Mechanism of Action
Iron operates at multiple levels of cellular metabolism. Within mitochondria (the cell's energy powerhouses), it forms the catalytic core of electron transport chain complexes. Without iron, ATP production (the universal energy molecule) collapses.
Iron is also the central component of haemoglobin, the red blood cell protein that captures oxygen in the lungs and delivers it to tissues. Myoglobin, its muscular counterpart, serves a comparable role as an oxygen reserve within muscle fibres.
Beyond oxygen transport, iron participates in DNA synthesis and cell division. It also contributes to the production of neurotransmitters such as dopamine and serotonin, as well as to the normal function of the immune system.
The downside of this reactivity: free iron (not bound to a transport protein) can react with hydrogen peroxide to generate hydroxyl radicals. These reactive species damage DNA, membrane lipids, and proteins. The body sequesters iron in ferritin and transferrin to contain this threat. This control weakens when stores exceed storage capacity.
Key Benefits
- Strong
Iron contributes to the normal formation of red blood cells and haemoglobin, as well as to normal oxygen transport in the body. A Cochrane meta-analysis of 67 trials confirms that iron supplementation significantly increases haemoglobin concentrations in menstruating women with low stores.
- Strong
Iron contributes to the reduction of tiredness and fatigue. Several randomised controlled trials show that supplementation improves fatigue scores in women with low ferritin but normal haemoglobin, with significant results from 12 weeks onward.
- Strong
Iron contributes to normal energy-yielding metabolism. Its role in the mitochondrial electron transport chain is documented by decades of biochemical research and confirmed by clinical studies measuring improved aerobic capacity after correcting low stores.
- Strong
Iron has a role in the process of cell division, a fundamental mechanism for tissue renewal and the maintenance of biological integrity over time.
- Moderate
Iron contributes to normal cognitive function. A controlled trial in young women shows that supplementation improves cognitive processing speed and working memory, an effect particularly pronounced in those with low baseline stores.
- Moderate
Iron contributes to the normal function of the immune system. Adequate iron status supports lymphocyte proliferation and immune response, an effect supported by clinical data in adults.
- Moderate
Iron supplementation improves physical capacity and endurance in individuals with low stores. A systematic review of controlled trials in female athletes confirms significant gains in aerobic performance.
Dosage & Forms
Iron forms available for supplementation fall into three categories. Inorganic salts (sulphate, fumarate, gluconate) offer a high cost-effectiveness ratio but frequently cause digestive discomfort. Encapsulated forms (liposomal ferric pyrophosphate) improve tolerance at a higher technological cost. Amino acid chelates, including the ferrous bisglycinate selected by Singular, combine high bioavailability with digestive tolerance.
Recommended nutritional intakes vary by profile: 8 mg per day for adult men, 18 mg for women of reproductive age, 27 mg during pregnancy. A randomised trial published in The Lancet Haematology showed that iron absorption is optimal with single morning doses on alternate days. Iron supplementation in the Singular formula is conditional and individualized. The dose is calibrated to each member's biological profile.
In the Singular Formula
Inclusion rationale
Iron contributes to the normal formation of red blood cells and hemoglobin, to normal oxygen transport in the body and to the reduction of tiredness and fatigue. Included only according to your profile. Iron is a double-edged element: indispensable for oxygen transport and cellular respiration, but potentially pro-oxidant in excess via the Fenton reaction. This is why its supplementation is personalized and not systematic in the formula. Vitamin C (present in the formula) increases non-heme iron absorption by keeping it in reduced form (Fe2+) in the intestinal tract. The balance with zinc and copper (also present in the formula in bisglycinate form) is carefully calibrated to avoid mineral absorption competition. The bisglycinate form (iron chelated to two glycine molecules) is absorbed via amino acid transporters in the intestine, bypassing the DMT1 transporter for ionic iron. This distinct absorption mechanism significantly reduces classic digestive side effects (nausea, constipation, dark stools) and provides a bioavailability 3 to 4 times greater than ferrous sulfate, allowing lower effective doses that are better tolerated.
Selected form
Ferrous bisglycinate: each iron atom (Fe2+) is chelated to two glycine molecules, the smallest natural amino acid. Chelation means iron is stably bonded to an amino acid, allowing it to cross the intestinal wall via amino acid transporters rather than conventional iron pathways. Result: significantly superior absorption compared to classic ferrous salts (sulphate, fumarate, gluconate) and optimal digestive tolerance. Iron contributes to the reduction of tiredness and to normal oxygen transport in the body. Quality: vegan, non-GMO, no excipient, Halal and Kosher certified.
Formula dosage
0 to 21 mg.
Synergies in the formula
Safety & Precautions
Ferrous bisglycinate is well tolerated at standard supplementation doses. The chelated form generates significantly fewer digestive discomforts than classic ferrous salts.
Iron supplementation is not recommended without prior assessment of iron status. Excess iron accumulates in organs and promotes oxidative stress through free radical generation. Individuals with haemochromatosis (a genetic condition causing excessive iron absorption) should not supplement without specialist supervision.
Iron absorption is reduced by calcium, tea, coffee, and phytates (found in whole grains and legumes). Vitamin C, conversely, enhances its absorption. A two-hour interval between iron intake and calcium or zinc is recommended to limit absorption competition.
Pregnant or breastfeeding women, as well as individuals taking medication, are advised to consult a healthcare professional before any iron supplementation.
Scientific Studies
| Authors | Year | Type | Journal | |
|---|---|---|---|---|
| Low MS et al. | 2016 | Meta-analysis | Cochrane Database of Systematic Reviews | View on PubMed |
Daily iron supplementation for improving anaemia, iron status and health in menstruating women Cochrane systematic review of 67 trials confirming that daily iron supplementation increases haemoglobin and ferritin in menstruating women, with significant fatigue reduction. | ||||
| Tolkien Z et al. | 2015 | Meta-analysis | PLoS One | View on PubMed |
Ferrous sulfate supplementation causes significant gastrointestinal side-effects in adults: a systematic review and meta-analysis Meta-analysis of 43 trials demonstrating that ferrous sulphate causes significant gastrointestinal effects compared to placebo, supporting the choice of better-tolerated forms such as bisglycinate. | ||||
| Pasricha SR et al. | 2021 | Systematic Review | The Lancet | View on PubMed |
Iron deficiency Comprehensive Lancet review covering iron physiology, functional consequences of low stores, and evidence-based supplementation strategies. | ||||
| Vaucher P et al. | 2012 | Randomised Controlled Trial | CMAJ | View on PubMed |
Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial Randomised controlled trial showing that 80 mg daily iron significantly reduces fatigue in women with low ferritin but normal haemoglobin after 12 weeks. | ||||
| Stoffel NU et al. | 2017 | Randomised Controlled Trial | The Lancet Haematology | View on PubMed |
Iron absorption from oral iron supplements given on consecutive versus alternate days and as single morning doses versus twice-daily split dosing in iron-depleted women: two open-label, randomised controlled trials Randomised trial showing that fractional iron absorption is higher with single morning doses on alternate days, redefining dosage strategies. | ||||
| Murray-Kolb LE, Beard JL | 2007 | Randomised Controlled Trial | The American Journal of Clinical Nutrition | View on PubMed |
Iron treatment normalizes cognitive functioning in young women Controlled trial demonstrating that iron supplementation improves cognitive processing speed and working memory in young women with low stores. | ||||