In addition to prescription antivirual drugs like Acyclovir, heavily promoted treatments include Abreva, Releev and Viroxyn (all relatively expensive at $20 and up). What really matters, of course, is the active ingredient, not the brand name. The active ingredient in Abreva is Docosanol (behenyl alcohol); in Releev and Viroxyn it's benzalkonium chloride, which was found to be more effective than Docosanol in a recent study.
So is benzalkonium chloride a new wonder drug? No, it's the active ingredient in classic Bactine, which has been around since 1950. In other words, inexpensive Bactine is as effective in treating cold sores as these newer, more heavily promoted, more expensive medications.
For best results, cold sores should be treated at the earliest signs, typically a tingling in the skin, and the treatment should be worked into (penetrate) the skin. The drawback to Bactine is that it's a liquid, so working it into the skin is inconvenient, but there are gel products with the same active ingredient that are easy to apply effectively:
- Tecnu First Aid Antiseptic Pain-Relieving Gel ($10 at Walgreens)
Extra strength (0.20% versus standard 0.13%), easily absorbed, recommended.
- Scar Zone Topical Analgesic and Antiseptic Burn Gel ($5.50 at Walgreens)
Standard strength, least expensive.
Tip: Benzalkonium chloride is also effective in treating acne. Acne treatments by Neutrogena with benzalkonium chloride are recommended.