Other name(s):

a-amino-b-methyl-n-valeric acid

Unsubstantiated claims

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

Isoleucine is an essential amino acid. Isoleucine is the oxygen-carrying pigment inside of red blood cells and helps to make hemoglobin. It is also helpful in controlling blood sugar, boosting energy, and improving endurance. Isoleucine is known to help speed healing of injured muscle and support muscle development and lean body mass. 

Recommended intake

Amino acids (AAs) can be taken as single AAs or in AA combinations. They also come as part of multivitamins, proteins, and food supplements. The forms include tablets, fluids, and powders.

If you eat enough protein in your diet, you will get all of the isoleucine your body needs.

There are no conditions that increase how much isoleucine 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 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 single amino acids for long periods of time.

These people should not take isoleucine:

  • People who are taking leucine and valine

  • Women who are pregnant or breastfeeding

  • People with maple syrup urine disease or cystinuria

Online Medical Reviewer: Amy Finke RN BSN
Online Medical Reviewer: Bianca Garilli MD
Online Medical Reviewer: Jessica Gotwals RN BSN MPH
Date Last Reviewed: 7/1/2023