Mineral supplements. Trace elements
ATC code: A12CB-ZINC (Zinc (oral salts, generic group))
Brand names – drugs
Galzin, Wilzin
Brand names – supplements
Cold-Eeze, Thorne Zinc Picolinate, Jarrow Formulas Zinc Balance
Supplements are not tested in clinical trials and are not registered as medications.
Zinc is a structural and catalytic cofactor for more than 300 enzymes, including carbonic anhydrase, alcohol dehydrogenase, and DNA polymerases. A structural component of zinc-finger transcription factors. Required for immune function, wound healing, thyroid hormone synthesis, and male reproductive function. In Wilson disease, zinc blocks intestinal copper absorption by inducing metallothionein in enterocytes.
First line
Zinc acetate (Wilzin, Galzin) or zinc sulphate is maintenance therapy for Wilson disease after the initial copper chelation phase. Dose: 50 mg elemental zinc three times daily. Included in EASL 2012 and AASLD 2023 guidelines as maintenance therapy. In asymptomatic ATP7B mutation carriers, it is first-line therapy. The effect develops over 4–8 weeks and requires lifelong use.
Used in specialised hepatology centres; not for self-prescription.
First line
Oral zinc is first-line for confirmed zinc deficiency. Adult doses are 25–50 mg elemental zinc daily for 1–3 months with plasma zinc monitoring. In children with diarrhoea in developing countries, WHO recommends 10–20 mg zinc daily for 10–14 days – this approach reduces diarrhoea duration and recurrence. After bariatric surgery, in cystic fibrosis, Crohn disease, or parenteral nutrition, lifelong deficiency correction is required.
Individual decision
Evidence is mixed. The 2013 Cochrane review (Singh & Das, 18 RCTs, around 2,000 participants) in adults found a 1–1.5 day reduction in cold duration with zinc lozenges or syrup at 75 mg elemental zinc daily, started within 24 hours of symptom onset. Zinc as **prevention** (continuous intake to avoid new URI episodes) has not reproduced its effect in large RCTs. The AAP does not recommend zinc for colds in children – the modest clinical benefit does not justify side effects: nausea, unpleasant taste, diarrhoea. CDC and NICE do not include zinc in URI management standards. Intranasal zinc has been withdrawn due to irreversible smell loss.
Efficacy critically depends on zinc form (lozenges or syrup, not tablets), dose, and timing. Starting later than 24 hours from symptom onset gives minimal effect. International societies do not support use in children.
Not recommended
The 2020 Cochrane review rated the effect of oral zinc on acne as limited in evidence volume and quality. Weak positive results for inflammatory acne in small RCTs. International dermatology guidelines (AAD, EAD) do not include zinc as first-line therapy. Topical zinc combined with erythromycin has a separate evidence base.
Not recommended
Zinc for ageing prevention, dementia prophylaxis, or longevity is not mentioned in international guidelines. AREDS and AREDS2 trials in age-related macular degeneration showed an effect of the zinc-antioxidant combination on disease progression – but this is a narrow ophthalmology indication, not general anti-ageing.
Long-term zinc intake above 50 mg daily induces metallothionein synthesis in enterocytes, which binds copper and blocks its absorption. Copper deficiency develops with anaemia, neutropenia, and myelopathy. With long-term zinc therapy, monitor copper and ceruloplasmin every 6 months or supplement copper 1–2 mg daily.
Safe at physiological doses (RDA 11 mg daily). High doses (above 40 mg daily) in pregnancy are not recommended. Supplementation at the RDA is justified in pregnant vegetarians.
Transfers into breast milk at physiological amounts. Supplementation at the RDA is safe.