Iron is not a longevity supplement. The body can take it in and can barely eliminate it. When stores are empty, bringing levels back restores blood oxygen-carrying protein, eases fatigue, and can quiet restless legs; intravenous iron in iron-deficient heart failure is tied to fewer hospitalizations. Extra iron with already-full stores has not shown a longevity gain. (Full Review)

Protocol

Standard repletion (hematology/primary care)

40–100 mg elemental iron

Single daily or alternate-day dose for 8–12 weeks, then until ferritin recovers

Time of day

Morning

Away from coffee, tea, calcium, and high-phytate meals; vitamin C–containing food can sit with the dose

Baseline biomarkers

Ferritin, TSAT, hemoglobin, CRP

These markers decide whether to treat, the route, and when to stop

Time to effect

Hemoglobin

Moves by 2 weeks

Normalizes over 4–8 weeks if losses are controlled

Restless legs

2–12 weeks

Can shift with repletion when iron is low

Fatigue

2–12 weeks

Unexplained fatigue when ferritin is low but hemoglobin is normal

Benefits

High: Restoration of hemoglobin in iron-deficiency anemia; Relief of restless-legs symptoms when iron is low; Better exercise performance in iron-deficient women without anemia; Fewer heart-failure events with intravenous iron; Fewer low-birth-weight infants with pregnancy supplementation

Medium: Less unexplained fatigue when ferritin is low but hemoglobin is normal

Low: Cognitive performance in iron-deficient adults

Speculative: Healthspan extension from supplementing already-replete adults

Contraindications

Confirmed hereditary hemochromatosis or other primary iron-overload disease (HFE C282Y homozygosity with TSAT ≥45% and ferritin above sex-specific thresholds)

Secondary iron overload (repeated transfusions, thalassemia with high ferritin, sideroblastic anemia)

Unexplained TSAT ≥45% with elevated ferritin pending cause-finding

Iron-replete men and postmenopausal women without a documented deficiency or a disease-specific intravenous-iron indication

Active serious infection until the infection is controlled (especially for intravenous iron)

Known serious hypersensitivity to a given intravenous iron product (that product only)

Key Interactions

Levothyroxine (separate by at least 4 hours)

Tetracycline and fluoroquinolone antibiotics (ciprofloxacin, doxycycline; iron 2 hours before or 3 hours after)

Acid reducers (omeprazole, pantoprazole, famotidine)

Calcium, zinc, magnesium, and antacids (separate by ≥2 hours)

Vitamin C (potentiating)

Other iron products and iron-fortified medical foods (past 45 mg/day adult upper intake level)

ACE inhibitors (lisinopril, enalapril) (monitor)

Risk & Side Effects

High: Gastrointestinal intolerance of oral iron; Hypophosphatemia after ferric carboxymaltose; Infection after intravenous iron; Infusion reactions and rare anaphylaxis with intravenous iron

Medium: Iron overload and organ injury when regulation fails or intake is unsupervised; Acute iron poisoning, especially in children; Higher death rates with supplemental iron in older women; Cardiometabolic associations of high heme-iron intake

Speculative: Faster cellular aging from catalytic iron in already-replete users; Shift in gut microbial balance

Monitoring

Marker	Target	Why
Ferritin	50–150 ng/mL (restless legs often ≥75–100)	Stored iron
TSAT	20–45%	Iron immediately available to tissues
Hemoglobin	Men ~13.5–15.5 g/dL; women ~12.5–14.5 g/dL	Oxygen-carrying capacity
Serum iron + TIBC	No established functional target	Separates deficiency from inflammation
CRP	<1.0 mg/L	Confounds ferritin
Phosphate (after FCM)	2.5–4.5 mg/dL	Detects FCM phosphate wasting

Cadence: Baseline before treatment-dose iron; 6–8 weeks after oral repletion starts; 3–6 months after stores refill; every 6–12 months if bleeding, endurance training, gut disease, or prior overload remains. Delayed ferritin after intravenous iron; phosphate 2–6 weeks after ferric carboxymaltose

Qualitative Assessment

Daytime energy and exercise tolerance
Restless-legs urge and sleep continuity
Gut comfort, stool color, and nausea after doses
Cognitive clarity and cold intolerance
In overload phenotypes: joint pain, bronze skin, new diabetes, unexplained liver-enzyme rise

Iron for Health & Longevity

Protocol

Benefits

Risk & Side Effects

Monitoring

Qualitative Assessment