Lysine

Claims, Benefits: Prevents and relieves cold sores (herpes).

Bottom Line: Though the studies have been inconclusive so far, this amino acid may help head off recurrences of cold sores. Don't take lysine pills daily over long periods, but only when you feel cold sores coming on. For a severe initial outbreak, take one of the prescription drugs, if you can afford it.

Full Article, Wellness Letter, December 1995:

Lysine and cold sores

The herpes virus, an ancient and unwelcome human companion, comes in more than one form. Herpes simplex 1 is almost always the culprit in cold sores or fever blisters that erupt around the mouth; herpes simplex 2 is generally responsible for genital herpes. But, in fact, both forms of the virus can cause eruptions on the genitals and around the mouth. Herpes outbreaks, wherever they occur, are usually painful and unsightly, as well as contagious. Anywhere from 60 to 90% of us carry herpes simplex 1, probably as a result of childhood infection, and genital herpes is one of the most common sexually transmitted diseases these days. (Perhaps 20 million people have genital herpes, and one million become infected each year.) Once you have the virus, you have it. It may lie dormant, but it doesn't go away.

Fortunately, there's now an effective prescription drug for herpes called acyclovir. Sold in capsule, liquid, or ointment form, it does not cure herpes in the sense that antibiotics cure bacterial infections, but it does reduce the severity of outbreaks and seems to have few if any serious side effects. And there's some evidence that long-term daily oral doses can cut down on recurrences. It's also effective against herpes zoster, the chickenpox/shingles virus. (Two similar drugs, one already approved for use against shingles, are soon to be marketed for herpes.) However, acyclovir is quite expensive and there's no generic yet, and many people wonder if there aren't other measures they can take.

About a decade ago, before acyclovir, the amino acid lysine was regarded as a potential herpes treatment. Lysine, one of the building blocks of protein, is supplied by many foods (notably red meats, fish, and dairy products). You can certainly satisfy your needs for lysine from dietary sources. But to fight herpes, you probably need more, the theory ran.

The idea that lysine might work against herpes has some plausibility. In order to replicate, the herpes virus requires arginine, another amino acid that's common in foods and necessary to human life; but lysine is thought to interfere with the absorption of arginine in the intestine. It's a long way from this observation to a herpes cure, and most studies have been inconclusive. A small study conducted at the Baylor College of Dentistry in 1984 did show that lysine supplements-1,000 milligrams a day-helped reduce recurrences of cold sores. (Genital herpes was not part of this study.)

Lysine supplements-worth a try?

For a severe initial outbreak, take acyclovir. Though the evidence is far from strong, lysine supplements might help head off recurrences of cold sores. One caution: no one is sure what the risks are of taking lysine pills daily over long periods. Don't take them continually, but only when you feel cold sores coming on.

Tip for heading off cold sores: sunlight seems to activate herpes simplex 1 in some people. So a sunscreen, applied to the lips daily, can be useful.

UC Berkeley Wellness Letter, December 1995