Klean Iron 27 mg by Klean Athlete

If your Ferritin (your iron storage protein) is low or your CBC and Hemoglobin show iron‑deficiency patterns, an iron supplement makes a real difference. This 27 mg carbonyl iron fits menstruating endurance athletes, vegans and vegetarians, and frequent blood donors, especially if fatigue or poor training recovery tracks with low Ferritin. It’s a maintenance or gentle repletion dose; for established iron‑deficiency anemia, clinicians usually use higher elemental iron and closer lab follow‑up.

Carbonyl iron is pure elemental iron in tiny particles that dissolve in stomach acid before absorption in the small intestine. That slow, acid‑dependent release is why it’s typically gentler on the gut than ferrous sulfate, with less nausea or constipation at comparable elemental doses. Once absorbed, iron builds Hemoglobin (the oxygen carrier in red blood cells) and myoglobin (oxygen storage in muscle), which explains improvements in VO2-limited training and reduced exertional fatigue as stores normalize.

Take one tablet daily on an empty stomach, ideally in the morning or every other morning to align with hepcidin (the hormone that temporarily blocks iron absorption) dynamics. Vitamin C or orange juice can improve absorption. Separate from calcium, magnesium, coffee, tea, and high‑fiber cereals by at least two hours. Recheck Ferritin and Hemoglobin within 4 to 8 weeks; filling iron stores often takes 8 to 12 weeks, and longer if your baseline was very low.

Skip supplemental iron if you have hemochromatosis (a genetic iron‑overload disorder), unexplained high Ferritin, repeated transfusions, or active infection unless your clinician directs otherwise. Space iron by 4+ hours from levothyroxine, fluoroquinolones, tetracyclines, and bisphosphonates, since iron binds these drugs and blocks their effect. If you use acid‑suppressing meds (PPIs), absorption from carbonyl iron can drop; pair with vitamin C and get labs to confirm it’s working.