How to Treat Low Iron

First published October 2013
Updated August 2026

Iron deficiency is the most common nutritional deficiency in the world, but it continues to be underdiagnosed and undertreated, even in developed countries. While there are numerous causes of anemia, iron deficiency is the most common. As recently as 17 years ago, when I was in medical school, we were only taught about iron deficiency in the context of anemia.

The problem here is that iron deficiency causes so much more than anemia. Anemia is a LATE finding or iron deficiency. Anemia occurs when there are no iron stores left in the body, resulting in an inability to synthesize heme (an essential part of red blood cells).

What Can Low Iron Cause, Before Anemia?

When body iron stores are low, long before anemia develops, there are many other symptoms that can occur because iron is essential for so much more than just making red blood cells. There is a transferrin receptor (the protein that transports iron into a cell) on nearly every human tissue. Thus, iron deficiency without anemia can cause many symptoms, including but not limited to:

• fatigue
• dizziness
• headaches
• poor concentration
• hair loss
• shortness of breath
• exercise intolerance
• poor sleep
• restless leg syndrome

Iron is needed for the synthesis of important neurotransmitters like dopamine, serotonin, and norepinephrine.

How Is Low Iron Treated?

So how do we treat iron deficiency with and without anemia? Firstly, it needs to be diagnosed. This requires dedicated iron studies. Simply testing blood counts (CBC) to test for anemia is not enough. Ferritin is the most reliable test for iron deficiency. A low ferritin always means iron deficiency. Ferritin can be falsely normal/false high when someone is ill, injured, or inflamed. For that reason, other iron studies like serum iron, total iron binding capacity, transferrin, and transferrin/iron saturation are also useful for diagnosis.

Treatment starts with iron supplements in tablet, capsule or liquid form. Dietary changes are also important, but diet changes alone cannot correct iron deficiency in a timely fashion: a dedicated supplement is needed. Iron comes with side effects when taken orally (by mouth), so finding the right supplement can be challenging.

Iron salts like ferrous sulphate, ferrous fumarate and ferrous gluconate are the most effective of the oral options, but they taste bad and can have intolerable side effects, especially gastrointestinal.

Polysaccharide, glycinate and sucrosomial oral iron products are perfectly reasonable options if you cannot tolerate iron salts. Intravenous iron is a safe and very effective option when oral iron is not effective or tolerated.

At Nationwide Children’s, our Iron Disorders Program administers iron intravenously (via IV) to over 2000 patients per year, so you can ask your primary care physician about a referral to our program for intravenous iron if oral iron did not work for you or your child.