Shingles is a painful medical condition that is caused by reactivation of the varicella-zoster virus in the body. This virus also causes chicken pox. L-lysine is an amino acid that shows some promise for preventing and treating herpes simplex 1 and 2, two types of a virus that causes genital herpes and cold sores. As of 2011, any relationship between lysine and shingles was believed to be theoretical.

After a person has chicken pox, the varicella-zoster virus remains in the body in a dormant state. For reasons that are unclear, some people experience a reactivation of this virus later in life. Anyone who has had chicken pox might develop shingles, but the condition is more common in older adults and in people who have weakened immune systems.

Shingles most often begins with pain along a nerve line on one side of the body. The pain might be severe. A rash of blisters along this nerve line usually develops as well, but some people who have shingles don't get a rash. Shingles also might involve itchiness, tingling sensations, fatigue, headaches and a fever and chills. The condition resolves on its own, but treatment with prescription antiviral medication can reduce its duration and decrease the risk of complications.

Lysine is an essential amino acid. The body requires this nutrient, and it must be obtained by eating protein-rich foods or taking supplements. In addition to having several important roles for general health, lysine has antiviral effects and prevents herpes simplex 1 and 2 from replicating. Research indicates that outbreaks of genital herpes and cold sores might be reduced or prevented by taking lysine supplements regularly. Taking lysine might also lessen the severity and duration of an outbreak that does occur, but research on this usage had produced conflicting results as of 2011.

The benefits of lysine for people who have herpes simplex has led some doctors to theorize that the amino acid might also be helpful for treating shingles. Herpes zoster is not the same virus as herpes simplex, however, although they are related. As of 2011, research was lacking on lysine and shingles, and no scientific evidence supported using lysine to help treat shingles.

Lysine generally is considered a safe supplement when used on a short-term basis. Standard doses during a herpes simplex flare-up range from 3,000 to 9,000 milligrams per day. To prevent recurrences, people might take 1,000 to 3,000 milligrams per day. Research had not found any relationship between lysine and shingles as of 2011, so the supplement might not help treat the condition, but it likely will not cause harm.

Even if lysine and shingles do have a connection, the condition still calls for medical treatment. Left untreated, shingles can lead to complications, such as a bacterial skin infection. Early treatment with antiviral drugs might prevent a complication known as postherpetic neuralgia, which involves pain that persists long after a case of shingles has been resolved.