Is my Hemoglobin normal?
Free blood test checker · Standard + longevity-optimal ranges
What is a normal Hemoglobin level?
Hemoglobin is the protein in red blood cells that carries oxygen throughout your body. Low hemoglobin (anemia) causes fatigue, weakness, and shortness of breath. Normal range is 12.0-17.5 g/dL, varying by sex. Over 3 million Americans have anemia, making it one of the most common blood conditions.
| Range | Values |
|---|---|
| Standard Reference | 12–17.5 g/dL |
| Low Risk | < 10 g/dL |
What causes abnormal Hemoglobin levels?
Low hemoglobin (anemia) is caused by iron deficiency (the most common cause worldwide), vitamin B12 or folate deficiency, chronic kidney disease (reduced erythropoietin), chronic inflammation, blood loss (heavy menstruation, GI bleeding), bone marrow disorders, hemolytic anemias, and thalassemia. High hemoglobin can be caused by dehydration, living at high altitude, smoking, polycythemia vera, or chronic lung disease.
When should you see a doctor?
See your doctor if hemoglobin is below 12.0 g/dL (women) or 13.5 g/dL (men), or if you experience fatigue, weakness, pale skin, shortness of breath, dizziness, or cold hands and feet. Also consult if hemoglobin is above 17.5 g/dL (men) or 15.5 g/dL (women).
Hemoglobin and longevity
Hemoglobin is central to oxygen delivery and exercise capacity — two pillars of healthspan. Mild anemia is remarkably common in aging populations and often dismissed as "normal aging," but even borderline-low hemoglobin reduces exercise tolerance, cognitive function, and quality of life. Iron deficiency is the most treatable cause. Endurance athletes should be aware that training-induced hemolysis (foot-strike hemolysis, mechanical destruction of red blood cells) and plasma volume expansion can mask true hemoglobin levels. Always test hemoglobin alongside ferritin, iron, and reticulocyte count for the complete picture.
Where to get a Hemoglobin test
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Related biomarkers
These biomarkers are often tested alongside Hemoglobin for a more complete picture.
Frequently asked questions
What is a normal hemoglobin level?
What causes low hemoglobin?
How can I increase my hemoglobin?
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Sources: Reference ranges based on AHA/ACC, ADA, and AACE clinical guidelines. Biological variation data from Ricos/Westgard database. Longevity-optimal ranges reflect targets used by preventive and functional medicine practitioners.
Last reviewed: April 2026. This tool provides general health information and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your healthcare provider about your specific results.