Isoleucine is an essential branched-chain amino acid (BCAA). A building block of protein (as are all amino acids), isoleucine plays a vital role in protein synthesis, muscle building, and preventing muscle loss.
Isoleucine is found in most protein-rich foods, particularly meats, fish, cheese, and most seeds and nuts.
Popup: Foods highest in Isoleucine
Isoleucine, like all BCAA’s, is used by athletes whose muscles are excessively stressed by overtraining to promote healing of injured tissues, speed recovery, protect against muscle-tissue breakdown, and possibly increase lean mass.
Deficiency produces symptoms similar to hypoglycemia
Research indicates that Isoleucine may be useful in the treatment of:
Isoleucine is an essential (meaning the body cannot make it) amino acid that, along with valine and leucine, is one of the branched-chain amino acids. These three amino acids account for one third of all the protein in muscle tissue, and this significant contribution makes them highly important for helping build muscle and increase energy in muscle cells. They are also converted to other amino acids when deficiencies arise.
The branched-chain amino acids are important for protein synthesis, muscle building, and preventing muscle loss. Quite simply, without branched-chain amino acids, your muscle cells won’t heal or grow.
Recent research has even shown that the three branch-chained amino acids together can reduce muscle wasting (at least slightly) even in people who are bed-ridden.
Found in proteins, isoleucine is needed for the formation of hemoglobin, which carries iron in the blood, and for the regulation of blood sugar, which is burned for energy in the muscles during exercise. In addition, isoleucine is used as fuel by muscle cells and may spare other amino acids from being burned. Researchers theorize that muscle wasting in the elderly is due partially to a deficiency in isoleucine.
While isoleucine is an important amino acid, it doesn’t quite rank up there with the other branched-chain amino acids. Nonetheless, it does have a prominent role in muscle metabolism.
Some athletes choose to get their isoleucine from a quality whey protein powder. Others supplement with between 200 and 2,000 mg per day.
The branched-chain amino acids (BCAA) are often supplemented together — 5 grams of leucine, 4 grams of valine, and 2 grams of isoleucine per day is common, although the amounts needed can vary depending on the person’s weight.
Isoleucine is supplemented on an empty stomach with the other branched-chain amino acids in two divided dosages — one a half hour before training and then another before sleep because of their potential to stimulate the release of growth hormone.
Valine, leucine, and isoleucine, the trio known as the “branched-chain amino acids,” support each others’ effects.
No known toxicity.