Supplement analysis backed by scientific evidence · PT

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Moderate evidenceImmunity

Zinc Acetate Lozenges

The best-studied zinc form for shortening colds, with pooled individual-patient data suggesting roughly a third off the duration. A later randomized trial by the same group found no benefit, so the effect is real but not settled.

Evidence last reviewed: August 2026

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What the science says

  • Roughly one third shorter colds in pooled trials Moderate evidence

    An individual patient data meta-analysis of three randomized trials found that high-dose zinc acetate lozenges shortened the common cold substantially compared with placebo, with the benefit apparent across the symptom course. A separate meta-analysis of the same trials reported faster resolution of nasal, throat and cough symptoms.

  • A later trial found nothing Moderate evidence

    A randomized controlled trial of zinc acetate lozenges in community participants recruited during colds found no significant improvement in recovery rate. This null result from the same research group is a genuine caveat to the pooled estimates.

  • Timing and dose decide the outcome Moderate evidence

    The positive trials used roughly 80–92 mg of elemental zinc per day, begun within about 24 hours of the first symptom. Lower doses and later starts have consistently failed to show an effect.

Dosage & safety

Studied doseLozenges of about 13 mg elemental zinc as zinc acetate, dissolved in the mouth every two to three hours while awake, totalling roughly 80–92 mg per day. Begin within 24 hours of symptoms and stop after about one week.
SafetyUnpleasant metallic taste, nausea and mouth irritation are frequent. This dose is only appropriate for short courses — prolonged intake at this level causes copper deficiency. Separate from tetracycline and quinolone antibiotics by several hours. Avoid intranasal zinc, which has caused permanent anosmia.

Scientific references

Where to buy

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