March 21, 2017


Other name(s):

a,e-diamino-n-caproic acid

General information

Lysine is an essential amino acid. It’s needed for the synthesis of protein. It’s also needed for the metabolism of carbohydrates and fatty acids. 

Unsubstantiated claims

Please note that this section reports on claims that have not yet been substantiated through studies.

Lysine has been said to slow or stop the growth of viruses. It may also protect against sexual transmission of the herpes virus. It may prevent the recurrence of cold sores (herpes lesions) if you take it with vitamin C and bioflavonoids.

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

Recommended intake

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

Note that 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 decrease how efficient your metabolism is. It can also make your kidneys work harder. In children, taking single amino acid supplements may also cause growth problems.

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

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

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


March 21, 2017

Reviewed By:  

Poulson, Brittany, RD, CDE,Wilkins, Joanna, R.D., C.D.