Zinc is one of the most over-claimed and under-understood supplements on the UK pharmacy shelf. Lozenges for colds. Tablets for acne. Creams for nappy rash. Syrup for taste loss. The marketing has raced ahead of the clinical evidence in places, and a structured pharmacy-counter conversation often needs to walk a customer back to what is actually supported.
This piece summarises what the Cochrane and UK regulatory evidence say about zinc in 2026, where it is a reasonable pharmacy recommendation, and where the honest answer is "probably won't help".
The three questions patients actually ask
In UK community pharmacy, zinc enquiries cluster around three use cases:
- Preventing or shortening a cold — typically around the start of winter or when someone in the household is unwell.
- Wound healing and skin — ulcers, slow-healing skin, acne, nappy rash.
- Taste and smell disturbance — often after a viral infection, and occasionally after courses of certain drugs.
The evidence for each is different.
Zinc and the common cold
The often-cited claim is that zinc lozenges shorten a cold. The evidence, drawn largely from randomised trials of zinc acetate and zinc gluconate lozenges, suggests a modest and variable effect.
The Cochrane review on zinc for the common cold found low-certainty evidence that zinc lozenges taken within 24 hours of symptom onset may reduce the duration of the common cold by a modest amount in adults — on the order of a day or two in some analyses, not at all in others. The reviewers noted heterogeneity between trials, doses and formulations, and flagged that the effect is neither large nor consistent.
Practical points for the counter:
- The evidence, such as it is, applies to lozenges, not tablets or syrups, and only when started very early in the illness.
- Doses studied were typically around 75 mg elemental zinc per day, split across multiple lozenges. This is well above the NHS recommended daily intake (about 9.5 mg for adult men, 7 mg for adult women).
- Nausea, bad taste and mouth irritation are common at these doses.
- There is no good evidence that routine zinc supplementation prevents colds in healthy adults.
A reasonable recommendation is: if a customer wants to try zinc lozenges and has been unwell for under 24 hours, the likely downside is tolerability rather than harm. It is not a product to recommend as cold prevention through the winter.
Zinc and wound healing
Zinc has a legitimate physiological role in collagen synthesis and epithelial repair. That has led to decades of use in leg ulcer dressings, nappy rash creams and burns care. The underlying story is more nuanced than "zinc heals wounds".
The evidence supports:
- Zinc oxide topical preparations as barrier creams in nappy rash, pressure-area protection and minor skin irritation. The BNF listing for zinc oxide reflects this.
- Oral zinc in confirmed zinc deficiency, particularly in malnutrition, extensive burns or chronic enteropathy, where dietary intake is inadequate. Repletion restores normal healing.
The evidence does not clearly support oral zinc supplementation for wound healing in adults with normal zinc status. Cochrane and UK tissue-viability reviews have repeatedly failed to find a convincing benefit in venous leg ulcers, pressure sores or surgical wounds unless the patient is deficient to start with.
For a healthy adult with a slow-healing cut asking about zinc, the honest counter answer is: a topical barrier and good dressing practice will usually do more than an oral supplement.
Zinc and taste disturbance
Taste loss has become a more frequent pharmacy enquiry since the COVID era. Zinc deficiency can genuinely cause dysgeusia, and repletion can restore taste where a true deficiency exists. Outside that niche, oral zinc has not been convincingly shown to restore taste after viral infection or in idiopathic dysgeusia.
Trials of zinc for COVID-related smell and taste disturbance have been small, short and mostly negative. Current advice is to avoid over-promising across the counter: olfactory training, time and — where symptoms persist — ENT assessment remain the pillars of post-viral recovery, not zinc tablets.
Safety and the UK upper limit
The UK Expert Group on Vitamins and Minerals set a guidance level of 25 mg/day of supplemental zinc for adults, on top of dietary intake. The US Institute of Medicine upper limit is 40 mg/day total.
Why it matters:
- Long-term intake above 50 mg/day of elemental zinc can cause copper deficiency, which presents as anaemia and, over years, neurological change.
- Acute high doses cause nausea and bad taste.
- Denture fixative abuse is a rare but recognised cause of zinc-induced myelopathy.
The typical cold-lozenge regimen (around 75 mg/day elemental zinc) is short-term and tolerated, but people who take zinc tablets for months on end should be asked about dose and duration. A customer on 50 mg elemental zinc daily for a year is at real risk of copper deficiency.
| Scenario | Typical UK pharmacy product | Evidence basis |
|---|---|---|
| Cold within 24 h of onset | Zinc acetate/gluconate lozenges ~15 mg, up to 6/day | Low-certainty Cochrane evidence of modest duration reduction |
| Nappy rash / minor skin | Zinc oxide 15% ointment | Long-established barrier use |
| Dietary insufficiency / vegan | Zinc citrate/gluconate 10–25 mg tablet | RDA top-up; avoid long-term high doses |
| Wound healing in a well adult | No supplement indicated | Evidence weak outside deficiency |
| Taste loss post-virus | No supplement indicated | Evidence weak outside confirmed deficiency |
Interactions worth remembering
- Tetracyclines and quinolones: zinc binds these antibiotics in the gut and can reduce absorption. Separate doses by 2–3 hours.
- Penicillamine: zinc reduces absorption.
- Thiazide diuretics: long-term can increase urinary zinc loss.
- Iron supplements: compete for absorption when taken together — not necessarily harmful, but efficacy of both is reduced.
Further reading on PharmSee
- Vitamin B12 supplements at the pharmacy: cyanocobalamin, methylcobalamin and who needs them
- Magnesium supplements at the pharmacy: types, uses and evidence
- Probiotics at the pharmacy: IBS, antibiotics and the evidence
Find a UK community pharmacy on PharmSee.
Sources and caveats
Content drawn from the Cochrane review on zinc for the common cold, BNF entries for zinc sulfate and zinc oxide, NHS guidance on vitamins and minerals, and the UK Expert Group on Vitamins and Minerals. This article is general information for UK community pharmacy use, not personalised medical advice.