Other name(s):

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

Unsubstantiated claims

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

Isoleucine may play a critical role in hemoglobin (the oxygen-carrying pigment inside red blood cells) production. It may regulate blood sugar level, increase energy and endurance, and help speed healing of injured muscle tissue. Use of isoleucine has also been credited for increases in muscle development and lean body mass. 

Recommended intake

Amino acids (AAs), such as isoleucine, are available as individual AAs or in proprietary AA combinations, as well as part of multi-vitamin formulas, proteins, and food supplements. The forms include tablets, fluids, and powders. However, adequate protein in the diet should provide a sufficient source of all amino acids.

There are no conditions that increase the nutritional requirements for isoleucine.

Side effects, toxicity, and interactions

The use of a single amino acid supplement may lead to a negative nitrogen balance, decreasing metabolic efficiency and increasing the workload of the kidneys. In children, taking single amino acid supplements may also harmfully affect growth parameters.

Isoleucine supplements should be taken together with leucine and valine.

Always avoid taking individual amino acids in high dosage for prolonged periods.

Women who are pregnant or breastfeeding should not use isoleucine supplements.

Individuals with maple syrup urine disease (MSUD), a rare inherited disorder, should not use isoleucine or the other branched-chain amino acids (leucine or valine).

Additional information

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