Understanding Iron and Ferritin: The Energy Duo Your Body Can’t Thrive Without

What Iron and Ferritin Measure

Iron is a mineral your body uses to make hemoglobin — the protein in red blood cells that carries oxygen. No iron, no oxygen. And no oxygen means fatigue, brain fog, and that “I could sleep 10 hours and still feel tired” feeling.

Ferritin, on the other hand, measures how much iron your body has stored for later use. Think of ferritin like your savings account, while serum iron is your checking account. You can survive for a while on what’s in checking, but if savings are low, things go downhill fast.

Your doctor might also order TIBC (Total Iron-Binding Capacity) or Transferrin Saturation, which help show how efficiently your body is transporting iron. But ferritin is often the first clue when something’s off — especially in women.

Why Iron and Ferritin Matter

Iron is about so much more than anemia. When iron or ferritin levels drop, your cells can’t carry enough oxygen. That means every system — from your brain to your muscles to your thyroid — has to work harder just to keep up.

Low iron or ferritin can cause:

• Fatigue and low energy

• Brain fog or poor concentration

• Hair loss or brittle nails

• Feeling cold all the time

• Restless legs or poor sleep

• Shortness of breath during exercise

For women, low ferritin is especially common during heavy menstrual cycles, pregnancy, postpartum recovery, or thyroid dysfunction. Even mild depletion can tank your energy and slow metabolism.

On the flip side, too much iron can cause oxidative stress and damage organs — which is why balance (not “more is better”) is key.

Understanding Your Numbers

Typical reference ranges (may vary slightly by lab):

⚠️ Note: “Normal” doesn’t always mean “optimal.” Many functional medicine providers like to see ferritin around 50–100 ng/mL for ideal energy and hair growth.

Always discuss your numbers with your healthcare provider — especially before starting supplements.

Factors That Affect Iron and Ferritin

It’s not just diet — iron balance is influenced by multiple factors:

• Menstrual blood loss: Common cause of low ferritin in women.

• Digestive health: Low stomach acid or gut inflammation can impair absorption.

• Diet: Vegetarian or low-protein diets may reduce intake.

• Inflammation: Chronic inflammation can trap iron in storage, raising ferritin but lowering usable iron.

• Thyroid function: Hypothyroidism slows iron metabolism.

• Medications: Antacids and proton-pump inhibitors can reduce absorption.

Supporting Healthy Iron Levels

Here’s how I help my clients support better iron balance (without micromanaging every meal):

• Include heme iron sources: Lean red meat, poultry, and fish are absorbed best.

• Pair iron with vitamin C: Helps boost absorption (think spinach + strawberries).

• Avoid iron blockers with meals: Coffee, tea, and calcium can reduce absorption — separate them by a few hours.

• Support your gut: A healthy microbiome improves absorption efficiency.

• Watch inflammation: Addressing chronic stress and inflammation supports healthy ferritin use.

• Don’t over-supplement: Always test before adding iron — too much can be as harmful as too little.