Can Athletes Take Iron Supplements for Better Performance?

November 27, 2025 •

4 min read

According to the National Institutes of Health, iron deficiency is common among athletes, particularly females and endurance athletes. This makes many wonder: can athletes take iron supplements to improve their performance? The answer is nuanced and depends heavily on an individual's iron status and needs.

Quick Summary

This guide provides crucial information for athletes regarding iron supplementation, including who is at risk for deficiency, the potential benefits, and the significant risks of taking supplements without a diagnosis.

Key Points

Blood Test First: Never start iron supplements without a blood test to confirm a deficiency, as excess iron can be harmful.
High-Risk Athletes: Endurance athletes, female athletes, and vegetarians are at a higher risk for iron deficiency due to training demands and dietary factors.
Performance Impact: Iron deficiency can cause fatigue and reduced endurance by impairing oxygen transport to muscles.
Supplement Benefits: For diagnosed deficiencies, iron supplements can restore iron levels and alleviate performance-sapping symptoms like fatigue.
Risks of Excess Iron: Unnecessary supplementation can lead to iron overload, organ damage, and increased oxidative stress.
Professional Guidance: Always consult a healthcare provider or sports dietitian for proper diagnosis, dosage, and monitoring.
Dietary Strategies: Prioritize iron-rich foods and use dietary strategies, like pairing non-heme iron with Vitamin C, to optimize absorption.

Why Athletes Are at a Higher Risk for Iron Deficiency

Athletes, especially those involved in endurance sports like running and cycling, face unique challenges that increase their risk of developing iron deficiency.

Exercise-induced hemolysis: High-impact activities, such as running, can cause a small but significant destruction of red blood cells in the feet, a process known as mechanical hemolysis.
Sweat loss: Intense training leads to significant sweating, and sweat contains small amounts of iron. While the amount is minimal per session, cumulative losses over time can impact an athlete's iron balance.
Gastrointestinal blood loss: Strenuous exercise can cause minor gastrointestinal bleeding, further contributing to iron loss.
Increased iron demand: The body's increased need for oxygen transport and red blood cell production during intense training elevates the overall demand for iron.
Inadequate dietary intake: Athletes, especially those following vegetarian or vegan diets, may not consume enough iron from their food, leading to a negative iron balance.

The Role of Iron and Performance

Iron is a vital component of hemoglobin, the protein in red blood cells that transports oxygen from the lungs to the muscles. It is also crucial for energy metabolism and numerous other cellular functions. An iron deficiency can severely compromise an athlete's physical capacity due to reduced oxygen delivery, leading to fatigue, reduced endurance, and overall decreased performance. Even non-anemic iron depletion, where ferritin levels are low but hemoglobin is still normal, can negatively affect athletic performance and increase feelings of fatigue.

Can Athletes Benefit from Iron Supplements?

For athletes diagnosed with an iron deficiency, supplementation can be highly beneficial. It can help restore iron stores, improve hemoglobin levels, and alleviate symptoms like fatigue, ultimately enhancing exercise capacity. Several studies have shown improvements in fatigue and mood states in iron-depleted, non-anemic athletes following iron supplementation. However, the benefit is most significant in those who are genuinely deficient.

For athletes with sufficient iron stores, the evidence for performance enhancement from iron supplementation is inconsistent at best. Unnecessary supplementation can be counterproductive and even dangerous.

Oral vs. Intravenous Iron Supplementation

Depending on the severity of the deficiency and an athlete's tolerance, iron can be supplemented orally or intravenously.

Oral Iron Supplements

Oral supplements are the most common form of treatment for iron deficiency.

Pros:

Widely available and inexpensive.
Permitted for use under anti-doping regulations.
Effective for correcting mild to moderate deficiencies over time.

Cons:

Can cause gastrointestinal side effects like constipation, nausea, and abdominal pain.
Absorption can be inhibited by certain foods and beverages like coffee, tea, and calcium.
May elevate hepcidin levels, a hormone that regulates iron absorption, potentially reducing the effectiveness of supplementation.

Intravenous (IV) Iron

Intravenous iron is typically reserved for severe deficiencies, cases of poor oral absorption, or when rapid restoration is needed.

Pros:

Bypasses the digestive tract, avoiding gastrointestinal side effects.
Quickly restores iron stores and hemoglobin levels.
More reliable absorption compared to oral supplements.

Cons:

More invasive and requires administration by a healthcare professional.
Risk of serious side effects, though rare, such as allergic reactions.
For anti-doping purposes, intravenous infusions exceeding 100 mL within a 12-hour period are prohibited without a Therapeutic Use Exemption (TUE), though this is only relevant for infusions containing prohibited substances.


Feature	Oral Iron Supplementation	Intravenous (IV) Iron
Administration	Oral pills, liquids, or chews	Requires medical professional and IV infusion
Effectiveness Speed	Slower; takes weeks to months	Much faster, can restore iron levels quickly
Side Effects	High risk of gastrointestinal issues	Low risk of GI side effects; potential for rare severe reactions
Monitoring	Less intensive; periodic blood tests	Close medical supervision needed during administration
Suitability	Mild to moderate deficiencies; general use	Severe deficiencies, intolerance to oral, or rapid restoration needed
Risk of Toxicity	Lower; depends on dosage and duration	Potentially higher with very large doses, but professionally managed

The Dangers of Uncontrolled Iron Supplementation

Taking iron supplements without a confirmed deficiency is not only unnecessary but can be dangerous.

Iron Overload (Hemochromatosis): Excessive iron can build up to toxic levels, damaging organs like the liver, heart, and pancreas. Individuals with the genetic condition hemochromatosis are at a higher risk.
Oxidative Stress: Unbound, or "free," iron can increase oxidative stress during exercise, causing cellular damage and potentially hindering performance rather than helping it.
Masking Underlying Issues: Taking iron without a diagnosis can mask other health problems that share similar symptoms, like chronic fatigue or other nutritional deficiencies.

How Athletes Should Approach Iron Supplementation

The decision to start iron supplementation should never be taken lightly. The correct approach involves careful monitoring and professional guidance.

Get a Blood Test: The first and most crucial step is to get a blood test that measures iron status markers like serum ferritin and hemoglobin. This provides a clear picture of whether a deficiency exists.
Consult a Professional: Always work with a healthcare provider or a sports dietitian. They can interpret test results, determine the cause of any deficiency, and recommend the appropriate type and dosage of supplementation.
Start with Diet: For mild deficiencies or prevention, focusing on a diet rich in iron is the first line of defense. Incorporate heme iron sources like red meat and poultry, and enhance non-heme iron absorption from plant sources like beans and spinach by pairing them with Vitamin C.
Monitor Regularly: Iron levels should be re-tested periodically, typically every 6-8 weeks during supplementation, to track progress and prevent over-supplementation.

For additional guidance on sports nutrition, the National Academy of Sports Medicine (NASM) offers valuable resources.

Conclusion

In summary, while iron is crucial for athletic performance, the answer to whether an athlete can take iron supplements is not a simple 'yes' or 'no.' For those with a diagnosed iron deficiency, supplementation can significantly improve health and athletic performance. However, for those with sufficient iron, the risks of unnecessary supplementation outweigh any potential, and unproven, benefits. The correct path involves professional medical assessment to determine individual needs, ensuring safe and effective management of iron levels.

Frequently Asked Questions

Female athletes (due to menstruation), endurance athletes (e.g., runners, cyclists), adolescent athletes experiencing growth spurts, and vegetarian or vegan athletes are at a higher risk for iron deficiency.

Common symptoms include unusual fatigue, decreased endurance, shortness of breath during exercise, and poor athletic performance.

No, it is not recommended. If you have sufficient iron stores, taking extra iron is unlikely to boost performance and carries a risk of iron overload, which can be toxic and damaging to your organs.

Athletes can increase iron intake by consuming heme iron from red meat, poultry, and fish, and non-heme iron from sources like fortified cereals, beans, lentils, and spinach. Pairing non-heme iron with a source of Vitamin C aids absorption.

Oral iron is taken via pills or liquid and is used for mild to moderate deficiencies, but can cause digestive issues. Intravenous (IV) iron is administered directly into the bloodstream by a medical professional for severe deficiencies or when oral supplements are ineffective.

Oral iron pills, chews, and liquids are permitted in sport. Intravenous iron infusions of 100 mL or less within a 12-hour period are also permitted, but larger infusions require a Therapeutic Use Exemption.

Ferritin is a protein that stores iron in your body. For athletes, low ferritin levels can indicate depleted iron stores, even if hemoglobin levels are still normal. Monitoring ferritin is a key way to assess iron status before a full-blown deficiency develops.

Athletes at high risk for iron deficiency should get their iron status (including serum ferritin) checked periodically, often every 6-12 months, or as recommended by a healthcare professional, especially during periods of intense training or competition.