The Health Benefits of Lysine

Can Lysine Help to Heal Cold Sores?

Lysine capsules, tablets, beans, eggs, and nuts

Verywell / Anastasia Tretiak

Lysine is an essential amino acid thought to help the body produce infection-fighting antibodies, enzymes, hormones, and body tissues. Also known as "L-lysine," lysine supplements are touted as a natural remedy for a number of health problems, including cold sores (herpes simplex labialis), genital herpes, and shingles.

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.

Health Benefits

Lysine supplements are sometimes used to treat a wide range of conditions, including:

  • Canker sores
  • Diabetes
  • High triglyceride levels
  • Improved muscle strength and athletic performance
  • Bedsores
  • Schizophrenia

So far, there is not enough clinical evidence to support these benefits.

However, 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:

Cold Sores

Some studies suggest that lysine supplements may reduce the severity and duration of cold sore outbreaks by keeping the herpes simplex virus from replicating, however a 2017 review said that there was not enough evidence to support its use in preventing cold sore outbreaks.

In research studies, oral lysine is typically taken in doses of 1000-1248 mg per day. However, some clinical research suggests that lysine may not help.

A 1984 study, published in Archives of Dermatology, explored the use of oral lysine supplements (400 mg, three times per day) in a group of 21 patients with recurrent herpes simplex infection but did not find a substantial benefit of lysine treatment for prevention or treatment.

A 2015 analysis of randomized controlled trials of interventions for the prevention of herpes simplex labialis did not find any evidence for the effectiveness of lysine.

Topical application of a lysine ointment has also been explored for herpes simplex infections. 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- and zinc oxide-based ointment (called Super Lysine Plus +) applied topically every two hours. By the sixth day of treatment, cold sore symptoms were resolved in 87% of patients. When left untreated, cold sores may last up to 21 days.


For a report published in 2010, researchers looked at 24 studies on the use of dietary supplements in the 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.


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.

Possible Side Effects

Lysine supplements are possibly safe for most people when taken by mouth in appropriate doses for up to one year or when applied to the skin for up to one year. Side effects stomach pain and diarrhea.

Certain people should avoid the supplement. There is not enough evidence to know if it is safe for women who are pregnant or breastfeeding. Also, those with kidney disease, intolerance to lysinuric protein, or osteoporosis should speak to their healthcare provider when taking the supplement.

Eggs, nuts, and beans

Verywell / Anastasia Tretiak

Dosage and Preparation

Various doses have been studied in research, and as of yet, there is no standardized recommended dose of lysine used topically or in supplemental form.

For cold sores, an oral dose of 1000 mg daily for up to 12 months, or 1000 mg taken three times daily for six months has been used. For cold sore prevention, a dose of 500-1248 mg taken daily or 1000 mg taken three times daily has been used.

Doses applied to the skin vary.

What to Look For

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. Your healthcare provider can provide recommendations regarding dose and proper use.

When you buy a lysine supplement, (or any dietary or herbal supplement) the National Institutes of Health (NIH) recommends that you look for a Supplement Facts label on the product that you buy. This label will contain vital information including the amount of active ingredients per serving, and information about other added ingredients.

Lastly, the organization suggests that you look for a product that contains a seal of approval from a third party organization that provides quality testing. These organizations include U.S. Pharmacopeia,, and NSF International. A seal of approval from one of these organizations does not guarantee the product's safety or effectiveness but it does provide assurance that the product was properly manufactured, contains the ingredients listed on the label, and does not contain harmful levels of contaminants.

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Article Sources
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Additional Reading
  • 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.

  • 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.

  • 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.