It Matters
Why HbA1c matters for performance
Metabolic health is the foundation of performance. Elevated HbA1c — even within the pre-diabetic range — is associated with increased body fat storage, reduced energy, impaired recovery, and accelerated ageing. Many men who appear healthy and train regularly still have elevated HbA1c due to chronic stress, poor sleep, or high-carbohydrate diets. Catching metabolic dysfunction early provides a window to reverse it through lifestyle interventions before it becomes clinical diabetes.
Symptoms
What are the symptoms of low or high HbA1c?
Low / Deficiency
- Not applicable — low HbA1c is generally favourable
- Extremely low may indicate hypoglycaemia or blood disorders
High / Excess
- Increased thirst and frequent urination
- Persistent fatigue after meals
- Difficulty losing body fat
- Slow wound healing
- Brain fog and poor concentration
- Blurred vision
Dietary Sources
Which foods support HbA1c levels?
Supplementation
How do you improve HbA1c levels?
Berberine (500 mg 2-3x daily with meals) has robust evidence for improving insulin sensitivity, comparable to metformin in some studies. Chromium picolinate (200-1,000 mcg/day) may support glucose metabolism. Alpha-lipoic acid (300-600 mg/day) is an antioxidant that aids glucose uptake. However, the primary interventions for HbA1c are dietary — reducing refined carbohydrates, time-restricted eating, and post-meal walking.
Testing
How is HbA1c tested in the UK?
HbA1c is measured from a blood sample. With Helvy, that means a finger-prick kit taken at home and posted to a UKAS-accredited UK laboratory, with results in around 5 days, reviewed by a qualified clinician. Your result is reported against both the clinical range (20-42 mmol/mol (below 6.0%)) and the performance-optimal range (20-34 mmol/mol (below 5.4%)), so you can see not just whether you are “normal” but whether you are optimal. If you make a change, retest after 8-12 weeks to confirm it worked.
Research
Key study
Efficacy of berberine in patients with type 2 diabetes mellitus
Yin J, Xing H, Ye J
Metabolism (2008)
DOI: 10.1016/j.metabol.2008.01.013Related Biomarkers
Related Guides
Explore HbA1c in depth
Test your HbA1c levels
HbA1c is included in the Helvy 50+ biomarker panel. Get your results in 5 days with a personalised protocol.
Order Your TestThis content is for educational purposes only and does not constitute medical advice. Your data suggests areas for optimisation, but any concerns should be discussed with a qualified healthcare professional. If your results flag values outside safe ranges, we recommend consulting your GP.