Ferritin
Ferritin is the main intracellular iron storage protein, and a small amount circulates in blood in proportion to total body iron stores. Low ferritin is the earliest and most specific marker of iron deficiency, often preceding anemia. High ferritin can reflect iron overload (hemochromatosis), but is also an acute phase reactant that rises with inflammation, infection, and liver disease.
Units: ng/mL; some labs report µg/L (same number in both units). Check the units on your report before comparing to any range here.
Optimal range: who says what
Institutions, researchers and practitioners draw the line in different places. Each position is listed with who holds it and, where a document states it, a link. How we verify ranges.
- Institution or studyBelow 15 ng/mL defines iron deficiencyWHO guideline on ferritin thresholds (2020)Thresholds differ for children and in pregnancy
- Institution or study20-200 ng/mL (men)AASLD hemochromatosis guideline (2011): values in normal subjectsIn HEIRS screening, ferritin was above 300 ng/mL in 88% of male C282Y homozygotes; ferritin is also raised by inflammation
- Institution or study15-150 ng/mL (women)AASLD hemochromatosis guideline (2011): values in normal subjectsIn HEIRS screening, ferritin was above 200 ng/mL in 57% of female C282Y homozygotes; ferritin is also raised by inflammation
- Named practitioner50-100 ng/mL women / 50-125 menLife Extension · Lab Testing Protocol (Suggested Optimal Ranges)Disclosure: Life Extension sells lab panels that appear in our blood-test comparisons.
- Named practitioner50-150 ng/mLTracey O'Shea (Kresser Institute) · The Lipid Panel Was Fine. The Patient Was Not: A Case in Advanced Cardiovascular Risk Assessment
- Named practitionerWomen: no need to raise above 80 ng/mL; above about 140-150 ng/mL means overloadChris Kresser · Poor Sleep Patterns, Low Ferritin Levels, and Juice Fasting (RHR transcript)Spoken on a podcast: "there is no need to increase ferritin above 80" and, in women, "the upper end of ferritin, the safe range, is about 140 or 150."
- Lab reference intervalMen: 24-336 ng/mL, Women: 11-307 ng/mLWhat a lab report flags against. A lab interval is not an optimal target.
Practitioner targets are individual positions, often tighter than guideline ranges. Each was checked against its article before publishing.
18 of 21 itemized panels
Vitamins & Nutrients
What is Ferritin?
Ferritin is the primary storage form of iron in your body, found mainly in the liver, spleen, bone marrow, and muscles. Serum ferritin (measured in blood tests) reflects total body iron stores: low ferritin indicates iron deficiency, while high ferritin may indicate iron overload, inflammation, or chronic disease. Ferritin is a more sensitive marker of iron status than serum iron or hemoglobin—ferritin drops FIRST as iron stores deplete, long before anemia develops. This is why checking ferritin is essential for detecting early iron deficiency.
Lab reference intervals for ferritin are wide: the standard interval shown on this page is 24-336 ng/mL for men and 11-307 ng/mL for women, and intervals vary by lab. Low ferritin without anemia can still cause symptoms. In a randomized trial of non-anemic women with fatigue, intravenous iron helped those whose ferritin was 15 ng/mL or lower (Krayenbuehl 2011), and restless legs guidelines rate oral iron as possibly effective when ferritin is 75 ng/mL or lower (Allen 2018). Women of childbearing age, vegetarians, athletes, and frequent blood donors are at highest risk of low ferritin. Targets above the lab minimum are listed with their sources in the ranges section.
Ferritin is also an acute-phase reactant—it rises during inflammation or infection, which can mask true iron deficiency. If you have both inflammation (elevated CRP) and low-normal ferritin (30-50 ng/mL), you may actually be iron deficient despite ferritin appearing "normal." In this case, check additional iron markers: serum iron, TIBC, transferrin saturation, and consider soluble transferrin receptor (sTfR).
Why Ferritin (Iron Stores) Matters for Longevity
- Oxygen transport: Iron is the core of hemoglobin (carries oxygen in red blood cells) and myoglobin (stores oxygen in muscles). Low iron = less oxygen delivery = fatigue, weakness, shortness of breath.
- Energy production: Iron is a cofactor for cytochrome enzymes in the mitochondrial electron transport chain. Low iron impairs ATP production, causing fatigue even without anemia.
- Cognitive function: Iron is required for neurotransmitter synthesis (dopamine, serotonin, norepinephrine) and myelin formation. Low iron causes brain fog, poor concentration, depression, and impairs child cognitive development.
- Thyroid function: Iron is required for thyroid peroxidase enzyme, which synthesizes thyroid hormones. Iron deficiency impairs T4→T3 conversion and can worsen hypothyroidism.
- Immune function: Iron is required for immune cell proliferation and function. Both too little (impaired immunity) and too much (promotes bacterial growth) are problematic.
- Physical performance: Low ferritin impairs exercise capacity, endurance, and muscle recovery. Athletes with ferritin <50 ng/mL have reduced performance.
Interpretation bands (curated, PMID-backed)
Holder: OptimizeBiomarkers editorial synthesis of: Total and cause-specific mortality by moderately and markedly increased ferritin concentrations: general population study and metaanalysis (Ellervik et al., 2014); Association between serum ferritin and mortality: findings from the USA, Japan and European Dialysis Outcomes and Practice Patterns Study (Karaboyas et al., 2018); A ferritin level >50 microg/L is frequently consistent with iron deficiency (Koulaouzidis et al., 2009). No single paper sets these cutoffs; for attributed targets see who says what.
Optimal (Longevity)70-100 ng/mL▼
- Target for optimal energy, cognitive function, athletic performance
- Many functional medicine doctors target >70 ng/mL
Adequate (Standard)50-70 ng/mL▼
- Sufficient to prevent symptoms in most people
- May be suboptimal for athletes or those with high iron needs
Suboptimal (Low-Normal)30-50 ng/mL▼
- Low-normal
- May cause fatigue, hair loss, restless legs, reduced exercise capacity
- Consider iron supplementation
Iron Deficiency<30 ng/mL▼
- Iron deficiency without anemia
- Causes fatigue, brain fog, hair loss, restless legs, cold intolerance
- Supplement with iron
- Total and cause-specific mortality by moderately and markedly increased ferritin concentrations: general population study and metaanalysis.
- Association between serum ferritin and mortality: findings from the USA, Japan and European Dialysis Outcomes and Practice Patterns Study.
- A ferritin level >50 microg/L is frequently consistent with iron deficiency.
What raises or lowers Ferritin
Causes of high Ferritin
- Hereditary hemochromatosis: Genetic disorder (HFE gene mutations C282Y, H63D) causing excessive iron absorption. Most common genetic disorder in Caucasians (1:200-300).
- Excessive iron supplementation: Taking high-dose iron without deficiency.
- Frequent blood transfusions: Chronic anemia (thalassemia, sickle cell) requiring transfusions leads to iron overload.
- Chronic liver disease: Cirrhosis, hepatitis impair iron regulation and raise ferritin.
- Inflammation or infection: Acute-phase reaction raises ferritin (check CRP to distinguish from true iron overload).
- Cancer: Some cancers (liver, pancreatic, leukemia) raise ferritin.
- Alcohol abuse: Damages liver, impairs iron regulation.
Causes of low Ferritin
- Heavy menstrual bleeding: Most common cause in premenopausal women. Loses 30-50 mg iron per cycle if heavy.
- Pregnancy and breastfeeding: Increased iron requirements (27 mg/day pregnant, 9-10 mg/day lactating). Fetus depletes maternal iron stores.
- Vegetarian/vegan diet: Plant iron (non-heme) poorly absorbed (2-20%) vs meat iron (heme, 15-35%). Vegetarians need more dietary iron because plant iron is absorbed less well.
- Frequent blood donation: Each donation removes iron, and frequent donors often have low ferritin.
- GI blood loss: Chronic NSAID use (aspirin, ibuprofen), ulcers, gastritis, inflammatory bowel disease, colon cancer, celiac disease.
- Malabsorption: Celiac disease (most common), atrophic gastritis, H. pylori, gastric bypass, chronic diarrhea.
- Intense endurance training: Athletes lose iron via foot-strike hemolysis, GI bleeding, sweat. "Sports anemia."
- Rapid growth: Adolescents, especially girls, have increased iron needs.
- Chronic kidney disease: Impaired erythropoietin production reduces iron utilization.
Symptoms when Ferritin is high or low
When high
High ferritin (>300 ng/mL men, >200 ng/mL women) may indicate iron overload, inflammation, or chronic disease. Symptoms of iron overload (hemochromatosis):
- Joint pain, especially knuckles
- Fatigue, weakness
- Abdominal pain
- Loss of libido, erectile dysfunction
- Bronze or gray skin discoloration
- Diabetes (iron damages pancreas)
- Liver disease, cirrhosis
- Heart arrhythmias, heart failure (iron deposits in heart)
- Increased infection risk (excess iron promotes bacterial growth)
High ferritin from inflammation is most common (check CRP). True iron overload (hemochromatosis) is less common but serious.
When low
- Fatigue, exhaustion, low energy (most common symptom)
- Weakness, difficulty with physical exertion
- Shortness of breath, especially with activity
- Pale skin, pale conjunctiva (inner eyelids)
- Cold intolerance, always feeling cold
- Brain fog, poor concentration, memory problems
- Headaches, dizziness
- Hair loss, brittle nails
- Restless leg syndrome (irresistible urge to move legs, worse at night)
- Pica (craving non-food items like ice, dirt, starch)
- Rapid heartbeat, palpitations (if anemic)
- Decreased immune function, frequent infections
- Impaired exercise performance, reduced endurance
Low ferritin <30 ng/mL causes symptoms even without anemia. Severe deficiency <12 ng/mL often accompanied by anemia (low hemoglobin).
How to move Ferritin
Effect sizes (how much something moves the marker) appear only where the paper cited under the item states them. Talk to your clinician before starting or changing any medication or supplement.
Iron Supplementation (Dose and Form)
- Ferrous sulfate: 325 mg (65 mg elemental iron) once or twice daily. Cheapest and most common form but causes GI side effects (nausea, constipation, black stools). Take on empty stomach with vitamin C (enhances absorption).
- Ferrous bisglycinate (chelated iron): 25-50 mg elemental iron daily. Gentler on stomach, better tolerated, higher bioavailability than sulfate. Preferred form for most people.
- Iron polysaccharide: 150 mg elemental iron daily. Non-ionic form, minimal GI side effects.
- Timing: Take iron away from meals (or with low-phytate meals), away from calcium, tea, coffee (inhibit absorption). Pair with vitamin C (enhances absorption).
- Duration: Expect 2-3 months to raise ferritin significantly. Retest after 3 months and adjust dose.
Dietary Sources of Iron (Heme vs Non-Heme)
- Heme iron (animal sources, highly bioavailable, 15-35% absorbed): Red meat (beef, lamb), organ meats (liver), poultry, fish, shellfish (oysters, clams). Liver is extraordinarily high in iron (5-10 mg per 3 oz).
- Non-heme iron (plant sources, poorly absorbed, 2-20% absorbed): Spinach, lentils, chickpeas, tofu, fortified cereals, dark chocolate. Absorption enhanced by vitamin C, impaired by phytates (grains, legumes), tannins (tea, coffee), calcium.
- Vegetarians and vegans need more dietary iron because plant (non-heme) iron is absorbed less well. Consider iron supplementation if ferritin <50 ng/mL.
Optimize Iron Absorption
- Vitamin C: 100-200 mg with iron-containing meals increases non-heme iron absorption. Take vitamin C supplement with iron pill.
- Avoid inhibitors: Don't consume tea, coffee, calcium supplements, or high-phytate foods (bran, legumes) within 2 hours of iron-rich meals or supplements.
- Cook in cast iron: Acidic foods cooked in cast iron (tomato sauce, chili) absorb significant iron from the cookware.
- Spacing: Take iron supplements away from calcium, magnesium, zinc (compete for absorption).
Treat Underlying Causes of Low Ferritin
- Heavy menstrual bleeding: Most common cause in premenopausal women. Consider hormonal birth control, tranexamic acid, or IUD to reduce bleeding.
- GI blood loss: Chronic NSAID use, ulcers, gastritis, celiac disease, inflammatory bowel disease, colon polyps/cancer. Investigate if unexplained iron deficiency or ferritin dropping despite supplementation.
- Malabsorption: Celiac disease (most common), atrophic gastritis, H. pylori infection, gastric bypass. May require IV iron if oral supplementation fails.
- Frequent blood donation: Each donation lowers ferritin. Donors should check ferritin annually and supplement if <50 ng/mL.
Evaluate Iron Overload if Ferritin Very High
If ferritin >300 ng/mL (men) or >200 ng/mL (women) without supplementation:
- Check CRP: If CRP elevated, high ferritin is likely inflammation, not iron overload.
- Check transferrin saturation and serum iron: If transferrin saturation >45%, consider hemochromatosis.
- Hemochromatosis genetic testing: HFE gene mutations (C282Y, H63D). If positive, requires phlebotomy (blood removal) to prevent iron-induced organ damage (liver cirrhosis, diabetes, heart failure).
- Liver disease, cancer, chronic infection can also raise ferritin.
When to retest
- Baseline: Check ferritin if symptoms (fatigue, hair loss, restless legs) or risk factors (heavy periods, vegetarian, frequent donor, athlete).
- After starting iron supplementation: Retest in 3 months. Expect ferritin to rise 30-50 ng/mL with consistent supplementation. Adjust dose based on response. Life Extension suggests 50-100 ng/mL for women and 50-125 for men (see who says what above).
- Once ferritin reaches your target: Retest every 6-12 months to maintain. May need maintenance dose (25-50 mg every other day) to prevent recurrence, especially if underlying cause persists.
- If high ferritin (>300 men, >200 women): Check CRP, transferrin saturation, consider hemochromatosis testing. Retest in 3 months.
- If unexplained low ferritin despite supplementation: Investigate for GI blood loss (endoscopy, colonoscopy) or malabsorption (celiac testing).
Scientific Evidence
Iron for Fatigue Without Anemia
In a randomized trial of 90 premenopausal women with fatigue, ferritin of 50 ng/mL or lower, and normal hemoglobin, 800 mg of intravenous iron did not significantly reduce fatigue overall at 6 weeks. In women with ferritin of 15 ng/mL or lower, fatigue fell 1.8 points on a 0-10 scale versus 0.4 with placebo, and 82% versus 47% reported improvement.
Iron Treatment for Restless Legs Syndrome
International Restless Legs Syndrome Study Group guidelines conclude that IV ferric carboxymaltose (1,000 mg) is effective for moderate to severe RLS in adults with ferritin below 300 µg/L, and that oral iron (65 mg elemental) is possibly effective when ferritin is 75 µg/L or lower.
Which Providers Test Ferritin?
Cheapest: Empirical Health at $190/year. Most comprehensive: Function Health, 160+ biomarkers for $365/year.
18 panels that include it, cheapest first
| Provider | Annual Cost | Total Biomarkers | $/Biomarker |
|---|---|---|---|
| $190 | 100+ | $1.90 | |
| $297 | 100+ | $2.97 | |
 Superpower | $349 | 100+ | $3.49 |
| $349 | 75+ | $4.65 | |
 WHOOP Advanced Labs | $349 | 65 | $5.37 |
 Function Health | $365 | 160+ | $2.28 |
| $365 | 100+ | $3.65 | |
| $375 | 108 | $3.47 | |
| $449 | 83 | $5.41 | |
| $495 | 80+ | $6.19 | |
| $499 | 100+ | $4.99 | |
| $700 | 138 | $5.07 | |
| $829 | 54 | $15.35 | |
| $895 | 100+ | $8.95 | |
| $996 | 59 | $16.88 | |
| $1188 | 70+ | $16.97 | |
| $1198 | 40+ | $29.95 | |
| $1950 | 130+ | $15.00 |
$/Biomarker is annual cost divided by the panel's advertised biomarker count, not the price of this one test. We track 23 blood test providers (32 plans); 21 of those plans are itemized marker by marker. Compare all of them.
3 itemized panels do not include Ferritin
11 providers not itemized in our matrix
We have not itemized these marker by marker (some sell tests one at a time), so this page cannot say whether they offer Ferritin. Check with them directly.
Life Extension Standard · Quest Health · Ultrahuman Blood Vision · Lifeforce · Hundred Health · Personalabs · Walk-In Lab · HealthLabs · WHOOP Specialized Panels · Marek Health Essential · Vitality Blueprint Upload
Experts discussing Ferritin
Podcast episodes where clinicians and researchers cover this marker in depth. Curated by hand; an episode is listed only when the marker is a substantial topic, not a passing mention.
Frequently Asked Questions
What is the optimal range for Ferritin?
Published positions differ: Below 15 ng/mL defines iron deficiency (WHO guideline on ferritin thresholds (2020)); 20-200 ng/mL (men) (AASLD hemochromatosis guideline (2011): values in normal subjects); 15-150 ng/mL (women) (AASLD hemochromatosis guideline (2011): values in normal subjects). Named practitioners target: 50-100 ng/mL women / 50-125 men (Life Extension); 50-150 ng/mL (Tracey O'Shea (Kresser Institute)); Women: no need to raise above 80 ng/mL; above about 140-150 ng/mL means overload (Chris Kresser). Lab reference interval: Men: 24-336 ng/mL, Women: 11-307 ng/mL. That is what a lab report flags against, not an optimal target.
Which blood test providers include Ferritin?
18 of the 21 blood testing panels we itemize marker by marker include Ferritin in their panels. This biomarker is widely available across major providers.
Related: YouBoost rates lifestyle and supplement interventions by evidence.
Medical Disclaimer
This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider about your specific health needs.
Last reviewed Sep 23, 2026 · First published Sep 30, 2025