7 reasons why your ferritin isn't improving

7 reasons why your ferritin isn't improving

More than 1 billion people worldwide are suffering from iron deficiency. And despite supplementing, so many people are finding their iron status doesn’t shift, or only moves very slowly over months and months.

As a naturopath, the main deficiency I see in my clients is iron-deficiency. And a large portion of my clients have been dealing with iron-deficiency for months or years, despite supplementing for most of this time.

So the question that many ask us is: “I’m taking iron supplements, so why isn’t my iron levels coming up?”

And there is a lot to explore within iron supplementing, it’s not just as simple as going to the chemist and grabbing the first iron supplement you see.

Let's explore all the possibly reasons why your iron levels are not coming up despite supplementing...

  1. The first reason - the form of iron you are taking has low absorption. The type of iron matters, some have a low absorption rate (like ferrous sulphate), some are highly absorbed (like iron bisglycinate).

Ferrous bisglycinate has a bioavailability of 2 to 4 times more compared to ferrous sulphate! In clinical trials, only those treated with ferrous bisglycinate had significant changes in ferritin levels compared to those taking ferrous sulphate.

Ferrous sulphate, found in most chemist brands, has also been shown in research to irritate the stomach lining, causing gastrointestinal side effects such as cramping, nausea and constipation which may also contribute to colonisation of pathogens and changes in your gut flora profile.

  1. You are taking it with other products that are hindering absorption - like calcium supplements, turmeric, dairy products, zinc, caffeine, black tea which have all been shown to potentially impact absorption of iron in your gut. Ideally, you should be taking your iron supplement away from all other supplements, I find the best time can be after dinner.
  2. Hepcidin levels - Hepcidin, is the master regulator of systemic iron. It is a protein made by your liver, that makes sure you don’t overdose on iron which would be very toxic. Humans and other mammals lack effective mechanisms to excrete excess iron, and therefore the sole means of maintaining iron balance is by regulating intestinal iron absorption to match systemic iron requirements.

How does hepcidin regulate iron levels?

High hepcidin levels block intestinal iron absorption. Dietary iron is absorbed predominantly in the duodenum (gut). Hepcidin reduces the iron entry to our blood from the absorptive duodenal cells. Absorption increases in response to increased iron requirements like iron deficiency or anaemia.

So if you are iron-deficient, or anaemic, hepcidin levels will naturally go lower so you get more iron from your diet/supplements, in comparison to someone's hepcidin levels if they had very high iron levels. 

Hepcidin also increases when in an inflammatory state, or infection state. 

Hepcidin synthesis is greatly increased during inflammation, autoimmune diseases, chronic infections, which means in these states a person will struggle to get the adequate amount of iron from their diet or supplements, and majority will be iron-deficient or anaemic. In these cases, we need to treat the inflammation levels to lower the hepcidin. Not just give them more and more iron, because this would worsen their hepcidin levels. 

Research shows that higher dose iron supplements at doses of 60 mg Fe or higher increase hepcidin for up to 24-48 hours and are associated with lower iron absorption on the following day. A study completed showed an oral dose of 65 mg of iron in healthy volunteers caused a 5-fold increase in hepcidin within 1 day!

This shows, that with increasing dose of iron, absorption of iron decreased. This is an interesting find, as people usually think taking more iron, is better. 

The duration of the hepcidin response – lasting around 48 hours - supports alternate day supplementation. So if we skip every second day, we are allowing our hepcidin to naturally go back down, so we maximise absorption from our supplement.

  1. Your output of iron is too high - like your periods are heavy, or you have internal blood loss. This is something to chat to your doctor about.
  2. Gut absorption issues – iron absorbs within the duodenum (gut) so when our gut lining is inflamed, or damaged such as  in cases of IBS, food intolerances, low stomach acid production, IBD, coeliac disease – you will have trouble in absorbing the maximum amount of iron.
  3. Your thyroid is underactive. It's well established that if you have hypothyroidism or hashimoto's, you will struggle to increase your iron levels. There is a unique pathological dance between the two. reduced T3 levels in hypothyroidism down-regulates ‘iron-regulatory-protein’ which slows down the production of ferritin by the liver. So your ferritin levels may not budge on blood tests.
  4. You have a deficiency of copper or Vitamin A. Copper is required for the transport of iron, and storing process in the liver. When copper levels are low, the body may absorb less iron. You can check your copper levels on a blood test to be certain. Vitamin A plays a role with increasing iron absorption and modulation of erythropoiesis. 

And of course, before implementing any new vitamins or changes to your health, ensure you check in with your medical professional.


. Kortman GAM, Boleij A, Swinkels DW, et al. Iron availability increases the pathogenic potential of Salmonella typhimurium and other enteric pathogens at the intestinal epithelial interface. PLoS One 2012;7:e29968.

- Hallberg L, Ryttinger L, Sölvell L. Side-Effects of oral iron therapy. A double-blind study of different iron compounds in tablet form. Acta Med Scand Suppl 1966;459:3–10.

- Pineda O, Ashmead HD. Effectiveness of treatment of iron-deficiency anemia in infants and young children with ferrous bis-glycinate chelate. Nutrition 2001;17:381–4.

- Bovell-Benjamin AC, Viteri FE, Allen LH. Iron absorption from ferrous bisglycinate and ferric trisglycinate in whole maize is regulated by iron status. Am J Clin Nutr 2000;71:1563–9.

- Duque X, Martinez H, Vilchis-Gil J, et al. Effect of supplementation with ferrous sulfate or iron bis-glycinate chelate on ferritin concentration in Mexican schoolchildren: a randomized controlled trial. Nutr J 2014;13:71.

- Bagna R, Spada E, Mazzone R, et al. Iron supplementation with iron sulfate versus iron bisglycinate chelate in preterm newborns. Curr Pediatr Rev 2018;14:123–9.

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