Lysine is an essential amino acid needed for growth and to help maintain nitrogen balance in the body. (Essential amino acids cannot be made in the body and must be supplied by the diet or supplements.) It may help promote proper nitrogen balance in the body and prevent glycosylation, the combining of a sugar and protein molecule accelerated by elevated levels of sugar in the blood.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.Most people, including vegans (vegetarians who also avoid dairy and eggs), consume adequate amounts of lysine. However, vegans whose diets contain large amounts of grains and only minimal amounts of beans could become deficient in lysine. Athletes involved in frequent vigorous exercise have increased need for essential amino acids, although most diets meet these increased needs. The essential amino acid requirements of burn patients may exceed the amount of lysine in the diet.Lysine supplementation increases the absorption of calcium and may reduce its excretion. Lysine works with other essential amino acids to maintain growth, lean body mass, and the bodys store of nitrogen.