Ferritin 101: what your body is trying to tell you

Iron is a crucial nutrient needed to make hemoglobin-a protein in red blood cells that carries oxygen around your body. It’s also vital for ATP(energy), hormones and neurotransmitters. Iron needs to be available, able to be transported, absorbed and recycled correctly.  It is important to always get a full iron panel test, one marker does not tell you the whole story.

 

What is ferritin?

Ferritin is your body’s iron storage. Think of it like your pantry. Iron circulates for your body to use immediately and it also stashes some away for “in case”.

 

Quick symptoms of low ferritin:

• Fatigue
• exercise intolerance (and even walking up stairs can leave you breathless)
• restless legs
• brain fog, confusion, depression, mood issues
• hair shedding

 

Your Iron panel test includes:

• Iron : Tells you how much iron is circulating in your blood
• Ferritin:is your iron storage. Low can indicate deficiency and high can indicate inflammation/overload
• TSAT: the percentage of iron binding sites on transferrin that is occupied
• TIBC: measures your body’s capacity to bind iron with transferrin

Your CBC (complete or full blood count) Test:

• Hemoglobin: oxygen carrying protein in red blood cells
• Hematocrit : % of red blood cells to the total blood volume
• MCV: average rbc
• MCH: hemoglobin/rbc
• MCHC: concentration of hb in rbc
• RDW: variation of rbc

 

Why Folate and B12 matter:

Folate and B12 are also needed to make red blood cells, so they should be taken into account when looking at Complete Blood Count because deficiencies can cause anemia. Iron, Folate and B12 deficiencies can occur together which can alter a CBC. 

 

When ferritin is high:

Ferritin is an acute-phase inflammatory reactant. A high reading over 110ng/mL can mean there is oxidative stress. The full iron panel needs to be taken into consideration when looking at this possibility. 

For example: High ferritin + low/normal saturation can mean inflammation. But a high ferritin + high saturation could indicate iron overload such as genetic hemachromatosis. 

For Inflammation test: CRP/ESR, metabolic: liver, kidney, full cholesterol and insulin, viral load, pathogens, hepcidin, CBC, homocysteine, copper

For Iron Overload: Genetic testing for hemachromatosis. 

 

When ferritin is low:

Iron deficiency with or without anemia needs evaluation before supplements should be considered. Why? Because The root cause matters. Questions to ask:

• Blood loss from heavy menstruation?
• Gut: Poor absorption from Celiac, SIBO, H.pylori, low stomach acid
• Hepcidin: the gatekeeper. It can block iron from being absorbed and can trap stored iron.
• Stress: stress creates cortisol, suppresses stomach acid and can cause leaky gut.
• Diet: What you eat and when you eat matter.  Non-heme and heme sources of iron. Caffeine and calcium block iron absorption. Iron needs vitamin C to absorb. 

Treating low iron depends on the root cause. Dosage, timing and form of iron matter. There are many cofactors needed in order for iron to be absorbed and used correctly. New research shows a new form of iron called sucrosomial iron to be superior. 

Tests to consider with low ferritin: Vitamin D, copper, celiac, SIBO, H.pylori, stomach acid and thyroid panel.

An iron deficiency can take about 3 months with consistent intake to correct. (after everything else has been ruled out/fixed). I saw my ferritin go up from 25 ng/ml to 30 ng/ml in just 5 weeks with taking sucrosomial iron with vitamin C (brand is SIDERAL Forte 15), and taking my iron at night away from food, caffeine and other supplements. I have had low ferritin most of my life. Levels have been anything from 9 to 25. Once it was 43 briefly for a few months before dropping again to the 20’s.  This is partly due to long term damage to my intestine from celiac disease, but also due to taking the incorrect form in the past. Now I take sucrosomial iron which bypasses stomach acid and makes it to the part of the intestine where it is then able to be absorbed. I also make sure I eat a diet high in both heme and non-heme iron with vitamin C pairing and avoid caffeine, calcium, phytates when eating iron.  You can achieve better ferritin levels even with Celiac disease. 

A note: never take high dose iron or high dose vitamin C as iron is also food for certain pathogens that feed on it and this can create an imbalance in your gut microbiome and lead to acid reflux and other unpleasant symptoms. The key is low dosage over a consistent time with the right cofactors and a healthy diet. (see my iron post for more details below).

 

New Ferritin 2026 Guidelines:

The American society of hematology has new guidelines for diagnosing of iron deficiency. In short anything  30ng/mL and under for most adults is now considered a deficiency. 

Children: 9 months-4yrs <20ng/mL

Teens/ adults:<30 ng/mL

Teens/adults: (non menstruating/and menstruating)<30 ng/mL

Heavy bleeders/Additional risk factors, planning pregnancy/ongoing iron deficiency: <50ng/mL

Pregnancy: <30 ng/mL

To learn more about iron deficiency please see my article on Iron deficiency .

 

References:

1. Yilmaz B, Li H. Gut Microbiota and Iron: The Crucial Actors in Health and Disease. Pharmaceuticals (Basel). 2018 Oct 5;11(4):98. doi: 10.3390/ph11040098. PMID: 30301142; PMCID: PMC6315993. The Effect of iron on gut microbiota and pathogens 
2. “Supplementing with high doses of iron (>100 mg/day) was linked to alterations in the gut microbiota, marked by a decrease in certain beneficial bacterial strains associated with gastrointestinal health, alongside a concurrent rise in those associated with inflammatory reactions.” Shearer J, Shah S, MacInnis MJ, Shen-Tu G, Mu C. Dose-Responsive Effects of Iron Supplementation on the Gut Microbiota in Middle-Aged Women. Nutrients. 2024 Mar 10;16(6):786. doi: 10.3390/nu16060786. PMID: 38542697; PMCID: PMC10975138.
3. “Elevated iron intake (>100 mg) was associated with an augmentation of Proteobacteria and a reduction in various taxa, including Akkermansia, Butyricicoccus, Verrucomicrobia, Ruminococcus, Alistipes, and Faecalibacterium.”Shearer J, Shah S, MacInnis MJ, Shen-Tu G, Mu C. Dose-Responsive Effects of Iron Supplementation on the Gut Microbiota in Middle-Aged Women. Nutrients. 2024 Mar 10;16(6):786. doi: 10.3390/nu16060786. PMID: 38542697; PMCID: PMC10975138.
4. Gómez-Ramírez S, Brilli E, Tarantino G, Girelli D, Muñoz M. Sucrosomial^® Iron: An Updated Review of Its Clinical Efficacy for the Treatment of Iron Deficiency. Pharmaceuticals (Basel). 2023 Jun 6;16(6):847. doi: 10.3390/ph16060847. PMID: 37375794; PMCID: PMC10305423.
5. New 2026 guidelines for ferritin: https://www.sciencedirect.com/science/article/pii/S2473952926006038