Is Lysine an Effective Treatment for Herpes?

herpes cold sore on face
Herpes Cold Sore on Face. Todd Keith/E+?Getty Images

Question: Is Lysine an Effective Treatment for Herpes?

L-Lysine is an amino acid that is not naturally produced by the human body. Humans get the lysine they need by ingesting food products such as red meats and dairy, and lysine is also available in supplement form. There is a popular belief that lysine is an effective herpes treatment, which can shorten outbreaks or lessen their frequency. Despite this, there is very little scientific evidence that lysine actually affects the course of herpes infections, for either HSV-1 or HSV-2.

Answer: It's Unclear

Trials of lysine for herpes treatment have, by and large, shown inconsistent results. There are questions about whether or not supplementation works at all, and even those studies that have shown a positive effect have led to no standard recommended dose. That having been said, however, there is a theoretical mechanism by which lysine could conceivably work to treat herpes.

In some laboratory studies, lysine has been shown to inhibit the activity of arginine - another amino acid that tends to promote the growth of the herpes virus. If the relative amounts of lysine and arginine in the body do affect herpes symptoms, such as cold sores, then it is understandable why it would be hard to do a study that shows the efficacy of lysine supplementation. People get varying amounts of lysine and arginine in their diets. It would therefore be extremely difficult to modulate their relative amounts via simple supplementation.

There isn't enough data to make me comfortable recommending lysine as a herpes treatment, particularly as compared to more traditional suppressive therapies. However,  if you're taking it and it's working for you then there's no reason to stop. If you're following the directions on the package, lysine is unlikely to harm you, and it may even help.

Just because doctors and scientists don't have enough conclusive evidence to make a general recommendation about lysine doesn't mean it might not be a good adjunct herpes treatment in some people. It's just that there's better evidence for other alternative herpes treatments, including honey!


Chi CC, Wang SH, Delamere FM, Wojnarowska F, Peters MC, Kanjirath PP. Interventions for prevention of herpes simplex labialis (cold sores on the lips). Cochrane Database Syst Rev. 2015 Aug 7;8:CD010095.

Robb-Nicholson C. (2007)"By the way, doctor. For years, I was plagued by cold sores and took antiviral drugs to treat the outbreaks. But at a friend's suggestion, I started taking lysine every day, and it seems to prevent them altogether. What do you know about this supplement?" Harv Womens Health Watch. 14(7):8.

Perfect MM, Bourne N, Ebel C, Rosenthal SL. (2005) "Use of complementary and alternative medicine for the treatment of genital herpes." Herpes. 12(2):38-41. Review.

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