Ferritin

What Is Ferritin?

Ferritin is a protein that stores iron inside your cells, kind of like a tiny vault. When your body needs iron — say, to make new red blood cells — it opens these vaults and releases iron into the bloodstream. A ferritin blood test measures how much of this storage protein is circulating in your blood, which gives your doctor a reliable estimate of how much iron your body has tucked away in reserve.

If serum iron is like checking how much cash is in your wallet right now, ferritin is like checking your savings account. It tells you whether you have a healthy reserve or whether you are running dangerously low.

What Does It Measure?

A ferritin test measures the concentration of ferritin protein in your blood. Because ferritin reflects your body's total iron stores, it is considered the single most useful test for detecting iron deficiency. While serum iron levels can swing wildly throughout the day, ferritin provides a much steadier and more reliable picture.

That said, ferritin isn't perfect. It is also an "acute phase reactant," which means your body makes more of it when there is inflammation, infection, or illness. So a person could have normal or even high ferritin levels while still being iron deficient if they also have an ongoing inflammatory condition. Your doctor takes this into account when interpreting your results.

Normal Ranges

| Group | Range | Unit | |---|---|---| | Adult men | 24 – 336 ng/mL | ng/mL | | Adult women (premenopausal) | 11 – 307 ng/mL | ng/mL | | Adult women (postmenopausal) | 12 – 263 ng/mL | ng/mL | | Children (6 months – 15 years) | 7 – 140 ng/mL | ng/mL | | Newborns | 25 – 200 ng/mL | ng/mL | | Pregnant individuals | 10 – 150 ng/mL | ng/mL |

Optimal ferritin is often considered to be above 40 to 50 ng/mL for most adults, even though the "normal" range starts lower. Many practitioners find that symptoms of iron deficiency can appear when ferritin drops below 30 ng/mL.

What Does a High Level Mean?

Elevated ferritin means your body is storing more iron than usual, or that something is triggering extra ferritin production. It deserves attention because chronically high iron levels can damage your organs.

Possible conditions associated with high ferritin:

• Hemochromatosis — a hereditary condition causing excessive iron absorption
• Chronic inflammation from conditions like rheumatoid arthritis, lupus, or inflammatory bowel disease
• Liver disease, including fatty liver disease, hepatitis, and cirrhosis
• Chronic infections
• Certain cancers, particularly lymphoma and leukemia
• Frequent alcohol use
• Metabolic syndrome and obesity

Common symptoms of high ferritin:

• Joint pain and stiffness
• Chronic fatigue
• Abdominal pain, particularly in the upper right area near the liver
• Unexplained weight loss
• Heart palpitations or irregular heartbeat
• Skin color changes (bronze or gray tones)

Recommended next steps:

• Your doctor will check transferrin saturation to distinguish between iron overload and inflammation
• Liver function tests may be ordered
• Genetic testing for the HFE gene (hemochromatosis) may be recommended
• An inflammation marker like CRP can help determine if inflammation is driving the result
• If iron overload is confirmed, therapeutic phlebotomy is the standard treatment

What Does a Low Level Mean?

Low ferritin is one of the clearest signals that your body's iron reserves are depleted. It is the earliest indicator of iron deficiency — ferritin drops before serum iron does and long before you develop full-blown anemia.

Possible conditions associated with low ferritin:

• Iron deficiency, the most common nutritional deficiency worldwide
• Iron deficiency anemia (when stores are so depleted that red blood cell production suffers)
• Chronic blood loss from heavy periods, gastrointestinal bleeding, or frequent blood donation
• Inadequate dietary iron intake — common in vegetarians, vegans, and restrictive dieters
• Malabsorption conditions like celiac disease, Crohn's disease, or after gastric bypass surgery
• Pregnancy and breastfeeding, which increase iron demands significantly

Common symptoms of low ferritin:

• Exhaustion that sleep doesn't fix
• Brain fog and difficulty concentrating
• Hair thinning or hair loss (this is a big one that many people don't realize is connected to iron)
• Restless legs, especially at night
• Frequent headaches
• Dizziness or lightheadedness
• Getting sick more often than usual

Recommended next steps:

• Your doctor may order a full iron panel and complete blood count
• Identify and address the root cause of iron depletion
• Iron supplementation is often prescribed — ferrous sulfate, ferrous gluconate, or ferrous bisglycinate are common forms
• In severe cases, intravenous (IV) iron infusion may be needed
• Recheck ferritin after 8 to 12 weeks of supplementation to track progress

When Should You Get Tested?

Ferritin testing is recommended when you experience persistent fatigue, hair loss, difficulty concentrating, or other symptoms of iron deficiency. It is particularly important for women with heavy menstrual periods, pregnant women, growing teenagers, athletes (especially endurance athletes who lose iron through sweat and foot-strike hemolysis), and people following plant-based diets.

Doctors also order ferritin when screening for iron overload, monitoring known hemochromatosis, evaluating unexplained high liver enzymes, or assessing chronic inflammatory conditions.

If you have been taking iron supplements, ferritin is the best way to check whether they are actually replenishing your stores.

How to Improve Your Levels

If your ferritin is too low:

• Increase dietary iron from both animal sources (heme iron: red meat, liver, shellfish, dark poultry meat) and plant sources (non-heme iron: lentils, chickpeas, tofu, fortified cereals, pumpkin seeds)
• Always pair plant-based iron foods with vitamin C to boost absorption — a squeeze of lemon on your lentils goes a long way
• Avoid calcium supplements, coffee, and tea within an hour of eating iron-rich meals, as they interfere with absorption
• Take iron supplements as directed — many people tolerate them better when taken every other day rather than daily
• Be patient. It can take 3 to 6 months to rebuild ferritin stores, even with supplementation

If your ferritin is too high:

• If due to iron overload, regular blood donation or therapeutic phlebotomy reduces iron stores
• Limit iron-rich foods and avoid iron-fortified products
• Reduce alcohol intake, as alcohol worsens liver iron accumulation
• Treat underlying inflammation or infection
• Follow up regularly with your doctor to monitor levels

Frequently Asked Questions

Q: My ferritin is "normal" at 15 ng/mL but I still feel terrible. Is that really normal?

Many experts believe that a ferritin of 15 ng/mL, while technically within the lab reference range, is far from optimal. Research suggests that symptoms like fatigue, hair loss, and brain fog can occur at ferritin levels below 30 to 50 ng/mL. Some practitioners aim for a ferritin of at least 50 ng/mL, especially for women. It is worth having an honest conversation with your doctor about how you feel, not just where you fall on the range.

Q: Can ferritin be high even if I'm iron deficient?

Yes, this is a tricky but important scenario. Because ferritin rises in response to inflammation, infection, liver disease, and other conditions, it can mask an underlying iron deficiency. If your doctor suspects this, they will look at additional markers like transferrin saturation, serum iron, and TIBC, along with inflammatory markers like CRP, to get the full picture.

Q: How often should I recheck my ferritin?

If you are actively supplementing to correct a deficiency, most doctors recommend rechecking ferritin after 8 to 12 weeks. Once your levels have normalized, an annual check is usually sufficient unless you have ongoing risk factors like heavy periods or a malabsorption condition. If you are being treated for iron overload, your doctor may check ferritin every 2 to 3 months until levels are well controlled.

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This content is for educational purposes only and is not medical advice. Always consult your healthcare provider about your lab results.