What is it? Overview Usage Side Effects and Warnings

What is Lysine?

Lysine is an essential amino acid, one that you need to get from food. Some evidence suggests that supplemental lysine may be able to help prevent herpes infections (cold sores and genital herpes).

Some small studies suggest that regularuse of lysine supplements can help prevent flareups of cold sores and genital herpes, although other studies have not found benefit. 1 2 3 4 5 Lysine has also been proposed as a treatment to take at the onsetof a flareup, but at least one study failed to find it effective for this purpose. 6 Both cold sores and genital herpes are caused by a virus called herpes simplex. After you are first infected, this virus hides in certain nerve cells and reemerges under times of stress . Test tube research suggests that lysine fights this virus by blocking arginine , an amino acid the virus needs in order to replicate. 7 For this reason, lysine might be most effective when used in conjunction with a low-arginine diet. ...

Safety Issues

Although lysine is an essential part of the diet, the safety of concentrated lysine supplements has not been well studied. In animal studies, high dosages have caused gallstones and elevated cholesterol levels, 8 so you may want to use caution when using lysine if you have either of these problems. Maximum safe dosages for young children, pregnant or nursing women, or those with severe liver or kidney disease have not been established.

Interactions You Should Know About

If you are taking lysine to treat herpes, arginine might counteract the potential benefit. 9