Zinc: what the evidence actually shows

settled zinc — established for cold duration at the right dose and timing

Reviewed by Substrate editorial, Independent research collective · 2026-07-16

Evidence by outcome

cold preventiongrade Bmoderate certainty— zinc lozenges started early may modestly shorten cold duration

heart healthgrade Bmoderate certainty— GRADE-assessed meta-analysis of 75 studies: zinc supplementation significantly lowered several cardiometabolic risk markers — triglycerides, total cholesterol, fasting blood glucose, HbA1c, insulin resistance (HOMA-IR), and inflammatory markers (CRP, IL-6, TNF-alpha). A broad risk-factor signal across many biomarkers, not a demonstrated reduction in cardiovascular events.

immune functiongrade Clow certainty— supplementation helps mainly when intake is deficient

skingrade Clow certainty— Acquired zinc deficiency is deeply involved in the development of skin diseases including acquired acrodermatitis enteropathica, necrolytic migratory erythema, alopecia, and delayed wound healing, and mutations or dysregulation in zinc transporters are associated with skin manifestations.

moodgrade Clow certainty— may augment antidepressant response; deficiency-correction likely matters

skingrade Clow certainty— Systematic review and meta-analysis: people with acne tended to have lower serum zinc levels, and zinc treatment modestly reduced acne lesion counts versus control. Trials were heterogeneous in dose and form, so certainty is low.

People say · Evidence shows

“Zinc cures colds”

aheadmodestfolk

Grade history

2026-07-16C → CSource correction by Claude (b2 garbage-source correction): replaced an off-topic search-fallback source (published before the pump's topica details →
2026-07-16C → CCorrection by Claude (gold-standard provenance sweep): live Postgres source drift replaced with the verified seed source set [pmid-29186856] details →
2026-07-16B → BCorrection by Claude (gold-standard provenance sweep): live Postgres source drift replaced with the verified seed source set [pmid-23775705] details →

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

By outcome — the money pages

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Is Zinc hype?

sources: PMID:23775705 · PMID:37399684 · PMID:29186856 · PMID:29439479 · PMID:32829928 · PMID:32860489

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Reuse under CC-BY 4.0 with attribution to evidencebased.info.

Plain-text citation

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

BibTeX

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