Ferritin is one of the most confusing laboratory markers in functional and integrative medicine.
A ferritin of 35 might be called iron deficiency by one practitioner, completely normal by another, and "far too low" by someone else who wants it between 70 and 100.
So which is it?
In this episode of the Thyroid Answers Podcast, Dr. Eric Balcavage breaks down what ferritin actually tells us, why serum ferritin is not the same thing as stored iron, and why a ferritin number cannot be interpreted in isolation.
He explains how ferritin fits into the larger picture of iron physiology, including serum iron, transferrin saturation, TIBC, CBC markers, soluble transferrin receptor, reticulocyte hemoglobin, and inflammatory markers.
More importantly, he challenges the idea that there is one universally optimal ferritin range everyone should reach. A ferritin of 35 does not automatically mean iron deficiency, just as a ferritin of 70 or 100 does not automatically mean better health.
The goal is not to optimize ferritin. The goal is to understand the physiology behind the number.
In This Episode, We Cover:
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What ferritin actually is and how it stores iron inside cells
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The difference between intracellular ferritin and serum ferritin
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Why serum ferritin is an indirect marker rather than a direct measurement of stored iron
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Why a ferritin of 35 can mean very different things depending on the rest of the iron panel and the person's physiology
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Why ferritin increasing after iron supplementation does not prove that someone was iron deficient
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How inflammation and hepcidin can affect iron transport and availability
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The difference between true iron deficiency and inflammatory iron restriction
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Whether there is actually evidence for a universal "optimal" ferritin range of 70 to 100
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Why higher ferritin does not automatically mean healthier iron physiology
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How ferritin can be interpreted alongside CBC, serum iron, transferrin saturation, TIBC, soluble transferrin receptor, reticulocyte hemoglobin, and inflammatory markers
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Why the cause of iron deficiency matters just as much as replacing the iron
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Common causes of iron deficiency, including blood loss, inadequate intake, increased demand, and impaired absorption
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Why continually increasing iron can create problems when iron deficiency is not the actual issue
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What elevated ferritin may tell us about inflammation, iron loading, liver stress, metabolic dysfunction, infection, or cellular stress
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Why "appropriate" may be a better question than "optimal" when interpreting ferritin
The Bigger Picture
A laboratory value is not always the problem. Sometimes it is telling us a story about the person's physiology.
Ferritin is no different.
A ferritin of 35 does not automatically mean you need to take iron until you reach 70. A ferritin of 50 does not automatically need to become 80. And a ferritin of 100 does not automatically mean your iron physiology is healthier.
The better question is whether the ferritin makes sense in the context of the entire picture.
Before chasing a number, understand the physiology.
Work With Dr. Eric
If you're struggling with persistent thyroid symptoms, fatigue, poor recovery, or confusing lab patterns and want help figuring out what is actually driving the problem, schedule a discovery call at:
www.drericbalcavage.com
Get Dr. Eric's Book
If you haven't picked up a copy of Is This the Hill?, it is available in hardcover, paperback, and Kindle.
The premise of the book is simple: learn how to recognize when you're spending your time, energy, money, and emotion fighting the wrong battle.
Because chasing ferritin simply because someone told you it needs to be higher can absolutely become one of those hills.
