Q. For years I was plagued with at least two annual bouts of cold sores. One outbreak occurred during a visit to New Zealand. I went to a pharmacy for Zovirax, since it was available there without a prescription.
The pharmacist asked me if I had tried taking L-lysine daily to ward off outbreaks of herpes simplex. I had not. He recommended 500 mg of L-lysine daily. I have taken it for the past 15 years and have not had one outbreak of herpes simplex during that time.
A. Cold sores (herpes simplex 1) are considered a minor nuisance, but a new study has linked such infections to Alzheimer’s disease (Alzheimer’s & Dementia, online, Oct. 7, 2014), as we have discussed in our blog.
Antiviral medications such as acyclovir (Zovirax), famciclovir (Famvir) and valacyclovir (Valtrex) can prevent or shorten an HSV-1 outbreak. We have no idea, however, whether treating cold sores and preventing outbreaks would have any impact on the newly-discovered link to Alzheimer’s disease.
Other readers have found that the amino acid L-lysine can be helpful against cold sores. Here is one reader’s experience:
“In a recent column you answered a question about L-lysine and shingles. I have been taking L-lysine for various forms of herpes for over 20 years, and it has kept me virtually outbreak-free.
“It is also important to avoid nuts and chocolate. Dietary restraint together with L-lysine have worked better for me than acyclovir, which I took for a year as part of a study at the University of Rochester.
“I have read about both nut avoidance and L-lysine, but often when I speak to physicians about it they are not aware of it. A lot of pain and discomfort could be avoided if they were.”
There has been limited research on L-lysine for cold sore prevention, but 30 years ago a placebo-controlled trial of L-lysine against recurrent outbreaks demonstrated a benefit (Dermatologica, 1987).