Overview:

Lysine, or L-lysine, is an essential amino acid, which means that it is necessary for human health but cannot be made by the body. For this reason, lysine must be obtained from food. Amino acids are the building blocks of protein. Lysine is important for proper growth, and it plays an essential role in the production of carnitine, a nutrient responsible for converting fatty acids into energy and helping to lower cholesterol. Lysine appears to help the body absorb and conserve calcium, and it plays an important role in the formation of collagen, a substance important for bones and connective tissues including skin, tendon, and cartilage.

If there is too little lysine in the diet, kidney stones and other health related problems may develop including fatigue, nausea, dizziness, loss of appetite, agitation, bloodshot eyes, slow growth, anemia, and reproductive disorders. It is extremely rare, however, to obtain insufficient amounts of lysine through the diet. Generally, only vegetarians who follow a macrobiotic diet and certain athletes involved in frequent vigorous exercise are at risk for lysine deficiency. For vegetarians, legumes (beans, peas, and lentils) are the best sources of lysine.

Lysine is involved in the browning reaction, or carmelization, in foods such as pastries, doughnuts, cookies, and cereals. In this process, lysine and sugar become linked together in a way that makes lysine difficult for the body to absorb. As a result, a diet high in cereals and baked goods, especially those that contain a lot of simple sugars, can result in low lysine intake.

Uses:

Herpes and Shingles

L-lysine can be used to treat mouth and genital lesions caused by herpes simplex virus as well as shingles caused by herpes zoster viruses. Taking lysine supplements can speed recovery time and reduce the chance of recurrent breakouts of the herpes infection.

Osteoporosis

L-lysine helps improve the absorption of calcium from the digestive tract and prevent loss of calcium in the urine. In so doing, some researchers speculate that L-lysine may help prevent bone loss associated with osteoporosis. In addition, laboratory studies suggest that L-lysine in combination with L-arginine (another amino acid) increases the activity of bone-building cells and enhances production of collagen.

Other

Certain forms of lysine and lysine bound to anti-inflammatory medications (such as ibuprofen, or Advil) may help alleviate pain following an episiotomy (a procedure performed during labor that involves cutting the vaginal area to enlarge the vaginal opening and facilitate delivery). These forms of lysine may also relieve migraine headaches and painful periods. Whether L-lysine and other readily available lysine supplements also offer these benefits is not known.

Dietary Sources:

Good sources of lysine are foods rich in protein, including meat (specifically red meat, pork, and poultry), cheese (particularly parmesan), certain fish (such as cod and sardines), nuts, eggs, soybeans (particularly tofu, isolated soy protein, and defatted soybean flour), spirulina, and fenugreek seed.

Available Forms:

Lysine is available in tablets, capsules, creams, and liquids, and is usually sold in the L-lysine form.

How to Take It:

A health care provider can help determine whether your diet provides enough lysine. If your diet does not contain sufficient lysine, a health care provider may recommend lysine supplements as part of a complete amino acid replacement. Do not use lysine in children less than 2 years of age unless under the supervision of a health care provider.

Pediatric

For children ages 2 - 12: Recommendations are 23 mg/kg/day or 10 mg per pound of body weight daily.

Adult

For adults ages 13 and older: Recommendations are 12 mg/kg/day.

For adults with herpes viral infections: To treat symptoms, take 3,000 – 9,000 mg per day in divided doses. To prevent recurrences, take 500 – 1,500 mg per day in divided dosages.

Precautions:

Because of the potential for side effects and interactions with medications, dietary supplements should be taken only under the supervision of a knowledgeable health care provider.

Possible Interactions:

If you are currently being treated with any of the following medications or supplements, you should not use lysine supplements without first talking to your health care provider.

Arginine -- Arginine and lysine share common pathways in the body. Therefore, excess arginine may lower lysine levels in the body.

Alternative Names:

Amino acid K; L-lysine