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Summary
Iron is an essential mineral for oxygen transport and mitochondrial function. In adults with iron deficiency or low ferritin, supplementation can improve fatigue, attention, and exercise tolerance; benefits are minimal in replete individuals and excess iron can be harmful.
Ferrasorb — Thorne
Provides iron, essential B vitamins, and vitamin C for comprehensive nutritional support for anemia. NSF Certified for Sport®.
Mental Clarity, Focus, and Energy
- Cognitive and energy effects: Strongest in iron‑deficient states, with improvements in attention, processing speed, and fatigue after repletion.
- Little to no cognitive benefit is expected if ferritin and hemoglobin are normal.
Brain Health
- Mechanisms: Supports hemoglobin and myoglobin, mitochondrial enzymes, and neurotransmitter synthesis; deficiency impairs oxygen delivery and energy metabolism.
Gut Health
- Tolerability: GI upset, constipation, or nausea are common with certain forms. Taking with food or using gentler forms (e.g., iron bisglycinate) can improve tolerance.
- Absorption: Vitamin C and an empty stomach increase absorption; calcium, coffee/tea, and some grains reduce it.
Brain-Gut Axis
- Restoring iron status can reduce systemic fatigue and stress reactivity, indirectly supporting gut–brain communication. Monitor GI side effects from iron salts.
Evidence Summary
Benefit Area | Evidence Quality | Effect Noted | Notes |
Mental Clarity | Moderate | Improved attention in deficiency | Repletion dependent |
Focus Enhancement | Moderate | Task performance improves with repletion | No benefit when replete |
Energy Support | Strong | Reduced fatigue in deficiency | Hemoglobin/ferritin guided |
Brain Health | Moderate | Neurotransmitter and mitochondrial support | Status dependent |
Gut Health | Limited | GI side effects possible | Formulation matters |
Brain–Gut Optimization | Emerging | Reduced fatigue‑stress signaling | Indirect |
Typical Dosing Instructions
- Standard dose: As directed by clinician; common OTC ranges 18–27 mg elemental iron daily; higher doses short‑term for deficiency
- Timing: Morning or between meals with vitamin C for absorption; take with food if GI upset
- Form: Ferrous bisglycinate or gluconate for gentler tolerance; avoid taking with calcium/coffee/tea
- Notes: Continue several months after normalization to replenish stores, per clinician guidance
Safety Considerations
- General safety: Avoid unnecessary iron if replete; excess iron can be harmful
- Common effects: Constipation, nausea, dark stools
- Contraindications and cautions: Hemochromatosis or iron overload; interactions with thyroid meds, tetracyclines, quinolones—separate by several hours
- Populations: Use under clinician guidance in pregnancy
- Monitoring: Track ferritin, hemoglobin, transferrin saturation; reassess need regularly
References
- Effect of iron supplementation on fatigue in non‑anaemic menstruating women with low ferritin: randomized controlled trial, CMAJ, 2012-07-09
- Iron therapy for unexplained fatigue in non‑anaemic adults: systematic review and meta‑analysis, BMJ, 2003-05-24
- Iron deficiency and cognitive functions, Nutrients, 2020-06-10
- WHO guideline on use of ferritin concentrations to assess iron status, World Health Organization, 2020-11-01
- Iron Fact Sheet for Health Professionals, NIH Office of Dietary Supplements, 2024-06-12
- Iron absorption: inhibitors and enhancers (tea/coffee, calcium, vitamin C), Annals of Nutrition & Metabolism, 2017-03-15
- Oral iron supplementation side effects and tolerability across formulations: systematic review and meta‑analysis, The Lancet Haematology, 2015-10-01