Labs and guidelines differ on the low cutoff: some flag under 30 ng/mL, and recent clinical guidance uses 45. Endurance-heavy training, blood donation, and low dietary iron all drive it down. Ferritin also rises with inflammation, so it is read next to hs-CRP. High ferritin is a physician question and so is any decision to supplement iron, which should never be done blind. Executive Health Edge draws ferritin, iron, and transferrin at month 0, 6, and 12 and coaches the dietary and training inputs; anything that warrants a medical decision goes to the program physician.
What the numbers are
Ferritin is the protein that stores iron; it is the best single measure of how much iron you have in reserve. Serum iron is what is circulating right now, and transferrin is the carrier. Executive Health Edge draws all three, alongside B12 and folate, at month 0, 6, and 12.
Labs and guidelines differ: some flag under 30 ng/mL, and recent clinical guidance uses 45. Your physician decides what any value means for you.
Why it is the fatigue marker most physicals skip
Iron deficiency gets treated as a women’s problem, so a standard men’s physical often does not draw ferritin at all. Meanwhile a man who runs or rows a lot, gives blood twice a year, or eats mostly chicken and plants can quietly run his stores down. Low iron stores are common in men who train hard and are rarely checked. When they progress to anemia, endurance suffers: a heart rate that runs high for the pace, Zone 2 sessions that feel like threshold, and VO2 progress that stalls. He blames his age. The panel tells him which side of that line he is on.
Why it is read next to hs-CRP
Ferritin rises with inflammation, so a “normal” ferritin in a man with elevated hs-CRP can be hiding depleted stores, and a high ferritin can be inflammation rather than iron. The program reads the two together and never reads ferritin alone.
What moves it
- Dietary iron. Red meat, shellfish, and other heme sources within the protein target. Heme iron absorbs far better than plant iron.
- Timing. Coffee and tea with an iron-rich meal cut absorption. Move them.
- Endurance volume. Heavy running and rowing volume drives losses. It is a programming variable.
- Blood donation. Common in this demographic and often forgotten at the draw.
- Blood loss. Anything else is a physician question.
What never happens blind
Iron supplementation. Excess iron is harmful and easy to accumulate. Iron goes on the short supplement list only when the panel and the program physician say so, at a dose the physician sets.
What the research says
- Cutoffs have moved up. Current clinical guidance treats ferritin under 45 ng/mL as diagnostic of iron deficiency when there is no inflammation, and under 100 ng/mL when inflammation is present, which is why ferritin is read next to hs-CRP (Latimer et al., American Family Physician, 2025).
- Coffee and tea at the meal cut iron absorption. A cup of coffee with a hamburger meal cut iron absorption by 39% and tea by 64%; coffee an hour before the meal had no effect, while coffee an hour after still reduced it (Morck et al., American Journal of Clinical Nutrition, 1983).
- Hard training costs iron. Exercise loses iron through red cell breakdown, urine, sweat, and the gut, and raises hepcidin, a hormone that limits iron absorption (Peeling et al., European Journal of Applied Physiology, 2008).
What goes to the physician
Any value the lab flags, high ferritin without inflammation, any low ferritin, and any supplement decision route to the program physician in writing.
This page is coaching information, not medical advice. Questions about medication, hormones, or peptides go to the program physician.