Iron deficiency without anemia and iron infusions, rethought

You are functioning. But inside, it has gone quiet.

I bet you know this feeling.

You get up in the morning and ask yourself why, after eight hours of sleep, you feel as if you had never slept. Why you feel cold although the heating is on. Why during your coffee break you think you are about to fall asleep if you sit down. Why you have no strength left in the evening to meet friends. Why your hair looks different from how it did two years ago. Why your legs start to tingle in the evening as soon as you come to rest.

And you went to the doctor. Maybe even twice, three times, four times. They drew your blood. The doctor nodded. She said: everything is in the normal range. Maybe she added that you should take it a bit easier. Maybe a little less stress. Maybe psychotherapy. Maybe magnesium. Maybe "this will pass with time".

And you drove home. Somehow relieved that nothing was found. And somehow more frustrated than before. Because you know: there is more. Your body is talking. And you do not understand it, because the language in which you are speaking is rougher than what your body is telling you.

Not too little iron in the sense of a classical anemia. But something that, in German medicine, was for a long time hardly noticed and is still far too often overlooked today: functional iron deficiency without anemia.

This article is for you, if for months or years you have been trying to understand why something is missing that you cannot name. It is also for you if you already know that you have an iron deficiency and ask yourself why the tablets never work the way you wish. And it is for you, if you are wondering whether an iron infusion could make sense for you.

What iron really does for you, every day, without you noticing.

Imagine your system not as a "body", but as a city. In this city there are streets, transport routes, lights, factories, warehouses, post offices. The main currency in this city is not money. The main currency is oxygen. Without it, everything stands still.

And iron is the material from which the containers are built that transport oxygen. Imagine iron as the small trucks of your body. Without trucks, the goods stay in the harbor. The factories starve. The city becomes slower, quieter, paler.

Iron sits in your red blood cells, in hemoglobin, and brings oxygen from your lungs to every single cell. It sits in your muscles, in myoglobin. It is in hundreds of enzymes that pull energy from your food. It is part of the enzymes that sit in the mitochondria of every one of your cells, the small power plants.

Iron is also in the brain. Very prominently in fact. It is a cofactor in the production of dopamine and serotonin. It is involved in building the myelin sheath that wraps around your nerves.

Iron is involved with the thyroid. Thyroid peroxidase, a key enzyme that builds your thyroid hormones, needs iron as a heme cofactor. Iron is involved in the immune system. And iron is involved in heat regulation. That is why people with iron deficiency feel cold so often. It is not imagination. It is biochemistry.

Three words that confuse everything: hemoglobin, ferritin, reference range.

Hemoglobin: the red pigment that carries oxygen.

Hemoglobin is the protein that sits in your red blood cells and binds oxygen. When your hemoglobin drops, this has a name: anemia. The WHO defines this in women as hemoglobin under 12 grams per deciliter.

But: hemoglobin is the last bastion to fall. Your body holds hemoglobin at normal level for as long as possible, even when inside there has long been an alarm. When your hemoglobin falls, the barrel has been empty for months.

Ferritin: the warehouse no one looks at.

Ferritin is your iron storage. The central warehouse of your city. Ferritin falls long before hemoglobin falls. Ferritin is the early warning value.

The reference range: the biggest deception of everyday medicine.

A reference range is not a medical truth. It is a statistic. It describes how 95 percent of values in a studied population look. Typical ferritin reference range for women in German labs: 15 to 150 micrograms per liter. So a value of 18 will be printed as "within the normal range".

Several recent works show that symptoms can already arise at ferritin between 15 and 50 micrograms per liter. Some experts propose for symptomatic women a target range of 50 to 100 micrograms per liter.

What is functional iron deficiency really?

The term functional iron deficiency describes a state in which your body suffers from iron deficiency consequences, in which typical lab parameters point to a deficit, but in which hemoglobin has not yet fallen into the classical anemia zone. Several recent reviews estimate that iron deficiency without anemia is at least two to three times more common than classical iron deficiency anemia.

How does a functional iron deficiency really feel?

The quiet exhaustion that does not fit the stress.

"I am tired faster than I used to be, although I do not do more." Your mitochondria work with less iron than they need. You build the same energy currency, but at higher "cost".

The cognitive level: brain fog.

Your brain is a high-performance, hungry organ. Two percent of your body weight, but twenty percent of your oxygen consumption. Iron is a cofactor in dopamine production, serotonin production and myelination.

The cold. The hair. The thyroid.

Iron is involved in thermoregulation. It needs oxygen to produce heat.

Restless legs syndrome: when your legs do not come to rest at night.

RLS is a neurological condition in which a disturbed dopamine function in the brain plays a central role. Imaging studies with 7-Tesla MRI show in RLS patients reduced iron amounts in the substantia nigra, even when ferritin in the blood is normal.

The period. The thyroid. The mood.

A normal menstruation loses 15 to 20 milligrams of iron. A heavy one loses double to triple that. The enzyme thyroid peroxidase needs iron as a heme cofactor. The dopamine and serotonin system, which carries your mood, needs iron.

The hepcidin puzzle: why more iron often does not mean more effect.

Hepcidin is a hormone that your liver makes. A kind of doorman for iron. When hepcidin is high, the door closes. No matter how much iron you eat or swallow, it does not arrive.

1. When you have just received iron. After an oral tablet, hepcidin rises for up to 24 hours.
2. When you have a silent inflammation. Chronic processes keep hepcidin permanently elevated.
3. After strong physical exertion. Especially relevant for athletes.

The invisible scandal: why young women are so often overlooked.

Imagine a young woman. Mid-twenties, early thirties. She functions. But inside she is empty. She goes to the doctor. Hemoglobin: 12.3. Ferritin, if measured at all: 21. "All within the normal range."

That is the situation in which, statistically, every fifth young woman in Europe is or has been.

The tablet dead end.

Up to thirty percent of people who take oral iron report relevant gastrointestinal side effects. Many therefore drop out of therapy early.

A normal iron tablet delivers 40 to 100 milligrams of iron, of which 10 to 20 percent is absorbed (4 to 20 mg per day). A woman with a strong period loses 30 to 50 milligrams per cycle.

Iron infusions: old fears, new reality.

Today's preparations have almost nothing more in common with their predecessors from the 1970s. They are wrapped in stable carbohydrate cages, systematically tested in approval studies with thousands of patients.

Three advantages over tablets: independent of gut function, independent of hepcidin, storage is filled quickly. That does not mean every woman with low ferritin needs an infusion.

What the major studies really show.

Safety of modern iron infusions.

Hypophosphatemia

Ferric carboxymaltose can lead to a drop in blood phosphate. Mostly transient. With repeated high-dose administration, clinically relevant. With ferric derisomaltose the risk is markedly lower.

When I do not give an infusion

• No clear iron deficiency documented.
• Acute infection or high CRP.
• Severe kidney or liver disease.
• Oral therapy is functioning sufficiently.

The path in my practice.

The iron-deficiency lab

The seven doctors of lifestyle.

How does an iron infusion work?

The infusion is the beginning, not the end.

An infusion fills the tank. But if there is a hole in the tank, it will be empty again. My task is to find the hole.

My vision: medicine that one day no longer needs you.

Three basic principles:

Nutrition as foundation. Iron, protein, micronutrients. A plan that fits your everyday life.

Gut and absorption function. Even the best nutrition brings little if the gut cannot use it.

Lifestyle as therapy. When the seven doctors of lifestyle work together, you no longer need many therapies at all.

Your self-check.

Frequent questions, honestly answered.

Three concrete next steps.

You are not alone with what you feel. And you are not crazy because you know there is more. You are simply someone who does not look away. That is rare. And it is brave. And your body knows it. It will thank you.