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L-Lysine Tablets for Cold Sores

author image Barbara Froek
Barbara Froek is a dietitian and fitness trainer who holds a Bachelor of exercise and nutrition sciences as well as a Master of dietetics, food and nutrition. She has served as a contributing writer for various diet and fitness magazines including "Flex," "Muscular Development" and "Muscle & Fitness Hers."
L-Lysine Tablets for Cold Sores
A woman covering her mouth with her hand. Photo Credit dolgachov/iStock/Getty Images

Cold sores are caused by a virus that triggers blisters to form on and around your lips. They can be painful and unsightly, and currently there is no cure. Cold sores typically clear up within a couple of weeks without treatment, and over-the-counter options are available. However, data suggest lysine may help manage cold sore outbreaks.

The Dreaded Cold Sore

A cold sore goes through five stages. Initially you may feel a tingling sensation before blisters appear. This is called the prodome stage, and it lasts one to two days. After that, blisters begin to appear -- a stage that lasts about two days . Then the blisters break open, which is called the weeping stage -- the most contagious stage. The weeping stage lasts one day and is followed by the scabbing stage, where the blisters scab over. Lastly, the scab falls off and the cold sore is healed.

Lysine 101

Lysine is an amino acid, or building block of protein, that your body needs but can't make on its own, so intake from food or supplements is necessary. Lysine plays various roles in health, promoting energy and helping your body absorb calcium. If you don't have enough, you may start to feel tired and run down. Protein-rich foods such as meat, dairy, eggs and beans offer a good source of lysine. Lysine is also available as a supplement in the form of tablets, capsules, creams and liquids.

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Supportive Clinical Evidence

Lysine possesses antiviral properties and reduces the rate at which herpes, the virus that causes cold sores, multiplies, according to a review published in the journal "Cutis" in July 2005. Researchers reviewed existing clinical data and found evidence that taking 1,000 milligrams of lysine reduces the duration and frequency of cold sore outbreaks. They also found evidence suggesting a higher blood level of lysine is linked to fewer recurrent outbreaks.

Lysine Dosage and Precautions

To prevent cold sore recurrences, it's common to take 1,000 milligrams of lysine per day, according to the University of Maryland Medical. During a flare-up, many people temporarily take doses of 3,000 to 9,000 milligrams in divided doses each day. Lysine may interact negatively with medications that contain arginine and certain antibiotics such as neomycin and streptomycin. Consult your doctor before taking lysine supplements if you have kidney disease.

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