Iron

Tier-BPublic-ready6/30/2026

Blood-Level or Deficiency Marker is closer to a research marker, so it should be read separately from a directly felt benefit.

The 58.7 score includes research signals from patient or disease contexts. General supplement evidence is not repeated enough, so the B tier remains conservative.

Representative tier calculated from paper evidence that passed the collection audit.

Papers analyzed

Caution signal

Low

Context-specific research signal

58.7

Blood-Level or Deficiency MarkerBlood pressure and vascular health markersMenstrual and women's health

Main benefit evidence

The representative ingredient tier is calculated from these target-level evidence groups.

Nutrient status and deficiency

5 studiesTier-B

Blood-Level or Deficiency Marker

Fairly consistent positive signal in studiesResearch marker focusPatient-group study

This is based on lab markers such as blood levels, deficiency correction, or absorption. Read it separately from directly felt outcomes.

Evidence score

56.7

Study context

Patient-group study

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Blood pressure and vascular health

1 studiesTier-C

Blood pressure and vascular health markers

Some positive signal observedResearch marker focusPatient-group study

This card is closer to a measured biomarker or lab outcome than a directly felt user benefit. These findings come from a defined study population, so everyday effects may differ.

Evidence score

44.0

Study context

Patient-group study

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Women's health

1 studiesTier-C

Menstrual and women's health

Some positive signal observedFelt benefit focusPatient-group study

Potential benefit studied in Women's health. These findings come from a defined study population, so everyday effects may differ.

Evidence score

42.1

Study context

Patient-group study

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Immune and respiratory health

1 studiesTier-C

Immune and respiratory support

Some positive signal observedFelt benefit focusPatient-group study

Potential benefit studied in Immune and respiratory health. These findings come from a defined study population, so everyday effects may differ.

Evidence score

42.1

Study context

Patient-group study

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Glucose and metabolic health

1 studiesTier-C

Glucose and metabolic health markers

Some positive signal observedResearch marker focusPatient-group study

This card is closer to a measured biomarker or lab outcome than a directly felt user benefit. These findings come from a defined study population, so everyday effects may differ.

Evidence score

41.4

Study context

Patient-group study

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Blood lipids

1 studiesTier-C

Cholesterol and triglycerides

Some positive signal observedFelt benefit focusPatient-group study

Potential benefit studied in Blood lipids. These findings come from a defined study population, so everyday effects may differ.

Evidence score

41.4

Study context

Patient-group study

This score reflects the strength of this benefit group. The ingredient tier also considers paper count, repetition, population, and study context.

Recent research

Updated This Month10 new papers

Observed range in repeated studies

This range includes studies in specific patient groups. It is not a general dose or recommendation.

Lower observed study value

mg/day

5 independent studies

Higher observed study value

300

mg/day

Only ranges repeated in human, oral, single-ingredient studies are shown.

Not personal dosing instructions, recommendations, or safety limits.

Side effects and combination findings in studies

Findings from studies of this ingredient alone are separated from findings involving another supplement or medication.

Caution index

1.3

Caution band: Low

Caution signals

Side effects + combos + curated rules

Key precautions

No curated contraindication rule is available yet, but literature caution signals are shown below.

These are signals reported in studies. They do not predict what will happen to an individual.

Findings to review with care

Side effects reported for the ingredient alone are separated from findings involving another supplement or medication.

Side effects reported when this ingredient was used alone

Symptoms or adverse events reported in studies of this ingredient without another active ingredient.

Thyrotropin (TSH) and Free thyroxine (FT4) levels1 papers

Iron deficiency in pregnant women is linked to increased serum TSH and decreased FT4 levels, indicating adverse effects on thyroid function.Human studies · Meta-analysis

Side effects1 papers

Women receiving intermittent iron supplements were less likely to experience adverse side effects compared to those receiving daily supplements, though side effects were still more common than in the control group.Human studies · Systematic review

Nausea1 papers

Daily oral iron supplementation significantly increased odds of nausea (adjusted OR 3.56, p<0.001) compared to intermittent supplementation in pregnant women.Human studies · Meta-analysis

Diarrhea1 papers

Daily oral iron supplementation significantly increased odds of diarrhea (adjusted OR 5.40, p=0.002) compared to intermittent supplementation in pregnant women.Human studies · Meta-analysis

Constipation1 papers

Daily oral iron supplementation significantly increased odds of constipation (adjusted OR 1.95, p=0.006) compared to intermittent supplementation in pregnant women.Human studies · Meta-analysis

Birth and infant adverse health outcomes1 papers

Emerging evidence suggests a U-shaped risk curve where high iron status in iron-replete pregnant women and infants is associated with adverse outcomes including growth issues, preterm birth, and gestational diabetes.Human studies · Systematic review

Incidence of diarrhea1 papers

Both SQ-LNS products increased the incidence and longitudinal prevalence of diarrhea, vomiting, and rash/sores.Human studies · Randomized controlled trial

Evidence summaries

Paper IDs and full lists are private. Only study types and summaries are shown.

Key Evidence #1

Public scholarly dataCitation signal: 426

observational

The results do not support use of oral iron supplementation in patients with HFrEF and iron deficiency, and high-dose oral iron did not improve exercise capacity over 16 weeks.

Key Evidence #2

Public scholarly dataCitation signal: 346

observational

Deferiprone therapy was well tolerated and was associated with a reduced dentate and caudate nucleus iron content compared to placebo, which supports more extensive clinical trials into the potential benefits of iron chelation in PD.

Key Evidence #3

Public scholarly dataCitation signal: 251

observational

Prophylactic antenatal oral iron supplements when given intermittently were not effective in preventing iron deficiency anaemia in pregnancy.

3 more summariesLimited representative sample by study type.

Public scholarly dataCitation signal: 167

observational

It is demonstrated that intake of both HI and NHI, as well as adequate dietary energy, are associated with normal iron status levels in young women, and that restrained eaters may be at greater risk of low iron status.

Public scholarly dataCitation signal: 165

observational

Among blood donors with normal hemoglobin levels, low-dose iron supplementation, compared with no supplementation, reduced time to 80% recovery of the postdonation decrease in hemoglobin concentration in donors with low ferritin (≤26 ng/mL) or higher ferritin

Public scholarly dataCitation signal: 164

observational

Interventions that reduce hepcidin production combined with dietary strategies to increase iron intake may be important means of improving iron status in women with depleted iron stores.

Iron

Evidence score: 58.7|Caution index: 1.3

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