Lysine description

Lysine is an essential amino acid, which means that it cannot be produced by the body and must be obtained from food.

It is concentrated in muscles and is involved in many biological functions.

It contributes to bone growth, collagen and antibody formation, and carbohydrate metabolism.

It is chemically close to arginine, another amino acid with which it competes in the body.

When isolated, it appears as a white, odourless, slightly salty, water-soluble, microcrystalline powder.

It is widely used in animal feed, particularly in poultry and pig production.

Commercial supplements are only available in capsule or tablet form, usually containing 500 mg to 1 g of lysine each.

Ointments or lip balms containing lysine are also available.

Infant formula, meat substitutes, protein supplements and meal replacements usually contain lysine mixed with other amino acids.

Indications

Possible efficacy

• Reduce the intensity and recurrence of fever blisters outbreaks and accelerate healing.
• Dosage: 1g to 3g daily

Food sources

Meat, fish, eggs and dairy products are very rich in lysine, but it is also found in pulses, especially soya beans.

Maize and fermented products (e.g. sauerkraut, miso) also contain it.

Lysine deficiency

Lysine deficiency is extremely rare in the developed world, where the estimated intake is 6-10g per day, although 1g per day would be sufficient for most people.

Burn victims and athletes who train intensively may need more than 1g per day.

Intense stress or malnutrition can even lead to lysine deficiency, which can cause a drop in immune defences, anaemia and stunted growth.

Precautionary measures

Caution

If you are taking lysine for the herpes virus, you should avoid foods high in arginine such as chocolate, peanuts, nuts and seeds and, to a lesser extent, sprouted wheat. These foods can reduce the beneficial effects of lysine.

People with liver disease or chronic kidney disease should consult their doctor before taking lysine supplements.

Contraindications

Hyperlysinemia (a rare genetic disorder).

Adverse effects

At the doses recommended here, adverse effects are rare.

Lysine supplements may cause nausea, cramps and diarrhoea at doses of 10g or more per day.

Interactions

With plants or supplements: if you are taking lysine for herpes, avoid supplements containing arginine as they may reduce the effect of the treatment.

With medicines: in theory, the effects of a lysine supplement could be added to those of medicines that have a toxic effect on the kidneys, such as aminoglycoside antibiotics.