Expert Advice

I get cold sores when the season changes. Is there anything I can do to prevent this?

Zinc oxide and lemon balm ointments can treat cold sores: lysine supplements can prevent outbreaks.

I get cold sores when the season changes. Is there anything I can do to prevent this?
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Cold sores are caused by the herpes virus, which lies dormant in your nerve cells until you have an outbreak (a reactivation of the virus and sores). Although you can't get rid of the herpes virus once you have it, you can reduce your chances of an outbreak, which may be triggered by a change in the weather, sun exposure, stress, menstruation, dental work, or trauma.


To prevent cold sores, take a supplement containing the amino acid lysine, which works by competing with the amino acid arginine; the herpes virus needs arginine to replicate itself, so a higher ratio of lysine to arginine means fewer cold sores. Take 1,000 milligrams per day to prevent cold sores or to reduce the severity and duration of outbreaks. Studies have shown that it's safe to take lysine for at least one year, but it's not clear if there are any risks to taking it for longer. If you have kidney damage, don't take lysine.


To treat cold sores, try a lemon balm ointment that contains a 70:1 concentration, like Enzymatic Therapy Cold Sore Relief, and apply it directly to the sore four times per day. Zinc oxide creams like Novitra can also reduce the severity of cold sores—look for a 0.3 percent concentration of zinc oxide, and apply the cream every two hours. Diaper rash creams contain zinc oxide, but at a much higher concentration. They can also work, but use caution if you are prone to hyperpigmentation, which can occur when zinc oxide is applied to open wounds.


For tougher measures, get a prescription for an antiviral medication like Zovirax or Denavir. It can reduce the duration, severity, and frequency of cold sore outbreaks; a good choice if you have more than six outbreaks per year. Topical creams like Denavir have fewer side effects than oral medications like Zorivax, but both are safe. It's also safe to combine them with lysine. No matter which remedy you choose, use it at the first sign of a cold sore for best results.


—Astrid Pujari, M.D., internist and medical herbalist at the Pujari Center in Seattle

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