Does Xerese Work for Cold Sores?
Xerese, a prescription cream combining 1% acyclovir and 1% hydrocortisone, treats recurrent herpes labialis (cold sores). Clinical trials show it shortens healing time by about half a day compared to placebo—median 4.3 days versus 4.8 days—and reduces pain duration.[1] It performs similarly to acyclovir alone but adds hydrocortisone to ease inflammation and itching faster.[2]
How Quickly Does It Start Working?
Apply every 3 hours (up to 6 times daily) for 1 day only, starting at the first tingle or blister. Symptoms improve within 24 hours for many; full crusting and healing follow in 4-5 days. Vehicle control (cream base) alone heals in about 5 days, so the combo edges it out modestly.[1][3]
Who Sees the Best Results?
Most effective in adults with frequent cold sores (6+ episodes/year). Trials excluded immunocompromised patients or those with genital herpes. Kids under 12 and pregnant/nursing people should avoid it due to limited data.[2][4] Success drops if started after blisters fully form.
What If It Doesn't Work for Me?
About 20-30% of users report no difference from placebo in some studies, often due to late application or viral resistance. Alternatives include oral valacyclovir (faster, 1-2 day healing) or over-the-counter docosanol (Abreva).[5] Persistent sores warrant a doctor's check for complications like bacterial infection.
Common Complaints and Side Effects
Mild skin irritation (dryness, redness) hits 5-10% of users; serious reactions are rare. Hydrocortisone risks skin thinning with overuse, but 1-day dosing minimizes this. Patients note it stings on open sores.[2][4]
[1]: FDA Label for Xerese
[2]: Xerese Clinical Trial Data (Spruance et al., Antimicrob Agents Chemother, 2006)
[3]: Drugs.com Xerese Reviews
[4]: Medscape Xerese Overview
[5]: Cochrane Review on Topical Antivirals for Cold Sores