Lysine is an essential amino acid because the human body cannot synthesize it in the body and therefore its breakdown is irreversible. Lysine is produced by fermentation from carbohydrate sources as a white crystalline powder, odorless but with a slight bitter taste. Lysine is readily soluble in water and practically insoluble in alcohol.

In the pharmaceutical field, lysine (usually in the format of monohydrochloride) is used as a component for integral amino acid preparations and therapeutics for herpes simplex (Griffith, 1987).

In agro-business, lysine is an indispensable component for lifestock feed, especially for pigs and chickens.

In human nutrition, lysine has been recognized as the first limiting essential amino acid in predominantly cereal diets and is inadequate among the poor in most developing regions (Scrimshaw, 1973). A significant improvement in protein quality by lysine fortification and a subsequent enhancement of growth in children has been documented in ethnically and culturally diverse populations living on diets marginally deficient in lysine (Pellet & Ghosh, 2004; Hussain, 2004; Zhao, 2004). Recent studies indicate that requirements for lysine and other essential amino acids may be increased in acute infectious disease states (Kurpad, 2003, Smriga, 2004). The most recent human studies in Western African showed that dietary supplementation with lysine could reduce diarrheal morbidity in children and respiratory morbidity in men (Ghosh, 2010). One of the ICAAS member companies is actively pursuing research and development in Western Africa, building upon the above clinical data (Fig.)

In respect to upper levels in human diet, few data indicate adverse effects caused by lysine ingestion (the 6th ICAAS Workshop on the Assessment of Adequate Intake of Dietary Amino Acids). In the US population, the main intake of lysine from foods was 5.3 gram per person per day. The scientific literatures contain several studies with added doses of approximately 3 – 6 gram free lysine per day in herpes simplex treatment, without any side effects reported.

Most of the lysine intake from dietary supplements is in the form of a hydrochloride. Because high chloride intake may induce hyperchloremic acidosis, which is deleterious in patients with renal failure who cannot handle excessive loads of acids, a certain attention to chloride intake in that subgroup of people is warranted. However, The presently available literature indicates that there are no clear hazards identified for an excessive dietary intake of lysine and that a metabolic limit could be the only real approach to setting up an upper limit (if one is needed). This approach would be in parallel to the FAO/WHO Nutrient Risk Assessment Workshop approach which proposed the use of the highest observed intake concept for endogenous substances with no known adverse health effects.


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