What Is It?
Lysine is one of numerous amino acids that the body needs for growth and tissue repair. It is classified as one of the nine “essential” amino acids because you need to get it from outside sources such as foods or supplements–in other words the body can’t make it on its own.
Like all amino acids, lysine functions as a building block for proteins. It’s also a key player in the production of various enzymes, hormones, and disease-fighting antibodies.
Many foods supply lysine, but the richest sources by far include red meats, fish, and dairy products (milk, eggs, cheese). Vegetables, on the other hand, are generally a poor source of lysine, with the exception of legumes (beans, peas, lentils).
There is currently no official recommended dietary allowance (RDA) for lysine. It is estimated, however, that the daily requirement for an adult is approximately 12 mg per kilogram (2.2 lb) of body weight. While many people satisfy their need for lysine through dietary sources, supplements are now popular for treating and preventing specific ailments as well.
Researchers are exploring the value of lysine supplementation and the consumption of lysine-rich foods for lowering cholesterol, improving athletic performance, and enhancing recovery after surgery.
Some nutritionally oriented physicians and dentists recommend taking lysine during an outbreak of canker sores to speed healing. The exact cause of these tiny but quite painful mouth ulcers is unclear, but most research indicates that a virus is responsible. However, there have been almost no clinical trials using lysine as a remedy for canker sores.
The most promising application of lysine is its use in managing and preventing painful and unsightly herpes sores caused by the herpes simplex virus (HSV).
Specifically, lysine may help to:
Prevent and relieve cold sores (herpes). Exciting research over the past several decades suggests that lysine may be helpful in controlling herpes simplex-related infections. There are two types of this virus: type 1, which typically causes cold sores or fever blisters around the mouth, and type 2, which tends to cause genital sores. However, both forms can cause eruptions around the mouth or on the genitals. Once infected with the virus, you have it permanently. It may lie dormant, but it doesn’t go away. Outbreaks are usually painful and unsightly, as well as contagious.
A few years ago, researchers discovered that in order to grow (replicate), the herpes virus needs arginine, another common amino acid. (Foods high in arginine include chocolate, peanuts, almonds, seeds, cereal grains, gelatin, and raisins.) Lysine competes with arginine for absorption and entry into tissue cells. And when lysine is present, it inhibits the growth of HSV by knocking out arginine.
This makes a diet high in lysine and low in arginine a useful tool in managing HSV infections. In a recent study, participants consumed large amounts of lysine (about 1 gram three times each day) while restricting food sources of arginine. A significant number of participants (74%) noticed an improvement in their HSV infections and a decrease in the number of outbreaks.
Lysine supplements (as opposed to foods high in this nutrient) can also play an important role in staving off and reducing the severity of herpes-related cold sores. Results of a six-month trial involving more than 50 people indicate that lysine is far more effective than a placebo in preventing cold sores. Participants given a placebo had more than twice as many such infections as those taking lysine. Moreover, the herpes sores that did develop in the lysine group tended to be milder, and to heal faster, than the outbreaks in the placebo group.
Lysine supplements may even prevent HSV outbreaks in chronic sufferers.
Speed healing of shingles lesions. Painful shingles blisters are caused by a reactivation of varicella-zoster virus, an infection that started out as an attack of chickenpox. Herpes zoster is closely related to herpes simplex, however, and lysine appears to have a similar role to play in treating an eruption of shingles. Keep in mind, however, that most nutritionally oriented physicians will combine lysine therapy with conventional antiviral medications such as acyclovir or valacyclovir.
–Of all the amino acids, lysine is the most sensitive to the effects of food processing, such as dry heat. The amount of protein available in legumes and other sources of lysine can be significantly reduced if they have been toasted or roasted.
–Common foods high in lysine include nonfat milk (8 fluid ounces, or 245 grams, contains about 660 mg of lysine) and whole-wheat bread (one slice of wheat bread, or 28 grams, provides 85 mg of lysine).
For canker sores: Take 1,000 mg L-lysine three times a day with meals while a canker sore is present. Reduce the dose to 500 mg three times a day for one week following healing.
For cold sores: Take 1,000 mg L-lysine three times a day with meals for flare-ups. If you are subject to recurrent outbreaks of cold sores, continue on a maintenance dosage of 1,000 mg day.
For shingles: Take 1,000 mg L-lysine three times a day with meals during flare-ups. Reduce the dose to 500 mg three times a day for one week after healing.
Guidelines for Use
For a severe initial outbreak of genital herpes or shingles, see a doctor to confirm that you have the condition and be sure to take one of the prescription antiviral drugs such as acyclovir.
Don’t drink milk at the same time you take lysine.
In very large doses (10 to 30 grams a day), lysine increases the toxicity of aminoglycoside antibiotics, such as gentamicin, neomycin, and streptomycin.
Side effects are rare with lysine supplements, although a few cases of abdominal cramps and diarrhea have been reported with very high doses (more than 10 grams a day).
Canker Sores 500 mg L-lysine 3 times a day
Cold Sores 1,000 mg L-lysine 3 times a day for flare-ups, then 500 mg a day.
Shingles 1,000 mg L-lysine 3 times a day during acute stage; to help prevent recurrences, 1,000 mg a day.
David Edelberg, MD