topical · for cold sores
Zinc Sulfate Topical Gel
Reviewed by the Nimbera editorial team · Last updated May 2026
How to use
Apply a 0.25-0.5% zinc sulfate solution or gel to the cold sore at the first sign of tingling and continue 4-6 times daily until healed. Zinc oxide-based lip balms with SPF can also be used preventively on UV-exposed lips.
How it works
Zinc ions interfere with HSV-1 surface glycoproteins required for host-cell attachment and entry, and may inhibit viral thymidine kinase activity. Zinc also supports the local skin immune response and has mild astringent and antiseptic properties.
Where to buy
Pharmacies carry zinc sulfate solution and zinc oxide ointment. Zinc-containing lip protectants with SPF (e.g. Blistex Medicated) are widely available.
Typical cost: $5-$15 per tube or bottle
Safety notes
Topical zinc at concentrations above 2% can cause local irritation. Avoid contact with eyes. Zinc oxide is safe for lip use; zinc sulfate solutions in higher concentrations should not be ingested. Do not apply to broken or deeply eroded sores without medical advice.
Drug & supplement interactions
- Always tell your doctor or pharmacist about any supplements you take.
- Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
- Herbal remedies can affect how the body absorbs or metabolises drugs.
- Check drugs.com interactions checker before starting.
Clinical source
Kneist W et al., Clinical double-blind trial of topical zinc sulfate for herpes labialis recidivans, Arzneimittelforschung, 1995This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.