The Ferritin Factor: Is Low Ferritin affecting your performance?
Ferritin is your body’s main storage form of iron.
As a Sports Dietitian, one of the most important lab markers I monitor in athletes—especially female athletes and endurance athletes—is ferritin. But what exactly is ferritin, and why should you care about it?
Ferritin is found in serum as a protein and releases iron when your body is in need of it. Iron is needed to provide oxygen and energy to your the body. It also plays a large role in the immune system, hormone synthesis, and muscle function. You can think of it like your iron “savings account.” While iron travels through your bloodstream doing important jobs like helping red blood cells carry oxygen, ferritin is what your body taps into when iron levels start to dip.
A ferritin blood test tells us how much iron you have in reserve—not just what’s circulating at that moment.
Is low ferritin common?
It is estimated that over 50% of endurance athletes have low ferritin levels due to high iron demands. Iron is lost in sweat, urine, the GI tract, and during the menstrual cycle. Chronic use of anti-inflammatory drugs (i.e., Advil, Motrin, Aleve) and breakdown of red blood cells from repeated foot striking on the ground can also increase iron losses. With increased losses and low intake and absorption of iron, storage of iron in the blood decreases.
Common symptoms of low ferritin include:
Lethargy/fatigue
Low mood
Pale skin
Increased heart rate
Dizziness
Difficulty concentrating
Decreased performance
Increased perceived effort
Difficulty hitting desired paces
Cold hands and feet
What are recommended healthy serum ferritin levels?
The World Health Organization (WHO) recommends that healthy individuals maintain serum ferritin levels between 20-150 ng/mL for females and 20-200 ng/mL for males. This large range should be individualized for athletes based on activity level, exposure to high altitudes, and other factors.
Athlete optimal ranges are influenced by gender, age, frequency, duration, and intensity of training. Due to increased demands for iron as an athlete, optimal serum ferritin ranges vary from the general population recommendations.
While optimal levels for all endurance athletes is highly debated, it is thought that a ferritin level of at least 40 ng/mL is the minimum amount required. Male runners and any runners that are exposed to an increased altitude may need a serum ferritin > 50 ng/mL to optimize performance.
It is also important to understand that during times of stress, ferritin levels can be falsely elevated, meaning you may have low ferritin levels without your labs indicating that this is the case. Whether the stress is attributed to hard training sessions, racing season, illness, or general life stress, it’s important to consider the full picture when assessing ferritin.
How often should I check my ferritin levels?
Depending on your history with iron deficiency, sex, training altitude, diet, and training volume, recommendations for blood draw timing vary. It is important to also ask for your iron panel in combination with your ferritin levels to consider both components.
How can I increase my ferritin levels?
Ferritin levels are impacted by a variety of factors. Ask yourself these questions to understand if you are optimizing your ferritin levels!
Are you eating enough to support your energy needs?
Are you eating enough carbohydrates?
Are you eating a variety of foods that help provide different micronutrients?
Are you eating iron-rich foods? (i.e., red meat, poultry, seafood, beans, lentils, dark leafy greens, iron-fortified cereal, etc.)
Are you pairing iron-rich foods with vitamin C to promote absorption?
Do you have any concerns with your gut health? (i.e., bloating, diarrhea, abdominal pain, etc.)
Are you taking an adequate number of rest days to fully recover?
Are you managing stress levels well?
Is it necessary to take an iron supplement?
For many athletes, iron supplementation, in combination with the above considerations, may be necessary to effectively reach ferritin levels > 40 ng/mL.
Timing
Only 10-35% of the iron we consume, whether in food or supplement form, is absorbed by the body. This makes the timing of supplementation an important factor to ensure proper absorption and utilization.
To optimize absorption, take iron by itself, either 1 hour before or 2 hours after a meal. For athletes who run in the morning, take your iron supplement immediately after your run. Wait about 1 hour after your run to eat to reduce nutrient competition for absorption, but also still optimize post-work nutrition.
If your iron supplement doesn’t include a source of vitamin C source, either add a vitamin C supplement when you take your iron, or take your iron supplement with a vitamin C rich food. Some sources of vitamin C include citrus fruits, berries, broccoli, bell peppers, and tomatoes.
Brands
At GracesGrit, we recommend taking Thorne’s Iron Bisglycinate supplement with their Vitamin C supplement to maximize absorption. If you’re looking for a one-stop shop supplement that includes both iron and vitamin C, we recommend trying out Thorne’s Ferrasorb product! Click here to receive 20% off your order at Thorne.
Before taking any supplement, consult your physician or dietitian to see what’s the best fit for you.
The bottom line:
Knowing and understanding your ferritin levels can help you take action to improve your iron stores through lifestyle changes and supplementation. Ferritin levels are highly individualized, therefore regularly monitoring your levels and performance can help you find the optimal level for you! For runners, if your ferritin is < 40 ng/mL, your performance is impacted by the lack of iron. Optimizing your nutrition, recovery, and supplementation protocol will help you boost your ferritin levels and help you get back on track with training!
Have low ferritin and looking for some guidance getting your levels back up? Schedule an intro call today to discuss how nutrition plays a key role in serum ferritin!
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References:
Coates, Alexandra BSc; Mountjoy, Margo MD, PhD,; Burr, Jamie PhD. Incidence of iron deficiency and iron deficient anemia in elite runners and triathletes. Clinical Journal of Sport Medicine 27(5):p 493-498, September 2017. | DOI: 10.1097/JSM.0000000000000390
WHO guideline on use of ferritin concentrations to assess iron status in individuals and populations. World Health Organization. Accessed July 8, 2025. https://www.who.int/publications/i/item/9789240000124.
Solberg A, Reikvam H. Iron status and physical performance in athletes. Life (Basel). 2023;13(10):2007. Published 2023 Oct 2. doi:10.3390/life13102007
Sim M, Garvican-Lewis LA, Cox GR, et al. Iron considerations for the athlete: a narrative review. Eur J Appl Physiol. 2019;119(7):1463-1478. doi:10.1007/s00421-019-04157-y
McCormick R, Moretti D, McKay AKA, et al. The Impact of Morning versus Afternoon Exercise on Iron Absorption in Athletes. Med Sci Sports Exerc. 2019;51(10):2147-2155. doi:10.1249/MSS.0000000000002026
