What’s The Forgotten Lab Marker When Assessing Thyroid Function and Inflammation?

Forgotten Lab Marker When Assessing Thyroid Function and Inflammation that you’ve probably never heard about. And neither has your doctor, at least in relation to thyroid status.

Scratching your head about why you can’t lose weight, are tired all the time, experiencing infertility and have all the signs of hypothyroidism, even though your thyroid tests including, TSH, Free T4 and Free T3 levels are in the OPTIMAL range? (Notice I didn’t say ‘Normal’ ranges which are different). 

Well, undetected iron anemia can mimic signs of low thyroid and affect how well your thyroid hormones are binding to and working in your cells. And Ferritin beautifully reflects your iron status, as it’s the storage form of iron. If it’s low, there’s a good chance you have iron anemia even if your RBC, hemoglobin, and iron levels look normal. Most doctors will not test or request an iron panel or ferritin if your RBC and hemoglobin levels look normal. That means low iron status and anemia often go undetected.

So let’s take a closer look at Ferritin

What are the symptoms of low ferritin?

  • Weakness
  • Fatigue
  • Difficulty concentrating
  • Poor work productivity
  • Cold hands and feet
  • Poor short-term memory
  • Lump in throat
  • Difficulty remembering names
  • Dizziness
  • Pounding in the ears
  • Difficulty Sleeping
  • Shortness of breath
  • Brittle nails
  • Headaches
  • Restless legs
  • Weight gain
  • Tinnitus

Do any of these sound familiar to you? The above symptoms overlap with Hashimoto’s disease and hypothyroidism so it can be difficult to ascertain whether it’s hypothyroidism or iron deficiency causing the symptoms.

“Hypothyroidism based on symptoms is indistinguishable from iron deficiency,” states Dr. Esa Soppi of Finland.

What causes iron deficiency and low ferritin?

  • Heavy menstrual bleeding
  • Blood donations (allow 3 weeks to test ferritin after blood donation)
  • Pregnancies
  • Surgeries
  • Accidents
  • Inadequate stomach acid
  • Antacid medications
  • Celiac disease
  • Gut problems causing malabsorption of nutrients 
  • High-level athlete 
  • Vegan/vegetarian
  • Internal bleeding

These all lead to either loss or poor absorption of iron, or inadequate intake leading to low ferritin levels.

I think most people associate iron anemia with women and while it’s estimated that 10-20% of menstruating women are iron deficient, this list illuminates how men can also suffer from anemia.

What are optimal ferritin levels for thyroid health?

Once ferritin gets below 30, an iron deficiency may be indicated despite the fact the lower end of the laboratory cut-off range is usually 10-20. Interestingly enough, ferritin levels can be normal, around 50-100, and a person may still be iron deficient for them, especially if there is what we call, subclinical hypothyroidism occurring. This can make the diagnosis somewhat tricky. 

According to Dr. Esa Soppi of the Eira Hospital in Helsinki, Finland, optimal ferritin levels for hypothyroidism are >100 and iron therapy should be continued until symptoms have resolved. He also recommends that the ferritin level should be checked regularly to be sure the levels stay optimal. 

He also states that if someone has restless leg syndrome (RLS) and their ferritin is <75, then they should be considered iron deficient. (A side note here, also consider magnesium and omega 3 levels with RLS).

Many clients with Hashimoto’s disease and hypothyroidism, start to feel worse when their ferritin drops below 80 and usually there is hair loss when it drops below 50, yet they are still within the normal lab ranges.

Why is iron so important for the thyroid?

Iron is required for the production of the thyroid hormones T4 and T3 in the thyroid gland, the conversion of T4 into the more active T3, and iron is required for the utilization of T3 inside the cell. You can see how devastating low iron stores can be on thyroid hormone status as it affects the production, conversion, and utilization.

Even if the TSH, Free T4, and Free T3 all look normal, low iron stores will impair utilization of thyroid hormone in the cell at the receptor level thus creating a picture that all your numbers are normal but you still don’t feel well. Low ferritin levels can also increase the production of reverse T3 which is the inactive form of T3 that binds to T3 receptors thus blocking T3 from binding. This is one reason I like to see reverse T3 tested.

Low ferritin levels can increase TSH levels which gives the picture of hypothyroidism but it is really just low ferritin levels.

The Goldilocks Effect…

You can either have too much iron, too little or just the right balance in your body and the ferritin test can give us an excellent picture of how much iron is actually stored in your body, in your tissues.  

Too little thyroid hormone can lower ferritin levels and too much thyroid hormone such as in Graves’ disease will increase ferritin levels sometimes above normal.

Reasons for elevated ferritin include inflammation, infection, and exposure to large amounts of iron such as from well water, iron cookware, or supplements.

I see great results in clients when we balance iron and ferritin levels. Some clients end up requiring much less thyroid hormone or none at all once their iron and ferritin levels are in the optimal range for them and that can vary from person to person.

This is one test you don’t want to miss if you have Hashimoto’s disease and/or hypothyroidism.

Let’s talk about men and iron for a second.

Since men do not have a menstrual cycle, they are the most at risk for accumulating iron.  As iron builds-up in a man’s body he may develop the following symptoms as it accumulates in the brain and other body tissues.

  • Brain fog
  • Fatigue
  • Low sex drive and erectile dysfunction (iron accumulates in the testicles)
  • Mood swings, especially anger
  • Digestive problems as iron builds-up in the gut
  • Anxiety
  • Depression
  • Fatigue after meals (insulin resistance)
  • Memory loss
  • Joint pain
  • Weight loss
  • Abdominal pain
  • Hair loss
  • Congestive heart failure

Iron is extremely “heavy” in the bloodstream so it forces the heart to work harder as it pumps this heavy metal through your blood vessels resulting in blood pressure changes and more inflammation in your arteries.

This is where the ferritin test is so important because it can tell us if there is too much or too little iron in your body.  It’s a simple blood test but rarely ordered during general check-ups and standard blood panels. I believe it is one of the most important and overlooked tests in medicine today.  This is why I’ve started to include it as part of my recommended blood panel.

Are there other tests you should have? Yes

To get a more accurate picture, the labs below along with ferritin are valuable.

  • Serum Iron
  • % iron saturation
  • TIBC (Total iron binding capacity)

If you only check ferritin without the above three markers then you’re not getting the complete picture.  If the above markers are elevated along with a normal or low ferritin, then it most likely isn’t a good idea to supplement with iron and we need to know this.

If the above three are elevated but ferritin is low, then your blood and cells are saturated with iron and it isn’t being used properly by your body.  This could be due to liver dysfunction, hypothyroidism, B12, or folate deficiency.  You don’t want to dump more iron into a system that is already saturated.

If however the % iron saturation and TIBC are low and your serum iron is normal or low along with a low ferritin, then it can be safe to start supplementing with iron.  Have these levels checked about every 8-12 weeks until all your markers normalize.

The ferritin test is by far one of the most important tests you can have done on a regular basis yet it is almost never ordered by conventional doctors.

What is a healthy-optimal ferritin range?

Women: 70-150 ng/ml

Men: 80-300 ng/ml

You can order your thyroid panel and ferritin/iron panel from my affiliate lab HERE

I know this one was long but I hope it was helpful!


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