The Best 9 Iron Supplements, According to Dietitians

Iron is the most common mineral deficiency worldwide. People with heavy menstrual periods, frequent blood donors, those with cancer or gastrointestinal disorders, pregnant people, preterm infants, and those with a limited diet can all be at a higher risk of iron deficiency and may benefit from an iron supplement.

To create a list of the best iron supplements, we researched dozens of them and spoke with experts to learn their considerations for taking one. We reviewed research on the various forms of iron and appropriate dosing, prioritizing brands with third-party testing, minimal added ingredients, and proper doses.

Benefits of an Iron Supplement

Taking an iron supplement can help correct or prevent an iron deficiency. If you are deficient in iron, you can feel tired, have difficulty concentrating, feel weak, and have trouble concentrating. If you have these symptoms, it's important to consult a healthcare professional to get your iron levels tested to determine if low iron is the root cause of these symptoms. If so, taking an iron supplement at the right dose will be critical for correcting these symptoms.

An iron supplement can be helpful for people with higher iron needs, such as pregnant people, those with heavy periods, or frequent blood donors. Amanda Wagner, MEd, RDN, LDN says athletes tend to have high iron needs due to iron losses through sweat, foot strike hemolysis, or not getting enough iron in the diet. Endurance athletes—females in particular—may be at greater risk of iron deficiency, which can hinder performance. It is important to note, however, that iron supplementation will not improve your athletic performance if you are not low in iron.

If you don't eat enough iron from food sources, taking an iron supplement can help ensure you are getting enough and don't develop iron deficiency anemia. This can be particularly helpful for vegans and vegetarians, as the recommended amount of daily iron for vegetarians is 1.8 times higher than for those who eat meat.

What Registered Dietitians Want You To Know

• Types of iron: Iron supplements can have side effects. Iron bisglycinate is gentle on the stomach and less likely to cause issues such as constipation. Other forms of iron, like ferrous sulfate and ferrous fumarate, are not as gentle and may cause stomach issues for some.
• How to take:Jamie Gershel, MS, RD, says taking iron supplements on an empty stomach can enhance absorption. However, if this leads to stomach upset, you can take your supplement with food or immediately after. Wagner recommends taking iron supplements with vitamin C-rich foods. She also recommends taking them at least an hour and a half away from any wine, coffee, or tea, which can impact iron absorption. You should also take your iron supplements separately from calcium, zinc, and antacids, which can inhibit absorption.
  
• Seek a professional if: Iron supplements can interact with certain medications, such as levodopa and levothyroxine. If you take proton pump inhibitors, you may not respond well to iron supplements because they reduce the stomach acid needed for iron absorption. If you are taking any medication we recommend speaking with a healthcare provider before using iron supplements.

Editor's Note

Our team of registered dietitians reviews and evaluates every supplement we recommend according to our dietary supplement methodology. From there, a registered dietitian on our Medical Expert Board reviews each article for scientific accuracy. Always speak with a healthcare professional before adding a supplement to your routine to ensure it's appropriate for your needs and dosage.