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Serum ferritin (Ferritin)

Updated October 31, 2026 · 43 sources · Written by the AumniVIDA team

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What is Ferritin?

Ferritin is the protein that stores iron inside your cells, and a blood ferritin test estimates how much iron you have in reserve. It is the most accurate single blood test for iron deficiency. Below 30 ng/mL (30 µg/L)30 µg/L (30 ng/mL) usually means low stores, but inflammation, liver disease and alcohol can push it up.

Cutaway illustration of a spherical ferritin protein shell made of 24 interlocking subunits, with a dense mineral iron core visible inside.
Ferritin is a hollow protein shell that locks iron away in a safe mineral core, up to about 4,500 iron atoms per molecule.

Questions people ask about Ferritin

  1. 01What does low ferritin mean?Low ferritin means your iron stores are running out. Below 15 ng/mL (15 µg/L)15 µg/L (15 ng/mL) stores are empty, and ASH 2026 counts 30 ng/mL or lower as iron deficiency in most adults. It can cause fatigue before anemia appears. The usual causes are menstruation, pregnancy, diet, blood donation and gut blood loss, so the cause needs finding.Read the answer
  2. 02What does high ferritin mean?High ferritin usually signals inflammation, fatty liver, alcohol, metabolic syndrome or cell damage rather than too much iron: only about 10% of cases reflect iron overload. Transferrin saturation separates them. Ferritin above 200 ng/mL in women or 300 ng/mL in men with saturation over 45% to 50% suggests overload such as hemochromatosis.Read the answer
  3. 03How to increase ferritinFerritin rises when you absorb more iron than you lose.Read the answer
  4. 04What is a normal ferritin level?A typical lab ferritin range runs from about 15 to 30 ng/mL at the low end to about 200 ng/mL in women and 300 ng/mL in men.Read the answer
  5. 05Ferritin test: what it measures and how to prepareA ferritin test is a routine blood draw that estimates your iron stores.Read the answer
  6. 06Ferritin vs iron: what is the difference?Ferritin is the protein that stores iron, so the ferritin test estimates your iron reserves.Read the answer

Key takeaways

  1. 1

    Ferritin is the best single blood test for iron stores: below 15 ng/mL is about 99% specific for iron deficiency [1].

  2. 2

    Cutoffs have moved up: WHO still uses 15 ng/mL, the AGA uses 45 ng/mL with anemia, and ASH 2026 uses 30 ng/mL or lower for most adults [2] [3] [4].

  3. 3

    Inflammation, fatty liver, alcohol and metabolic syndrome raise ferritin; only about 10% of high results in routine practice are iron overload [5].

  4. 4

    Read ferritin with transferrin saturation and CRP: saturation above 45% to 50% with high ferritin suggests overload [6].

  5. 5

    Low ferritin needs a cause: about a third of men and postmenopausal women with iron deficiency anaemia have an underlying problem, usually in the gut [1].

  6. 6

    Iron supplements should follow a test and a clinician's plan; alternate-day dosing absorbs better and upsets the gut less [7] [8].

What is ferritin?

Ferritin is the protein your cells use to store iron. A small amount leaks into the blood, and that blood level rises and falls with the size of your iron stores, which makes it the standard test for iron deficiency.

Ferritin is a hollow shell made of 24 protein subunits. Its inner cavity can hold up to about 4,500 iron atoms as a safe mineral core [9]. Storing iron this way does two jobs: it keeps a reserve for making red blood cells, and it keeps free iron, which damages cells, locked away.

Most ferritin sits inside liver cells, bone marrow and the immune cells called macrophages. The ferritin measured in a blood test is a small amount that reaches the blood. In 1972 the first serum ferritin assays showed that this blood level tracks storage iron: it was low in iron deficiency and very high in iron overload [10] [11]. Two years later a clinical evaluation confirmed serum ferritin as an index of iron stores [12].

Ferritin then became the strongest single test for iron deficiency. A 1992 overview of 55 studies that used bone marrow iron as the reference found it outperformed every other blood test, with an area under the curve of 0.95 [13].

The catch: ferritin also rises with inflammation, infection, liver damage and cancer. A high or normal result does not always mean full stores. The rest of this guide explains how to read it, and the question pages go deeper: low ferritin, high ferritin, normal ranges, the test itself, how to raise it and ferritin versus iron.

Fifty years of ferritin

  1. 1972

    First serum ferritin assays link blood ferritin to iron stores

  2. 1974

    Ferritin validated as an index of body iron stores

  3. 1992

    Systematic overview ranks ferritin the strongest test for iron deficiency

  4. 1996

    HFE gene for hereditary haemochromatosis identified

  5. 2004

    Hepcidin shown to switch off the iron exporter ferroportin

  6. 2017

    Alternate-day iron absorbs better than daily doses

  7. 2020

    WHO ferritin guideline; AGA adopts 45 ng/mL with anemia

  8. 2021

    Physiology points to about 25 ng/mL for women

  9. 2023

    Consensus definition of metabolic hyperferritinaemia

  10. 2026

    ASH sets 30 ng/mL for most adults

Ferritin went from a research assay in 1972 to the main iron test, and its deficiency cutoff has risen as physiology studies replaced expert opinion.

How does the body store and release iron?

The body has no way to excrete extra iron, so it controls iron at the gut. A liver hormone called hepcidin acts as the gate: high hepcidin blocks iron leaving gut cells and stores, and low hepcidin opens the gate.

Iron balance is set by absorption, because the body has no regulated way to get rid of iron [14]. People who do not menstruate lose less than 0.1% of their body iron a day, and diet replaces it [15].

The control point is hepcidin, a hormone made by the liver. Hepcidin binds ferroportin, the only known iron exporter on gut cells and macrophages, and makes the cell break it down [16]. With less ferroportin, iron stays inside the gut cell and is shed, or stays locked in storage.

Three things raise hepcidin:

  • Full iron stores. The body slows absorption when it has enough.
  • A recent iron dose. Oral doses of 60 mg or more raise hepcidin for about 24 hours and cut absorption from the next day's dose by 35% to 45% [17].
  • Inflammation. Infection and inflammatory disease raise hepcidin, which withholds iron from the blood even when stores are adequate [18]. Hard exercise does this too, which is one reason athletes run low [19].

Why inflammation raises ferritin

Ferritin is an acute phase reactant: its level climbs during the body's response to infection, injury and inflammation, whatever the iron stores are [5]. Cells make more ferritin in response to inflammatory signals, and damaged cells, especially liver cells, release ferritin into the blood. One review argues that most blood ferritin is a leakage product of cell damage, which would explain why it tracks so many diseases [20]. That argument is debated, but the practical point is agreed: an inflamed person can have a normal ferritin and still be short of iron.

How iron moves from food to storage

  1. Step 1

    Food

    Heme and nonheme iron

    Heme from meat and fish; nonheme from legumes and grains. Vitamin C helps; tea, coffee and phytate block.

  2. Step 2

    Gut lining cell

    Ferroportin door

    Ferroportin, the only known iron exporter, lets iron out into the blood.

  3. Step 3

    Blood

    Iron on transferrin

    Transferrin saturation is the share of transferrin carrying iron.

  4. Step 4

    Marrow and stores

    Red cells and ferritin

    Marrow builds hemoglobin; liver cells and macrophages store iron as ferritin. A little ferritin leaks into blood: the test.

  5. Step 5

    Liver hepcidin

    Closes the doors

    Hepcidin breaks down ferroportin in gut cells and macrophages, so iron stays put.

Full stores, a recent dose of 60 mg or more, and inflammation raise hepcidin (Nemeth 2004, Moretti 2015, Pasricha 2021). Low hepcidin opens the gate.

Hepcidin from the liver is the gate: when it rises, gut cells and stores hold iron back, which is why inflammation and daily high-dose iron both cut absorption.

Why does ferritin matter if your hemoglobin is normal?

Iron stores run out before anemia appears, so low ferritin can be the first sign of iron deficiency. Low iron without anemia is linked with fatigue and restless legs, and very high ferritin can be the first clue to iron overload.

Anemia is the late stage of iron deficiency. Harm can start before hemoglobin falls [18]. Physiology studies show that red cell production starts to strain at a ferritin of about 25 ng/mL (25 µg/L)25 µg/L (25 ng/mL) in women, well above the old 15 ng/mL cutoff [21] [22].

Fatigue

In a trial of 198 non-anemic menstruating women with fatigue and ferritin below 50 ng/mL, 12 weeks of 80 mg oral iron cut fatigue scores by 47.7% versus 28.8% with placebo [23]. A meta-analysis of 18 trials in non-anemic iron-deficient adults found a modest reduction in self-reported fatigue but no gain in measured physical capacity such as VO2max [24]. Fatigue has many causes, including thyroid disease (TSH), so low ferritin is one thing to check, not the whole answer.

Hair loss

Women with androgenetic alopecia and alopecia areata had lower mean ferritin than women without hair loss in a cross-sectional study [25]. Reviews conclude the evidence conflicts and is not strong enough to recommend iron for hair loss without anemia [26] [27].

Restless legs

Low brain iron is part of restless legs syndrome. The International Restless Legs Syndrome Study Group rates oral iron as possibly effective when ferritin is 75 ng/mL or lower, and intravenous ferric carboxymaltose as effective when ferritin is below 300 ng/mL [28]. That is a higher bar than for anemia.

Iron overload

At the other end, hereditary haemochromatosis makes the gut absorb too much iron. About 1 in 400 people of Northern European descent are affected [29], and in a screening study of 99,711 people most undiagnosed carriers of two C282Y variants had raised ferritin [30]. Untreated overload damages the liver, joints and pancreas, and phlebotomy prevents much of it [6]. See high ferritin.

What ferritin level is too low or too high?

Most labs flag ferritin below 15 to 30 ng/mL as low. Current guidelines put iron deficiency at 30 ng/mL or lower for most adults (ASH 2026) or below 45 ng/mL with anemia (AGA 2020). Above 150 ng/mL in women or 200 ng/mL in men, check transferrin saturation.

Ferritin is reported in ng/mL in the US and µg/L in most other countries. The two units are equal, so 30 ng/mL is 30 µg/L.

The table below puts every major threshold side by side. It is the comparison most pages leave out, and it explains why two clinicians can read the same result differently.

  • WHO 2020 keeps 15 ng/mL for deficiency in healthy people aged 5 and older, raises it to 70 ng/mL for adults with infection or inflammation, and sets overload screens at 150 ng/mL for menstruating women, 200 ng/mL for men and 500 ng/mL for adults who are unwell [2].
  • AGA 2020 recommends 45 ng/mL over 15 ng/mL when someone already has anemia [3].
  • BSG 2021 describes below 15 µg/L as absent stores and below 30 µg/L as low stores, with 45 µg/L giving a specificity of 0.92 [1].
  • ASH 2026 sets 30 ng/mL or lower for most adults, including menstruating and pregnant people, and up to 50 ng/mL for some higher-risk groups [4].
  • Physiology studies find hemoglobin starts to fall at about 25 ng/mL in women [21] [22], and about 30 ng/mL in older women and men who donate blood [31].

The move from 15 to 30 matters. A 1998 study found a cutoff of 12 µg/L caught only 25% of iron-deficient anemic patients, while 30 µg/L caught 92% with the same 98% specificity [32]. Lab reference ranges have not all caught up: the lower limit for most labs lies between 15 and 30 µg/L [1], and the upper limit is typically 200 µg/L in women and 300 µg/L in men [5].

Where your result falls is a starting point for a conversation with a clinician, not a diagnosis. The normal range page covers age, sex and pregnancy.

Ferritin thresholds by guideline, in ng/mL (equal to µg/L)
SourceIron deficiencyWith inflammationRaised or overload screen
WHO 2020Below 15 (age 5 and over); below 12 under age 5Below 70 in adults; below 30 under age 5Above 150 menstruating women, above 200 men; above 500 if unwell; never alone
AGA 2020Below 45 when anemia is presentNot separately setNot covered
BSG 2021Below 15 absent stores; below 30 low stores; 45 suggested cutoffUp to 100 may still be deficiencyAbove 150 makes absolute deficiency unlikely
ASH 202630 or lower for most adults; 50 or lower in some higher-risk groupsBelow 100, or transferrin saturation below 20%Not covered
IRLSSG 2018 (restless legs)Oral iron when 75 or lowerIV iron when below 300Not covered
EASL 2022 (haemochromatosis)Not coveredNot coveredAbove 200 women or 300 men with transferrin saturation above 45% or 50%
Typical lab rangeLower limit 15 to 30Not adjustedUpper limit about 200 women, 300 men

Where ferritin cutoffs fall

TypicalCheck transferrin saturationHighDeficiency in every guideline: 0 to 15 ng/mL (= µg/L)Deficiency in every guideline: 0 to 15 ng/mL (= µg/L)Low stores: 15 to 30 ng/mL (= µg/L)Low stores: 15 to 30 ng/mL (= µg/L)Low-normal: 30 to 50 ng/mL (= µg/L)Low-normal: 30 to 50 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)Deficiency in every guideline: 0 to 15 ng/mL (= µg/L)Deficiency in every guideline: 0 to 15 ng/mL (= µg/L)Low stores: 15 to 30 ng/mL (= µg/L)Low stores: 15 to 30 ng/mL (= µg/L)Low-normal: 30 to 50 ng/mL (= µg/L)Low-normal: 30 to 50 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Typical: 50 to 150 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)Check transferrin saturation: 150 to 300 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)High: 300 to 400 ng/mL (= µg/L)015WHO deficiency: 15 ng/mL (= µg/L)30ASH 2026 deficiency: 30 ng/mL (= µg/L)45AGA, with anemia: 45 ng/mL (= µg/L)70WHO, with inflammation: 70 ng/mL (= µg/L)100ASH, with inflammation: 100 ng/mL (= µg/L)150WHO overload screen, women: 150 ng/mL (= µg/L)200WHO overload screen, men: 200 ng/mL (= µg/L)400 ng/mL (= µg/L)
Deficiency in every guideline
0 to 15
Low stores
15 to 30
Low-normal
30 to 50
Typical
50 to 150
Check transferrin saturation
150 to 300
High
300 to 400
  • 15 ng/mL (= µg/L): WHO deficiency
  • 30 ng/mL (= µg/L): ASH 2026 deficiency
  • 45 ng/mL (= µg/L): AGA, with anemia
  • 70 ng/mL (= µg/L): WHO, with inflammation
  • 100 ng/mL (= µg/L): ASH, with inflammation
  • 150 ng/mL (= µg/L): WHO overload screen, women
  • 200 ng/mL (= µg/L): WHO overload screen, men
Guidelines disagree on where low ends: WHO uses 15 ng/mL, ASH 30 ng/mL and AGA 45 ng/mL, and the overload screen starts at 150 to 200 ng/mL.

How do you read ferritin when you have inflammation?

Inflammation pushes ferritin up, so a normal number can hide iron deficiency. WHO suggests treating ferritin below 70 ng/mL as deficient in inflamed adults, and ASH uses below 100 ng/mL or transferrin saturation below 20%, ideally with a CRP measured at the same time.

Because ferritin is an acute phase reactant, guidelines raise the cutoff or adjust the value when inflammation is present.

  • Raise the cutoff. WHO uses below 70 ng/mL in adults and below 30 ng/mL in young children with infection or inflammation [2]. ASH uses ferritin below 100 ng/mL or transferrin saturation below 20% [4]. BSG notes that up to 100 µg/L can still reflect iron deficiency when inflammation is present, while above 150 µg/L absolute deficiency is unlikely even with inflammation [1].
  • Measure inflammation alongside. WHO recommends measuring CRP and alpha-1-acid glycoprotein (AGP) with ferritin in settings with widespread infection, and defines raised levels as CRP above 5 mg/L and AGP above 1 g/L [2].
  • Adjust the number. In population surveys, a regression correction for CRP and AGP raised the estimated share of women with depleted stores by 2 to 8 percentage points [33].

For one person, the practical version is simple. Ask for CRP (or hs-CRP) and transferrin saturation alongside ferritin. A low saturation with a middling ferritin and a raised CRP points to iron deficiency hidden by inflammation. A high ferritin with a normal saturation and a raised CRP points to inflammation, not overload [5].

Lowering inflammation through diet, weight and treating the underlying disease can bring ferritin down without any change in iron. The anti-inflammatory diet protocol tracks the dietary side.

Reading ferritin with transferrin saturation and CRP

Read ferritin with transferrin saturation (TSAT) and CRP

  • Ferritin below 30 ng/mL (30 µg/L)30 µg/L (30 ng/mL), any CRPIron deficiency: find the cause (BSG 2021, ASH 2026)
  • Ferritin 30 to 100 ng/mL (30 to 100 µg/L)30 to 100 µg/L (30 to 100 ng/mL), CRP above 5 mg/L, TSAT below 20%Iron deficiency still possible, hidden by inflammation (ASH 2026, WHO 2020)
  • High ferritin, normal TSAT, CRP above 5 mg/LInflammation is the likely driver, not overload (Sandnes 2021)
  • High ferritin, normal TSAT, normal CRPThink liver fat, metabolic syndrome or alcohol (Sandnes 2021, Valenti 2023)
  • Ferritin above 200 to 300 ng/mL (200 to 300 µg/L)200 to 300 µg/L (200 to 300 ng/mL) with TSAT over 45%Possible iron overload: HFE testing (EASL 2022)

Every pattern needs a clinician to confirm. Ferritin alone should never be used to diagnose overload (WHO 2020).

Ferritin alone can mislead: pair it with transferrin saturation to see iron in transit and CRP to see whether inflammation is inflating it.

What raises or lowers ferritin?

Blood loss, pregnancy, low iron intake, poor absorption and endurance training lower ferritin. Iron in food and supplements raises it slowly. Inflammation, liver disease, alcohol and metabolic syndrome raise it without adding iron, and only overload raises it alongside high transferrin saturation.

What lowers it. Menstrual blood loss and pregnancy are the most common causes of iron deficiency in premenopausal women; in men and postmenopausal women, gut blood loss and malabsorption are the most common [26]. Blood donation removes a large dose of iron at once: without supplements, 67% of donors had not rebuilt their stores 168 days later [34]. Iron deficiency affects about 15% to 35% of female and 5% to 11% of male athlete cohorts [19].

What raises it with iron. Diet and supplements raise ferritin slowly. Iron bioavailability is about 14% to 18% from mixed diets and 5% to 12% from vegetarian diets [14]. Heme iron from meat and fish is not blocked by tea the way plant iron is [35]. A cup of tea with a meal cut iron absorption by 64% and a cup of coffee by 39% in one isotope study [36]. Vitamin C counteracts the phytate in grains and legumes in single meals [37], though across a whole diet its effect is much smaller [38].

For oral iron, less often can mean more absorbed. Alternate-day dosing raised absorption from 16.3% to 21.8% [7], and a 2023 trial found equal ferritin with fewer gut side effects at equal total doses [8]. Iron supplements should follow a test and a clinician's plan, because a low ferritin needs its cause found and extra iron does harm in overload. The full list of levers is on how to increase ferritin.

What raises it without iron. Only about 10% of high ferritin results in routine practice reflect iron overload. The rest come from inflammation, metabolic syndrome, alcohol, cell damage and cancer [5]. Ferritin tied to insulin resistance and fatty liver now has a consensus name, metabolic hyperferritinaemia [39]; markers such as fasting insulin, HbA1c and triglycerides help show that pattern.

Diet patterns matter for both ends. A whole-food plant-based diet provides only nonheme iron, so pairing legumes with vitamin C and keeping tea away from meals helps. A carnivore diet is rich in heme iron, which matters for anyone with a high ferritin and high transferrin saturation.

Tea and coffee with a meal

Show the data
Tea and coffee with a meal
ItemValue (% less iron absorbed from the meal)LowHighNote
Cup of tea with the meal64
Cup of coffee with the meal39
Coffee 1 hour before the meal0No decrease seen
In a classic isotope study, one cup of tea with a hamburger meal cut iron absorption by 64% and one cup of coffee by 39%.

What does the evidence not show?

There is no agreed optimal ferritin for energy, hair or athletic performance. Thresholds above 30 to 50 ng/mL come from physiology and expert consensus, not trials showing better outcomes, and the benefit of lowering ferritin in metabolic hyperferritinaemia is unproven.

  • No proven optimal level. Numbers such as 50, 70 or 100 ng/mL for hair growth or performance circulate widely, but no trial has shown that pushing ferritin to a target above the deficiency range improves those outcomes. Trials in non-anemic adults show a modest effect on self-reported fatigue and none on measured physical capacity [24].
  • Hair loss. The link rests mostly on cross-sectional studies, and reviews call for placebo-controlled trials before recommending iron for hair [26] [27].
  • The cutoff itself. The 15 ng/mL threshold came from expert opinion [21]. Newer thresholds of 25 to 30 ng/mL rest on the point where hemoglobin and soluble transferrin receptor start to change [22] [4], which is a physiological signal rather than proof that treating at that level improves how people feel.
  • High ferritin without overload. Metabolic hyperferritinaemia is linked with cardiometabolic and liver disease, but there is no clear evidence that removing iron helps [39].
  • Inflammation adjustment for one person. Correction formulas were built for population surveys [33]. For an individual, clinicians still rely on raised cutoffs and companion tests.

These gaps are why a ferritin result is best read with a clinician who knows the rest of your history.

Why did the ferritin guidelines change?

The long-used 15 ng/mL cutoff came from expert opinion and misses many people with iron deficiency. Studies that track when red cell production starts to suffer point to about 25 to 30 ng/mL, and ASH adopted 30 ng/mL for most adults in 2026.

WHO kept its 15 µg/L cutoff in 2020 because it judged the evidence too thin to change it, while noting the threshold was based on expert opinion [2] [21]. Physiology studies since then have pointed higher:

  • US non-pregnant women: about 25 µg/L [21].
  • Women in 12 countries across four regions: 24.8 µg/L, which found iron deficiency in 36.0% of women versus 20.1% using the WHO cutoff [22].
  • Pregnancy: about 25 µg/L in the first trimester and 18 to 19 µg/L later [40].
  • Blood donors: 25.4 µg/L in women aged 18 to 49, 30.7 µg/L in women aged 50 to 75, and 32.5 µg/L in men [31].

In 2026 the American Society of Hematology set 30 ng/mL or lower as the threshold for most adults, with or without anemia [4]. The AGA had already moved to 45 ng/mL for people with anemia in 2020 [3]. Expect many lab reports to keep showing an older lower limit for a while; the guideline number is the one to discuss with a clinician.

The research

Foundational studies

The work that established what this marker means.

Guidelines and reviews

Where expert bodies and systematic reviews have landed.

Recent research

Notable work from the last three years.

What well-known voices say about Ferritin

Their positions, summarized in our words. Follow each link for the full context.

  • Jacquelyn Powers, MD, MSPediatric hematologist and chair of the American Society of Hematology iron deficiency guideline panel

    Powers argues that a normal-looking lab report often hides iron deficiency, because some reference ranges still treat very low ferritin as normal. She backs 30 ng/mL as the threshold for most adults, up to 50 ng/mL for people at higher risk such as those with heavy periods, wants labs to flag results below these limits automatically, and urges clinicians to apply the thresholds to the individual patient rather than mechanically.

    HCPLive interview on why normal ferritin can miss iron deficiency (2026)

  • Angela Weyand, MDPediatric hematologist at Michigan Medicine and lead author of a national study of iron deficiency in young females

    Weyand's team found that about 40% of US females aged 12 to 21 had iron deficiency, defined as ferritin below 25 µg/L, while only about 6% had iron deficiency anemia. She supports routine ferritin screening for adolescents and young women even without symptoms, along with diet counseling and supplements or intravenous iron when levels stay low.

    University of Michigan news release on iron testing in teen girls and young women (2023)

  • Michael Auerbach, MDHematologist and clinical professor of medicine at Georgetown University

    Auerbach holds that oral iron should stay first-line for most people, but that its side effects drive poor adherence. He argues that modern intravenous iron is far safer than early products, that reluctance to use it rests on outdated safety fears, and that it should be offered sooner to people who cannot tolerate or absorb tablets. He has disclosed honoraria from a maker of intravenous iron.

    How we diagnose and treat iron deficiency anemia, American Journal of Hematology (2016)

Watch

Talks and explainers worth your time. Nothing loads from YouTube until you press play.

  • Iron Physiology

    Armando HasudunganOpen on YouTube

    A clear illustrated walk through iron absorption, transport and ferritin storage, useful before reading any iron result.

  • Iron Studies - Serum Fe, TIBC, ferritin & Transferrin % Saturation

    Medicosis PerfectionalisOpen on YouTube

    Explains how ferritin, serum iron, TIBC and transferrin saturation move together in each common iron pattern.

  • E121 - Iron deficiency without anaemia

    Australian PrescriberOpen on YouTube

    A clinician-focused episode from an independent prescribing journal on low ferritin with a normal hemoglobin.

  • 2026 ASH Clinical Practice Guidelines | Iron Deficiency Anemia

    American Society of HematologyOpen on YouTube

    The society behind the 2026 guideline explains the new ferritin thresholds for diagnosing iron deficiency.

  • Mayo Clinic: William Palmer, M.D. - Hereditary Hemochromatosis

    Mayo ClinicOpen on YouTube

    A Mayo Clinic hepatologist covers the inherited cause of true iron overload and how high ferritin leads to the diagnosis.

  • Mayo Clinic Minute: Female athletes may need more iron

    Mayo ClinicOpen on YouTube

    A short explainer on why training women are at higher risk of low iron stores.

Protocols that act on Ferritin

Common questions

Is ferritin the same as iron?

No. Ferritin is the protein that stores iron, and the test estimates how much is in storage. Serum iron measures iron moving in the blood right now, which swings with meals and time of day. See ferritin vs iron.

What does ferritin do in the body?

Ferritin stores iron inside cells in a safe mineral form and releases it when the body needs it, for example to make hemoglobin. Each molecule can hold up to about 4,500 iron atoms [9].

Is ferritin included in a CBC?

No. A complete blood count measures hemoglobin and red cell size but not ferritin. Ferritin is ordered separately or as part of an iron panel with serum iron, TIBC and transferrin saturation.

Can ferritin be low when hemoglobin is normal?

Yes. Stores run down before anemia appears, so iron deficiency can exist with a normal hemoglobin [18]. The ASH 2026 thresholds apply with or without anemia [4].

Is ferritin an acute phase reactant?

Yes. Ferritin rises during infection, injury and inflammation regardless of iron stores, which is why it is read alongside CRP [5].

Does ferritin drop during your period?

One period does not move ferritin much day to day, but regular menstrual blood loss is the most common cause of low iron stores in premenopausal women [26]. Heavy menstrual bleeding is one reason ASH suggests a higher threshold of up to 50 ng/mL [4].

What is a dangerously low ferritin level?

There is no single danger number. Below 15 ng/mL means stores are empty [1], and single-digit results usually come with anemia or will soon. Any low result needs a clinician to find the cause, especially in men and after menopause.

Should I take iron if my ferritin is low?

Only after a clinician has confirmed iron deficiency and looked for the cause. Low ferritin in men and postmenopausal women often needs gut investigation [1], and iron supplements cause gut side effects in many people [41].

What is ferritin face?

"Ferritin face" is a social media term for a tired, pale look that people link to low iron. It is not a medical diagnosis. Pallor can come with anemia, but a blood test, not a face, shows whether iron is low.

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