Medically reviewed on Dec 23, 2018
What is Lysine?
Lysine is an amino acid found in the protein of foods such as beans, cheese, yogurt, meat, milk, brewer's yeast, wheat germ, and other animal proteins. Proteins derived from grains such as wheat and corn tend to be low in lysine content. The bioavailability of lysine is reduced with food preparation methods, such as heating foods in the presence of a reducing sugar (ie, fructose or glucose); heating foods in the presence of sucrose or yeast; and cooking in the absence of moisture at high temperatures. The average 70 kg human requires 800 to 3,000 mg of lysine daily.
2,6-diaminohexanoic acid, alpha-epsilon-diaminocaproic acid
What is it used for?
Lysine is an essential amino acid in human nutrition because the body cannot produce it; therefore, it must be taken in either by diet or supplementation. Lysine was first isolated from casein (a milk phosphoprotein) in 1889. It was first introduced in the United States as lysine hydrochloride in 1955. There was an interest in fortifying bread with lysine to target populations with lysine-poor diets. However, the FDA refused to modify the standards of identity for white bread. Since 1970, lysine has been commonly added to animal feed.
Lysine has been studied for the prevention and treatment of herpes infections and cold sores. It also increases the intestinal absorption of calcium and eliminates its excretion by the kidney, suggesting that it might be helpful in osteoporosis. Lysine has been investigated for its effects on increasing muscle mass, lowering glucose, and improving anxiety. Case reports suggest lysine may ameliorate angina. Lysine acetylsalicylate has been used to treat pain and to detoxify the body after heroin use. Lysine clonixinate has been used to treat migraine headaches and other painful conditions. However, limited clinical trials exist for these conditions.
What is the recommended dosage?
Lysine may be dosed from 1 to 3 g daily to prevent or treat herpes simplex infections, reserving the higher dosages for breakouts. In addition to the amount found in the average American diet, L-lysine given at doses in this range appears to be safe for use in adults and prepubertal children.
Lysine supplementation should not be used in patients with too much lysine in the blood or urine. Patients with liver and kidney impairment should avoid supplementation with lysine. If use is warranted, patients should consult a health care provider.
Lysine should be used with caution in pregnancy and lactation.
Use of calcium supplements with lysine may be associated with increased absorption and reduced elimination of calcium. Aminoglycoside toxicity may be enhanced in patients taking lysine supplementation.
GI adverse reactions, such as diarrhea, nausea, and abdominal pain, have been reported with lysine ingestion. A case report described the development of the kidney disorders Fanconi syndrome and tubulointerstitial nephritis associated with lysine supplementation taken over a 5-year period.
High oral doses of lysine are likely to be safe. Doses of 100 mg/kg given to 2 patients with Parkinson disease were not associated with adverse effects.
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