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Systematic review · The Cochrane database of systematic reviews · 2024Abstract onlyConflicts declared

Zinc for preventing and treating the common cold

Nault D, Machingo TA, Shipper AG, et al · Free full text

What it found

Zinc supplements may make little or no difference to whether you catch a cold, but may shorten a cold you already have.

When used to treat colds, zinc probably increases non-serious side effects like unpleasant taste or stomach upset.

What they found

Studies in people

Catching a cold

There may be little or no reduction in the risk of developing a cold with zinc compared to placebo. The evidence for this was low certainty.

Number of colds

There may be little or no reduction in the average number of colds over five to 18 months of follow-up. The evidence for this was low certainty.

Cold duration with prevention

When colds occur during prevention trials, there is probably little or no difference in how many days the cold lasts. The evidence for this was moderate certainty.

Cold duration with treatment

When zinc is used to treat a cold, there may be a reduction in the average duration of the cold in days. The evidence for this was low certainty.

Symptom severity

There may be little or no difference in global symptom severity when zinc is used for prevention or treatment. The evidence was low to very low certainty.

Side effects

There is probably an increase in the risk of non-serious side effects when zinc is used to treat colds, such as unpleasant taste, loss of smell, vomiting, stomach cramps, and diarrhoea. It is uncertain whether zinc for prevention changes the risk of side effects.

What the authors conclude

“The findings suggest that zinc supplementation may have little or no effect on the prevention of colds but may reduce the duration of ongoing colds, with an increase in non-serious adverse events.”
Nault D, Machingo TA, Shipper AG, et al, 2024

Also in their conclusions

  • They conclude that zinc supplementation may have little or no effect on preventing colds but may reduce the duration of ongoing colds.
  • They note that zinc treatment comes with an increase in non-serious adverse events.
  • They advise that the wide variation in interventions and outcomes across studies, plus incomplete reporting, should be considered when drawing conclusions about zinc for the common cold.

How it was done

Colds are a public health burden and a major cause of lost work and school days. There are no established ways to prevent colds or shorten them, yet zinc supplements are commonly recommended and taken for this purpose.

The authors pooled 34 randomised controlled trials with 8526 participants, including 22 studies in adults and 12 in children. Fifteen trials tested zinc to prevent colds and 19 tested it as a treatment, using lozenges, tablets, syrups, powders, capsules or nasal sprays, mostly in the USA.

What it can’t tell you

  • We summarised it from the abstract only.
  • The evidence for many findings was low or very low certainty, so the results may change with more research.
  • Most studies were at unclear or high risk of bias, which can affect how much we can trust the results.
  • No treatment study provided information on serious adverse events, and no study clearly reported on complications of the common cold.

The paper

Title
Zinc for prevention and treatment of the common cold
Type
Systematic review
Evidence
Studies in people
Summarised from
Abstract only
Cite
Nault D, Machingo TA, Shipper AG, et al (2024). Zinc for prevention and treatment of the common cold. The Cochrane database of systematic reviews. doi:10.1002/14651858.CD014914.pub2Free full textPubMed 38719213DOI

Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error