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Lysine for Cold Sores


Updated June 26, 2013

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Lysine supplements are touted as a natural remedy for a number of health problems, including cold sores, genital herpes, and shingles. Also known as "L-lysine," lysine is an essential amino acid thought to help the body produce infection-fighting antibodies, enzymes, hormones, and body tissues. Proponents claim that lysine supplements can also boost the immune system, as well as aid in muscle repair. Some lysine supplements contain a combination of lysine and L-arginine, another essential amino acid.

The Science Behind Lysine Supplements

Although research on the use of lysine supplements is limited, some studies suggest that lysine supplements hold promise as a treatment for certain health conditions. Here's a look at a few key study findings:

1) Cold Sores

Studies show that lysine supplements and lysine-based ointment may shorten the duration of cold sore outbreaks by keeping the herpes simplex virus from replicating. In a 2005 study of 30 patients, for instance, scientists found that cold sores cleared up in 40 percent of participants after three days of using a lysine-based ointment. By the sixth day of treatment, cold sore symptoms were resolved in 87 percent of patients. (When left untreated, cold sores may last up to 21 days.)

2) Anxiety

For a report published in 2010, researchers looked at 24 studies on the use of dietary supplements in treatment of anxiety. Along with kava and passionflower, a combination of L-lysine and L-arginine was found to be one of the most effective supplements for anxiety relief. Earlier research shows that supplements containing a combination of L-lysine and L-arginine may help alleviate anxiety by normalizing certain hormones involved in the stress response.

3) Osteoporosis

Preliminary research in animals suggests that lysine supplements may increase the body's absorption of calcium and, in turn, protect against bone loss. However, scientists have yet to determine if lysine supplements can help prevent osteoporosis in humans.

Using Lysine Supplements for Health

Most people can get their fill of lysine by following a balanced diet containing high-protein foods (such as nuts, beans, eggs, and soy). If you're interested in using lysine supplements to treat or prevent a specific health problem, make sure to consult your physician before starting your supplement regimen.


Civitelli R, Villareal DT, Agnusdei D, Nardi P, Avioli LV, Gennari C. "Dietary L-lysine and calcium metabolism in humans." Nutrition. 1992 Nov-Dec;8(6):400-5.

Fini M, Torricelli P, Giavaresi G, Carpi A, Nicolini A, Giardino R. "Effect of L-lysine and L-arginine on primary osteoblast cultures from normal and osteopenic rats." Biomed Pharmacother. 2001 May;55(4):213-20.

Shaheen E Lakhan, Karen F Vieira. "Nutritional and herbal supplements for anxiety and anxiety-related disorders: systematic review." Nutrition Journal. October 2010. 9:42doi:10.1186/1475-2891-9-42. 7.

Singh BB, Udani J, Vinjamury SP, Der-Martirosian C, Gandhi S, Khorsan R, Nanjegowda D, Singh V. "Safety and effectiveness of an L-lysine, zinc, and herbal-based product on the treatment of facial and circumoral herpes." Altern Med Rev. 2005 Jun;10(2):123-7.

Smriga M, Ando T, Akutsu M, Furukawa Y, Miwa K, Morinaga Y. "Oral treatment with L-lysine and L-arginine reduces anxiety and basal cortisol levels in healthy humans." Biomed Res. 2007 Apr;28(2):85-90.

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