Other name(s):

a,e-diamino-n-caproic acid

General information

Lysine is an essential amino acid. It’s needed to help make protein. It’s also needed to break down carbohydrates and fatty acids. 

Unsubstantiated claims

There may be benefits that have not yet been proven through research.

Lysine may slow or stop the growth of viruses. It may protect against sexual transmission of the herpes virus. It may prevent cold sores (herpes sores) from coming back when taken with vitamin C and bioflavonoids.

Lysine may improve how calcium is used. It may aid in bone growth and healing. Lysine may also prevent fatigue and increase stress tolerance.

Recommended intake

Amino acids (AAs) are available as single AAs or in AA combinations. They also come as part of multi-vitamins, proteins, and food supplements. The forms include tablets, fluids, and powders.

By eating enough protein in your diet, you get all of the amino acids you need.

There are no conditions that increase how much lysine you need.

Side effects, toxicity, and interactions

Using a single amino acid supplement may lead to negative nitrogen balance. This can lessen how well your metabolism works. It can make your kidneys work harder. In children, single amino acid supplements may cause growth problems.

You should not take high doses of single amino acids for long periods of time.

Talk to your healthcare provider before taking lysine if you have diabetes or use medicines to lower your blood sugar. You should talk to your healthcare provider if you have osteoporosis or are using calcium supplements. Lysine may reduce how much calcium you absorb. It may decrease urine loss. 

Women who are pregnant or breastfeeding shouldn’t use lysine supplements.