Component

Ferrous sulfate

Inorganic iron(II) sulfate preparation; clinical doses are expressed as elemental iron when specified. Hydration state is not inferred.

6 recorded relationships. Experimental role, claim status and evidence remain attached to each record.

Read recorded mechanisms Open recursive mind map

How nutrients influence it

Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.

How nutrients reach it in more than one step

Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.

Tracing routes…

What it does

Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.

Recorded relationships

What it acts on

  1. Fractional iron absorption on the initial and alternate-day doses was 40–50% higher than on the consecutive-day dose.

    Ferrous sulfate → Nonheme iron absorption source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/iron-research/31413088.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8b12cbd03fa44886ae6bf6bd4d58db7bbbf21dad0461eef9b63d3c7da25c542c", "start_char": 0, "end_char": 2483, "text_sha256": "8b12cbd03fa44886ae6bf6bd4d58db7bbbf21dad0461eef9b63d3c7da25c542c"}
    experimental_model
    Stable-isotope crossover absorption study
    exposure
    100 or 200 mg ferrous sulfate on consecutive and alternate days
    limitations
    Absorption trial, not a universal dosing directive; the indexed abstract contains implausible units for baseline hemoglobin/ferritin, which are not reproduced as clinical thresholds.
    nutrient_topic
    Iron research collection; topical membership is not evidence of a direct dietary effect. · Iron
    organism
    19 women with iron-deficiency anemia
    plain_language
    Spacing changed absorption in this trial, but the study alone does not decide every patient’s regimen.
    primary_references
    [iron-p31413088] Iron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient anemic women. (2020). https://pubmed.ncbi.nlm.nih.gov/31413088/ DOI: 10.3324/haematol.2019.220830
    tissue_or_cell_type
    Oral absorption and hepcidin

    Iron: absorption, trafficking, iron-dependent enzymes and nutrient interactions (2026-09-17) · lines 1304–1315

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Stable-isotope crossover absorption study · source_derived_draft · unverified_draft

    ### iron-alternate-absorption Fractional iron absorption on the initial and alternate-day doses was 40–50% higher than on the consecutive-day dose. Condition category: normal nutrient_topic: Iron research collection; topical membership is not evidence of a direct dietary effect. plain_language: Spacing changed absorption in this trial, but the study alone does not decide every patient’s regimen. organism: 19 women with iron-deficiency anemia tissue_or_cell_type: Oral absorption and hepcidin experimental_model: Stable-isotope crossover absorption study limitations: Absorption trial, not a universal dosing directive; the indexed abstract contains implausible units for baseline hemoglobin/ferritin, which are not reproduced as clinical thresholds. exposure: 100 or 200 mg ferrous sulfate on consecutive and alternate days evidence_span: {"source_cache": "artifacts/iron-research/31413088.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8b12cbd03fa44886ae6bf6bd4d58db7bbbf21dad0461eef9b63d3c7da25c542c", "start_char": 0, "end_char": 2483, "text_sha256": "8b12cbd03fa44886ae6bf6bd4d58db7bbbf21dad0461eef9b63d3c7da25c542c"} [iron-p31413088] Iron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient anemic women. (2020). https://pubmed.ncbi.nlm.nih.gov/31413088/ DOI: 10.3324/haematol.2019.220830
    Complete structured claim and evidence

  2. Increasing the dose from 40 to 240 mg reduced fractional absorption but increased the absolute amount absorbed from 6.7 to 18.1 mg.

    Ferrous sulfate → Nonheme iron absorption source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/iron-research/26289639.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "67eb8d47c0df5398c03a2a73fdd7698efc0467e85db72cfdcc829fab72b90096", "start_char": 0, "end_char": 1708, "text_sha256": "67eb8d47c0df5398c03a2a73fdd7698efc0467e85db72cfdcc829fab72b90096"}
    experimental_model
    Stable-isotope dose studies
    exposure
    40–240 mg oral labeled ferrous sulfate; successive or twice-daily doses
    limitations
    Short-term fractional absorption is not equivalent to long-term hemoglobin recovery; dose values describe the experiment.
    nutrient_topic
    Iron research collection; topical membership is not evidence of a direct dietary effect. · Iron
    organism
    54 nonanemic iron-depleted young women
    plain_language
    A smaller absorbed percentage can still represent more milligrams; the two measurements should not be confused.
    primary_references
    [iron-p26289639] Oral iron supplements increase hepcidin and decrease iron absorption from daily or twice-daily doses in iron-depleted young women. (2015). https://pubmed.ncbi.nlm.nih.gov/26289639/ DOI: 10.1182/blood-2015-05-642223
    tissue_or_cell_type
    Iron absorption and circulating hepcidin

    Iron: absorption, trafficking, iron-dependent enzymes and nutrient interactions (2026-09-17) · lines 1291–1302

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Stable-isotope dose studies · source_derived_draft · unverified_draft

    ### iron-fraction-versus-amount Increasing the dose from 40 to 240 mg reduced fractional absorption but increased the absolute amount absorbed from 6.7 to 18.1 mg. Condition category: normal nutrient_topic: Iron research collection; topical membership is not evidence of a direct dietary effect. plain_language: A smaller absorbed percentage can still represent more milligrams; the two measurements should not be confused. organism: 54 nonanemic iron-depleted young women tissue_or_cell_type: Iron absorption and circulating hepcidin experimental_model: Stable-isotope dose studies limitations: Short-term fractional absorption is not equivalent to long-term hemoglobin recovery; dose values describe the experiment. exposure: 40–240 mg oral labeled ferrous sulfate; successive or twice-daily doses evidence_span: {"source_cache": "artifacts/iron-research/26289639.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "67eb8d47c0df5398c03a2a73fdd7698efc0467e85db72cfdcc829fab72b90096", "start_char": 0, "end_char": 1708, "text_sha256": "67eb8d47c0df5398c03a2a73fdd7698efc0467e85db72cfdcc829fab72b90096"} [iron-p26289639] Oral iron supplements increase hepcidin and decrease iron absorption from daily or twice-daily doses in iron-depleted young women. (2015). https://pubmed.ncbi.nlm.nih.gov/26289639/ DOI: 10.1182/blood-2015-05-642223
    Complete structured claim and evidence

  3. Fatigue scores decreased 47.7% with iron versus 28.8% with placebo; the between-group difference was significant (P=0.02).

    Ferrous sulfate → Self-reported fatigue severity source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    biomarker_context Imported condition classification; unverified.
    evidence_span
    {"source_cache": "artifacts/iron-research/22777991.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7d8d360cee2d71d5cf1d7b19bbd5c740164d24c16daf98fe4519551573f8fb75", "start_char": 0, "end_char": 1708, "text_sha256": "7d8d360cee2d71d5cf1d7b19bbd5c740164d24c16daf98fe4519551573f8fb75"}
    experimental_model
    Randomized placebo-controlled 12-week trial
    exposure
    Ferritin below 50 micrograms/L, hemoglobin above 12 g/dL; 80 mg elemental iron/day versus placebo
    limitations
    Trial inclusion criteria are not a universal deficiency threshold. No significant improvement in depression, anxiety or overall quality of life.
    nutrient_topic
    Iron research collection; topical membership is not evidence of a direct dietary effect. · Iron
    organism
    198 nonanemic menstruating women with fatigue
    plain_language
    Normal-range hemoglobin did not exclude an iron-responsive fatigue outcome in this selected group.
    primary_references
    [iron-p22777991] Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial. (2012). https://pubmed.ncbi.nlm.nih.gov/22777991/ DOI: 10.1503/cmaj.110950
    tissue_or_cell_type
    Reported symptoms and blood markers
    trigger_kind
    biomarker_context Imported condition classification; unverified.

    Iron: absorption, trafficking, iron-dependent enzymes and nutrient interactions (2026-09-17) · lines 1317–1328

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Randomized placebo-controlled 12-week trial · source_derived_draft · unverified_draft

    ### iron-nonanemic-fatigue Fatigue scores decreased 47.7% with iron versus 28.8% with placebo; the between-group difference was significant (P=0.02). Condition category: biomarker_context nutrient_topic: Iron research collection; topical membership is not evidence of a direct dietary effect. plain_language: Normal-range hemoglobin did not exclude an iron-responsive fatigue outcome in this selected group. organism: 198 nonanemic menstruating women with fatigue tissue_or_cell_type: Reported symptoms and blood markers experimental_model: Randomized placebo-controlled 12-week trial limitations: Trial inclusion criteria are not a universal deficiency threshold. No significant improvement in depression, anxiety or overall quality of life. exposure: Ferritin below 50 micrograms/L, hemoglobin above 12 g/dL; 80 mg elemental iron/day versus placebo evidence_span: {"source_cache": "artifacts/iron-research/22777991.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7d8d360cee2d71d5cf1d7b19bbd5c740164d24c16daf98fe4519551573f8fb75", "start_char": 0, "end_char": 1708, "text_sha256": "7d8d360cee2d71d5cf1d7b19bbd5c740164d24c16daf98fe4519551573f8fb75"} [iron-p22777991] Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial. (2012). https://pubmed.ncbi.nlm.nih.gov/22777991/ DOI: 10.1503/cmaj.110950
    Complete structured claim and evidence

  4. Doses of at least 60 mg raised hepcidin at 24 hours and reduced fractional absorption of subsequent iron by 35–45%.

    Ferrous sulfate → Circulating hepcidin concentration source_derived_draftungraded
    Experimental context and source evidence
    evidence_span
    {"source_cache": "artifacts/iron-research/26289639.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "67eb8d47c0df5398c03a2a73fdd7698efc0467e85db72cfdcc829fab72b90096", "start_char": 0, "end_char": 1708, "text_sha256": "67eb8d47c0df5398c03a2a73fdd7698efc0467e85db72cfdcc829fab72b90096"}
    experimental_model
    Stable-isotope dose studies
    exposure
    40–240 mg oral labeled ferrous sulfate; successive or twice-daily doses
    limitations
    Short-term fractional absorption is not equivalent to long-term hemoglobin recovery; dose values describe the experiment.
    nutrient_topic
    Iron research collection; topical membership is not evidence of a direct dietary effect. · Iron
    organism
    54 nonanemic iron-depleted young women
    plain_language
    An iron dose can temporarily make the next dose harder to absorb.
    primary_references
    [iron-p26289639] Oral iron supplements increase hepcidin and decrease iron absorption from daily or twice-daily doses in iron-depleted young women. (2015). https://pubmed.ncbi.nlm.nih.gov/26289639/ DOI: 10.1182/blood-2015-05-642223
    tissue_or_cell_type
    Iron absorption and circulating hepcidin

    Iron: absorption, trafficking, iron-dependent enzymes and nutrient interactions (2026-09-17) · lines 1278–1289

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Stable-isotope dose studies · source_derived_draft · unverified_draft

    ### iron-oral-iron-hepcidin Doses of at least 60 mg raised hepcidin at 24 hours and reduced fractional absorption of subsequent iron by 35–45%. Condition category: normal nutrient_topic: Iron research collection; topical membership is not evidence of a direct dietary effect. plain_language: An iron dose can temporarily make the next dose harder to absorb. organism: 54 nonanemic iron-depleted young women tissue_or_cell_type: Iron absorption and circulating hepcidin experimental_model: Stable-isotope dose studies limitations: Short-term fractional absorption is not equivalent to long-term hemoglobin recovery; dose values describe the experiment. exposure: 40–240 mg oral labeled ferrous sulfate; successive or twice-daily doses evidence_span: {"source_cache": "artifacts/iron-research/26289639.abstract.txt", "locator": "Exact primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "67eb8d47c0df5398c03a2a73fdd7698efc0467e85db72cfdcc829fab72b90096", "start_char": 0, "end_char": 1708, "text_sha256": "67eb8d47c0df5398c03a2a73fdd7698efc0467e85db72cfdcc829fab72b90096"} [iron-p26289639] Oral iron supplements increase hepcidin and decrease iron absorption from daily or twice-daily doses in iron-depleted young women. (2015). https://pubmed.ncbi.nlm.nih.gov/26289639/ DOI: 10.1182/blood-2015-05-642223
    Complete structured claim and evidence

Where it participates (unsigned role)

  1. Serum thyroxine was higher with dual-fortified salt than with iodized salt alone (P<0.05), with lower reported hypothyroidism and goiter prevalence (P<0.01).

    Iron → Serum total thyroxine concentration source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    true
    evidence_location
    Primary indexed abstract.
    experimental_model
    Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence
    exposure
    Iodized salt 25 micrograms iodine/g versus dual-fortified salt with the same iodine plus 1 mg iron/g as microencapsulated ferrous sulfate; 40-week measurements.
    limitations
    Clinical intervention and thyroid endpoints do not identify the exact iron-dependent step. Iodized-salt-only participants also improved. Related publications from this cohort are not independent trials. The abstract does not provide the exact between-group thyroxine effect size. The two iron trials have distinct populations and endpoints; their hormone results are not declared a contradiction.
    nutrient_topic
    Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine
    organism
    Homo sapiens
    plain_language
    This iron–iodine trial also found a hormone response.
    primary_references
    [iod-clin-zimmer2002] Addition of microencapsulated iron to iodized salt improves the efficacy of iodine in goitrous, iron-deficient children: a randomized, double-blind, controlled trial. (2002). https://pubmed.ncbi.nlm.nih.gov/12457449/ DOI: 10.1530/eje.0.1470747
    tissue_or_cell_type
    Thyroid volume, circulating thyroxine and iron indices
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1244–1256

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence · source_derived_draft · unverified_draft

    ### iod-clin-dual-salt-thyroxine Serum thyroxine was higher with dual-fortified salt than with iodized salt alone (P<0.05), with lower reported hypothyroidism and goiter prevalence (P<0.01). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: This iron–iodine trial also found a hormone response. organism: Homo sapiens tissue_or_cell_type: Thyroid volume, circulating thyroxine and iron indices experimental_model: Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence limitations: Clinical intervention and thyroid endpoints do not identify the exact iron-dependent step. Iodized-salt-only participants also improved. Related publications from this cohort are not independent trials. The abstract does not provide the exact between-group thyroxine effect size. The two iron trials have distinct populations and endpoints; their hormone results are not declared a contradiction. exposure: Iodized salt 25 micrograms iodine/g versus dual-fortified salt with the same iodine plus 1 mg iron/g as microencapsulated ferrous sulfate; 40-week measurements. cross_nutrient: true evidence_location: Primary indexed abstract. [iod-clin-zimmer2002] Addition of microencapsulated iron to iodized salt improves the efficacy of iodine in goitrous, iron-deficient children: a randomized, double-blind, controlled trial. (2002). https://pubmed.ncbi.nlm.nih.gov/12457449/ DOI: 10.1530/eje.0.1470747
    Complete structured claim and evidence

  2. Mean thyroid-volume reduction at 40 weeks was 38% with dual iron–iodine salt versus 18% with iodine-only salt (P<0.01).

    Iron → Thyroid volume source_derived_draftungraded
    Experimental context and source evidence
    availability_state
    nutrient_deficiency Imported condition classification; unverified.
    cross_nutrient
    true
    evidence_location
    Primary indexed abstract.
    experimental_model
    Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence
    exposure
    Iodized salt 25 micrograms iodine/g versus dual-fortified salt with the same iodine plus 1 mg iron/g as microencapsulated ferrous sulfate; 40-week measurements.
    limitations
    Clinical intervention and thyroid endpoints do not identify the exact iron-dependent step. Iodized-salt-only participants also improved. Related publications from this cohort are not independent trials.
    nutrient_topic
    Iodine research collection; topical membership is not evidence of a direct dietary effect. · Iodine
    organism
    Homo sapiens
    plain_language
    Adding iron improved the response to the same amount of iodine in this trial.
    primary_references
    [iod-clin-zimmer2002] Addition of microencapsulated iron to iodized salt improves the efficacy of iodine in goitrous, iron-deficient children: a randomized, double-blind, controlled trial. (2002). https://pubmed.ncbi.nlm.nih.gov/12457449/ DOI: 10.1530/eje.0.1470747
    tissue_or_cell_type
    Thyroid volume, circulating thyroxine and iron indices
    trigger_kind
    nutrient_deficiency Imported condition classification; unverified.

    Iodine: thyroid hormone production, deficiency, excess and nutrient interactions (2026-09-17) · lines 1230–1242

    AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence · source_derived_draft · unverified_draft

    ### iod-clin-dual-salt-volume Mean thyroid-volume reduction at 40 weeks was 38% with dual iron–iodine salt versus 18% with iodine-only salt (P<0.01). Condition category: nutrient_deficiency nutrient_topic: Iodine research collection; topical membership is not evidence of a direct dietary effect. plain_language: Adding iron improved the response to the same amount of iodine in this trial. organism: Homo sapiens tissue_or_cell_type: Thyroid volume, circulating thyroxine and iron indices experimental_model: Nine-month randomized double-blind controlled trial in 377 goitrous children aged 6–15 with high anemia prevalence limitations: Clinical intervention and thyroid endpoints do not identify the exact iron-dependent step. Iodized-salt-only participants also improved. Related publications from this cohort are not independent trials. exposure: Iodized salt 25 micrograms iodine/g versus dual-fortified salt with the same iodine plus 1 mg iron/g as microencapsulated ferrous sulfate; 40-week measurements. cross_nutrient: true evidence_location: Primary indexed abstract. [iod-clin-zimmer2002] Addition of microencapsulated iron to iodized salt improves the efficacy of iodine in goitrous, iron-deficient children: a randomized, double-blind, controlled trial. (2002). https://pubmed.ncbi.nlm.nih.gov/12457449/ DOI: 10.1530/eje.0.1470747
    Complete structured claim and evidence

In the sources

Preserved passages that mention this component, quoted exactly. Open one to read it in context.

    This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.

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