01/13/2026
If you have an iron problem, chances are you have a thyroid problem.
In fact, when creating our thyroid course, I came across several studies that showed taking thyroid medication corrected anemia & ferritin. Thyroid hormone has hematologic effects in iron-deficient subclinical hypothyroid patients. In randomized controlled studies, it has been found that adding levothyroxine to a regime of supplemental iron significantly improved hemoglobin, red cell count, and ferritin compared to those who took iron alone, who often showed no improvements or got worse.
There’s a reason for this, and it’s very important to understand since iron is useless without metabolic demand.
T3 is the true thyroid hormone and it is what determines mitochondrial respiration rate, ATP supply and demand, and signals cells to build heme enzymes.
Without T3, iron has nowhere to go.
T3 upregulates iron-dependent enzymes and directly increases transcription of the Cytochromes (a, b, c), and heme-iron proteins in the electron transport chain. It also regulates catalase, peroxidases, and succinate dehydrogenase.
Therefore, if T3 is low (as it is in people with hypothyroidism, and those misdiagnosed who actually have hypothyroidism), then these enzymes are down regulated, causing iron to NOT be incorporated, and accumulates in serum or storage instead.
Therefore, thyroid function is senior to iron metabolism. In other words, iron use follows T3 signaling - not the other way around.
T3 only increases ferritin synthesis only when safe to do so. Ferritin is not passive storage, it is actively regulated. T3 will increase ferritin gene transcription but only when oxidative stress is low and when iron can be safely mineralized inside ferritin.
This is why you’ll likely always find hypothyroidism behind ferritin and iron issues. In hypothyroidism, ferritin synthesis is suppressed, or ferritin rises as an inflammatory protein (iron trapped).
This is why you will see both:
Low ferritin and high saturation and High ferritin and low saturation - they’re both hypothyroid patterns.
If you have issues, check your pulse and body temp upon rising, check LDL cholesterol & prolactin.