The causes of low ferritin but not anemia include frequent blood donation, gastrointestinal GI blood loss, increased physiological demand, medications, impaired gut absorption, dietary inadequacy and heavy menstrual bleeding.
Heavy menstrual bleeding is the most common cause of low ferritin without anemia, in premenopausal women, where the iron is lost via menstruation outpaces dietary intake.
Consuming insufficient iron, which is common in vegetarians and vegans is also a common cause of low ferritin without anemia because plant based non heme iron is harder for your body to absorb.
And conditions like inflammatory bowel disease or IBD, celiac disease, or even prior bariatric surgery also inhibit your body's ability to absorb iron, which can lead to low ferritin levels but not being anemia.
Even chronic use of antacids like proton pump inhibitors lowers your stomach acid, which is also necessary to absorb iron properly and can lead to low ferritin levels.
Pregnancy, lactation, puberty, or rigorous endurance training also rapidly deplete iron reserves and slow, often unseen blood loss from conditions like stomach ulcers, hemorrhoids or colon polyps can cause low ferritin levels without anemia.
And regular blood donors also frequently deplete their stored iron, which can lead to low ferritin without being anemic.
When you have low ferritin, the low ferritin levels can make you feel dizzy, persistently fatigued, cause brain fog, sometimes hair loss, shortness of breath, heart palpitations and even restless legs.
These symptoms of low ferritin levels can occur even before your full iron deficiency anemia develops.
Iron in the body is crucial for energy production and oxygen delivery and cognitive function and depleted iron reserves also impact your body in several ways by causing constant exhaustion, cognitive issues, physical weakness, sensory changes, skin and hair changes, sleep disturbances and mood changes.
Constant exhaustion is the most common symptom of low ferritin, which involves a deep, heavy lack of energy that doesn't improve even after a full night's sleep.
Cognitive issues that can result from low ferritin can result in brain fog, poor concentration and difficulty focusing, and are very common issues with low ferritin as your brain's iron pathways are affected.
When your ferritin levels are low it can result in shortness of breath with little activity, lightheadedness, dizziness and a rapid or pounding heartbeat or palpitations as your heart works harder to circulate oxygen.
And sensory changes from low ferritin include frequent headaches, cold hands and feet, brittle nails and unusual cravings such as chewing ice also known as (pica).
Skin and hair changes from low ferritin levels include increased hair shedding, thinning or pale and sallow skin and a strong urge to move your legs at night also known as Restless Leg Syndrome and frequent night waking.
Mood changes from low ferritin include increased irritability, mood swings, anxiety or symptoms of depression.
Dangerously low ferritin levels are when your ferritin levels are below 15 ng/mL for adults.
When your ferritin levels are below 10 ng/mL your ferritin levels are considered to be severely depleted.
Ferritin in the body is a specialized protein, which safely stores iron inside of your cells and then releases it when the body needs it.
Measuring your body's blood ferritin levels also indicates your total iron reserves.
And having low ferritin levels also points to an iron deficiency like anemia, and high ferritin levels can indicate you have iron overload or systemic inflammation.
The reason why the ferritin levels matters in the body and why ferritin itself matters is because iron is vital to the body for producing red blood cells and transporting oxygen, although it can also be highly toxic in it's free state.
Ferritin also acts as the body's "iron storage closet," safely sequestering the mineral to prevent cellular damage while also keeping it available for essential bodily functions.
A ferritin blood test is used to measure the concentration of the ferritin protein in your blood to give your doctor an accurate picture of your body's stored iron.
And the ferritin blood test is often ordered alongside tests like a Complete Blood Count or CBC or Total Iron Binding Capacity or TIBC.
The typical ferritin reference ranges can vary slightly between each laboratory but are often the following reference ranges:
Men: Typically 20 to 500 nanograms per milliliter (ng/mL) (or up to 336 mcg/L depending on the lab)
Women: Typically 20 to 200 ng/mL (or 11 to 307 mcg/L)
Test results for ferritin levels below the standard above reference range mean that your iron reserves are depleted.
Depleted iron levels are most commonly caused by heavy menstrual bleeding, poor dietary iron absorption, or even pregnancy.
The symptoms of low iron levels include:
Restless leg syndrome.
Shortness of breath.
And unexplained fatigue and weakness.
Results higher than the expected ferritin ranges can indicate you have an accumulation of excess iron or it may even signal an underlying health issue.
Having elevated levels of ferritin can also be caused by conditions like Hemochromatosis, which is a genetic disorder that causes iron overload, chronic inflammation, liver disease or even alcohol misuse.
When your ferritin dips to dangerous levels, the body lacks the reserve it needs to produce hemoglobin, which results in symptoms like:
Chronic, severe fatigue and weakness.
Pale skin.
Dizziness or lightheadedness.
Headaches and brain fog.
Shortness of breath.
And fast or irregular heartbeat.
Key Details on the body's Ferritin Levels include the following:
Normal Ranges of ferritin: Standard reference ranges of ferritin typically fall between 20 to 200 ng/mL for women and 20 to 500 ng/mL for men.
Absolute Iron Deficiency: Any value under 12 ng/mL in children and 15 ng/mL in adults as absolute iron deficiency.
Many experts also now consider levels of ferritin under 30 ng/mL to indicate depleted stores.
"Normal" Labs Can Still Be Low: You can have "iron deficiency without anemia".
If your hemoglobin is normal but your ferritin is under 30 ng/mL, you may still experience severe symptoms.
Inflammation Caveat: Ferritin is an "acute-phase reactant," meaning it can temporarily rise during periods of infection, chronic inflammation, or illness.
In these cases, a "normal" ferritin reading can falsely mask severe iron deficiency.