Healfast

Indications

L-Lysine HCl is an essential amino acid (a building block of protein that the body cannot make, so it must come from food). It is used as a nutritional supplement when the diet is low in protein, often in syrups and tablets for appetite and growth together with vitamins. Some people also take it to help reduce repeated cold sores, although the evidence for this is limited.

How It Works

Lysine is needed to build body proteins, including muscle and collagen, and helps the gut absorb calcium. It is also used to make carnitine, which helps the body turn fat into energy.

Dosage and Administration

Adults, as a supplement: usually 500 mg to 1 g a day, or as directed on the product or by the doctor. Combination syrups and children's products: follow the label or the doctor's advice; for children the dose depends on age. Take by mouth, preferably with water before or with meals.

Interactions

• Lysine increases calcium absorption; people taking high-dose Calcium supplements should check with a doctor.
• Take care with medicines that can harm the kidneys, such as Gentamicin and other aminoglycoside antibiotics; ask the doctor before using high doses of lysine with them.

Contraindications

• Allergy to lysine or any ingredient of the product.
• Rare inherited disorders of lysine handling, such as lysinuric protein intolerance.

Side Effects

Usually well tolerated at normal doses. Occasionally stomach pain, nausea or diarrhoea, especially with high doses.

Get urgent medical help if you have signs of a serious allergic reaction, such as swelling of the face, lips or throat, difficulty breathing, or a widespread rash.

Pregnancy and Lactation

Lysine from normal food is safe. There is not enough information on high-dose supplements in pregnancy or breastfeeding, so use them only if a doctor advises.

Precautions and Warnings

• People with kidney or liver disease should use lysine supplements only on medical advice.
• Do not take more than the recommended dose for long periods.
• A supplement does not replace a balanced diet; poor appetite or poor growth in children should be checked by a doctor.

Overdose

Very large amounts may cause stomach cramps and diarrhoea. Stop taking it and seek medical advice if symptoms are severe or a child has swallowed a large amount.

Therapeutic Class

Amino acid (nutritional supplement).

Storage

Store below 30°C in a dry place, away from light and out of the reach of children. Keep syrup bottles tightly closed.