Iron: what the evidence actually shows

Reviewer and governance status are shown on each atomic claim below.

What it is

Iron is tracked as a health intervention in this evidence graph. No additional aliases are recorded.

Studied forms and doses

No form-specific catalog record is available. This does not mean all forms are equivalent.

energy / fatigue: 18–65 mg/day; form not reported.
cognition: 18–65 mg/day; form not reported.
energy / fatigue: not specified; form not reported.

Mechanisms

Mechanistic plausibility is context, not proof that a clinical outcome improves.

No structured mechanism is recorded.

⚠ Safety in context

No interaction record is modeled for this intervention. This is an unknown coverage state, not evidence that no interaction exists.

Products and verification

No product label snapshot is mapped in this released catalog. Ingredient evidence does not establish any bottle’s identity, potency, purity, availability, or value.

Evidence by outcome

energy / fatiguegrade Ahigh certainty— reliably reduces fatigue when iron deficiency / IDA is present; no benefit when iron-replete

cognitiongrade Clow certainty— improves attention/cognition when iron deficiency is present; no benefit if replete

energy / fatiguegrade Dvery-low certainty— 21-study review: iron supplementation associated with improved fatigue scores (p-values only, no CI/n given) in non-anemic iron deficiency; the review's own meta-analyses were "limited" for most outcomes examined.

People say · Evidence shows

“everyone feels more energetic on iron”

matchesnegligiblefolk

What it probably doesn't do

Iron for energy / fatigue — Grade D, 21-study review: iron supplementation associated with improved fatigue scores (p-values only, no CI/n given) in non-anemic iron deficiency; the review's own meta-analyses were "limited" for most outcomes examined..

Grade history

2026-07-16A → ACorrection by Claude (gold-standard provenance sweep): live Postgres source drift replaced with the verified seed source set [pmid-27087396] details →
2026-07-16C → CCorrection by Claude (gold-standard provenance sweep): live Postgres source drift replaced with the verified seed source set [pmid-35011099] details →

Re-review cadence: every 12 months (Grade A/B) · next scheduled by 2027-07-16 · methodology v1.

By outcome — the money pages

Compare

Is Iron hype?

sources: PMID:27087396 · PMID:35011099 · PMID:26256281

Cite this page

Citation is encouraged. The proposed reuse license is CC-BY-4.0; status: pending-governance-ratification.

Plain-text citation

Substrate. Iron: what the evidence actually shows. https://evidencebased.info/interventions/iron. Updated 2026-07-16.

BibTeX

@misc{substrate_nfointerventionsiron,
  author = {Substrate editorial},
  title  = {Iron: what the evidence actually shows},
  year   = {2026},
  url    = {https://evidencebased.info/interventions/iron},
  note   = {evidencebased.info}
}