Optimal Ranges
Clinical (NHS) Range
30-400 ng/mL
ng/mL
Performance-Optimised Range
80-150 ng/mL
ng/mL
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.
Why It Matters
Why Ferritin matters for performance
Iron is essential for oxygen transport, energy production, and cognitive function. Low ferritin — even within the 'normal' clinical range — is one of the most underdiagnosed causes of persistent fatigue in active men. Athletes and men who train regularly deplete iron through sweat, foot-strike haemolysis, and increased red blood cell turnover. Ferritin below 50 ng/mL in an active man often correlates with reduced endurance, poor recovery, and unexplained performance plateaus.
Symptoms
Signs your levels may be off
Low / Deficiency
- Persistent fatigue despite adequate sleep
- Breathlessness during training
- Pale skin and dark circles
- Restless legs
- Cold hands and feet
- Reduced training capacity
High / Excess
- Joint pain
- Abdominal pain
- Skin bronzing
- Liver damage (haemochromatosis)
Dietary Sources
Foods that support Ferritin levels
Supplementation
Evidence-based supplementation approach
Iron bisglycinate is the preferred supplemental form due to superior absorption and fewer gastrointestinal side effects. Typical dose: 25-50 mg elemental iron daily, taken with vitamin C (200 mg) to enhance absorption. Avoid taking with calcium, tea, or coffee which inhibit absorption. Iron supplementation should only be initiated when ferritin is confirmed low — excess iron is toxic. Retest at 90 days.
Research
Key study
Iron deficiency without anaemia is a potential cause of fatigue: meta-analyses of randomised controlled trials and observational studies
Houston BL, Hurrie D, Graham J, et al.
BMJ Open (2018)
DOI: 10.1136/bmjopen-2018-022199Related Biomarkers
Related Guides
Test your Ferritin levels
Ferritin 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.