Moderate evidenceImmunity

Zinc

An essential mineral for immune function. Zinc lozenges started at the very beginning of a cold may shorten its duration.

What the science says

Shorter cold duration Moderate evidence
Meta-analyses of trials with zinc acetate lozenges (high doses, started within 24h of symptoms) showed the common cold shortened by about 2–3 days. The form and timing of use matter a lot.
Immune support in deficiency Strong evidence
Zinc deficiency clearly impairs immunity; correcting it restores immune function. Deficiency is more common in older adults, strict vegetarians, and people with intestinal disorders.

Studied doseMaintenance: 8–11 mg/day (daily requirement). For colds, studies used lozenges totaling 75+ mg/day in divided doses, for a few days.

SafetyProlonged use of high doses (>40 mg/day) can cause copper deficiency. Lozenges may cause nausea and altered taste.

Zinc acetate lozenges for treating the common cold: an individual patient data meta-analysis
Hemilä H et al. — British Journal of Clinical Pharmacology, 2016
Zinc for the common cold
Singh M, Das RR — Cochrane Database of Systematic Reviews, 2013

Where to buy

NOW Foods, Zinc, 50 mg, 250 Tablets

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