Zinc for Upper Respiratory Tract Infections
AMeta-analysis of 7 trials demonstrates zinc lozenges at 75+ mg/day may reduce cold duration by 33% when started within 24 hours of symptom onset. Zinc acetate lozenges at 80-92 mg/day showed 40% duration reduction. Doses below 75 mg/day showed no effect.
The Bottom Line
Meta-analysis of 7 trials demonstrates zinc lozenges at 75+ mg/day may reduce cold duration by 33% when started within 24 hours of symptom onset. Zinc acetate lozenges at 80-92 mg/day showed 40% duration reduction. Doses below 75 mg/day showed no effect.
Key Study Findings
Population: patients with post-viral olfactory dysfunction (non-COVID)
Population: None
Population: Elite/professional cyclists nutrition review
Population: Children/adolescents with undernutrition
Population: Children with otitis media
Population: respiratory disease
Key Statistics
15
Studies
1500
Participants
Positive
Grade
Referenced Papers
Dosage & Usage
mg = milligrams · mcg = micrograms (1,000× smaller) · IU = International Units
Commonly Used Dosages
- general:
- 8-11 mg/day
- coldtreatment:
- 75-100 mg/day elemental zinc (lozenges, within 24h of onset, up to 2 weeks)
- immunesupport:
- 15-30 mg/day
Upper limit: 40 mg/day (long-term)
Dosages Studied in Research
| Dosage | Duration | Effect | N |
|---|---|---|---|
| tokishakuyakusan, zinc sulfate, methylcobalamin | -- | Positive | 107 |
| None | -- | Mixed | -- |
| None | -- | Mixed | -- |
| Various oral nutritional supplements | -- | Positive | -- |
| 20 or 30 days treatment | 5 weeks | Positive | 120 |
| 31 μg | -- | Neutral | -- |
| 94.57% | -- | Mixed | -- |
| None | -- | Mixed | 387 |
Best taken: Lozenges: dissolve slowly in mouth every 2-3h at cold onset; Supplements: with food to minimize nausea
Safety & Side Effects
Reported Side Effects
- ⚠ Nausea and vomiting (especially on an empty stomach)
- ⚠ Metallic taste in the mouth
- ⚠ Copper depletion with chronic high-dose use (>40 mg/day)
- ⚠ Headache and diarrhea
Known Interactions
- ● Copper supplements (zinc inhibits copper absorption at doses >40 mg/day)
- ● Tetracycline and quinolone antibiotics (mutual absorption reduction)
- ● Penicillamine (zinc reduces absorption of this rheumatoid arthritis drug)
- ● Iron supplements (mutual absorption interference when taken together)
Tolerable upper intake: 40 mg/day (long-term)
Always consult your healthcare provider before starting any supplement.
Frequently Asked Questions
Does Zinc help with Upper Respiratory Tract Infections?
How much Zinc should I take for Upper Respiratory Tract Infections?
Are there side effects of Zinc?
How strong is the evidence for Zinc and Upper Respiratory Tract Infections?
Related Evidence
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FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. The products and information on this website are not intended to diagnose, treat, cure, or prevent any disease. The evidence grades presented are based on our analysis of published peer-reviewed research and do not constitute medical advice. Always consult your healthcare provider before starting any supplement regimen.