For years, lysine has been considered in the treatment of herpes and cold sores, and more recently, has been attracting attention as a possible addition to the fast-growing list of muscle-building nutrients.
L-Lysine is a necessary building block for all protein in the body. L-Lysine plays a major role in calcium absorption; building muscle protein; recovering from surgery or sports injuries; and the body's production of hormones, enzymes, and antibodies.
Lysine appears to help the body absorb and conserve calcium. Lysine has many functions in the body because it is incorporated into many proteins, which are used by the body for a variety of purposes. Lysine interferes with replication of herpes viruses and is therefore often prescribed by doctors to people with cold sores or genital herpes. A review of the research trials investigating the effects of lysine on people with cold sores shows that most, though not all, trials support the use of lysine.
Brewer's yeast, legumes, dairy, fish, and meat all contain significant amounts of lysine. Most people, including vegans (vegetarians who also avoid dairy and eggs), consume adequate amounts of lysine. Athletes involved in frequent vigorous exercise have an increased need for essential amino acids.
Taking normal amounts of Lysine, no consistent problems have been reported in humans, though abdominal cramps and transient diarrhea have occasionally been reported at very high intakes of 15 - 40 grams.
Lysine supplementation has been shown to increase the absorption of calcium and it may reduce its excretion. Some researchers believe that lysine may be shown to have a role in the prevention and treatment of osteoporosis. Lysine works with other essential amino acids to maintain growth, lean body mass, and the body's store of nitrogen.