What is the recommended dose of zinc for treating a cold?

Recommended Zinc Dosage for Common Cold Treatment

The recommended dose of zinc for treating the common cold is ≥75 mg/day of zinc acetate or zinc gluconate lozenges, started within 24 hours of symptom onset and continued throughout the duration of the cold. 1, 2

Dosage and Administration Details

• Zinc must be administered as zinc acetate or zinc gluconate lozenges at a dose of at least 75 mg/day for optimal effectiveness 2
• Treatment should begin within 24 hours of symptom onset to maximize benefits 2, 3
• Lozenges should be taken every 2 hours while awake throughout the duration of the cold 4
• The minimum effective dose appears to be 13.3 mg of elemental zinc per lozenge 4, 5

Evidence for Effectiveness

• High-quality evidence shows that zinc significantly reduces the duration of common cold symptoms when administered properly 1
• Studies demonstrate a reduction in median cold duration from 7.6 days to 4.4 days with proper zinc supplementation 4
• Zinc treatment significantly reduces days with specific symptoms including coughing, headache, hoarseness, nasal congestion, nasal drainage, and sore throat 4
• A Cochrane review confirmed that zinc administered within 24 hours reduces cold duration in healthy people 3

Side Effects and Considerations

• Common side effects include bad taste (80% of users) and nausea (20% of users) 4, 3
• Despite these side effects, they are generally well-tolerated and self-limiting 2
• The therapeutic benefits must be weighed against the potential adverse effects 4, 5
• Poor taste may limit patient compliance despite therapeutic benefits 5

Important Clinical Considerations

• Formulation matters: compounds such as citric acid, sorbitol, and mannitol can bind free zinc ions in the mouth, potentially reducing effectiveness 5
• While zinc lozenges at ≥75 mg/day are effective for treatment, there is insufficient evidence to recommend prophylactic zinc supplementation 1
• Lower doses (such as 10 mg zinc combined with vitamin C) have shown less consistent benefits 6
• Some meta-analyses have found conflicting results, highlighting the importance of proper formulation and dosing 7

Common Pitfalls to Avoid

• Starting zinc treatment too late (after 24 hours of symptom onset) significantly reduces effectiveness 2, 3
• Using zinc formulations with binding agents that reduce bioavailability 5
• Discontinuing treatment prematurely before cold symptoms resolve 4
• Using inadequate dosing (less than 75 mg/day) 1