L-Isoleucine is one of three branched chain amino acids (BCAAs), the other two being L-leucine and L-valine. These BCAAs are found in proteins of all forms of life. They can be obtained in the diet through animal and vegetable sources. L-Isoleucine is important in hemoglobin synthesis and in the regulation of blood sugar and energy levels. It also increases endurance.

L-Isoleucine is an isomer of Leucine. L-Isoleucine is metabolized in muscle tissue. Rich sources of L-isoleucine include cashews, almonds, and soy protein. L-Isoleucine is popular among athletes. It is typically taken or used with the other two BCAAs, L- Leucine and L-valine.

L-Isoleucine is an essential amino acid primarily used to boost energy, improve physical endurance and speed up recovery time after strenuous exercise.
L-Isoleucine is the fourth most abundant amino acid in human skeletal muscles, comprising about 12% of all proteins in the human body. As an essential amino acid, L-isoleucine cannot be manufactured in the body and must be consumed through dietary sources, or supplementation, to maintain proper health. Good sources of isoleucine include high-protein foods such as nuts, almonds, seeds, meat, cashews, eggs, fish, chicken, liver, lentils, peas, soy protein, brown rice and whole wheat bread products.

Isoleucine is highly concentrated in muscle tissue. For this reason those who exercise often and those on low-protein diets should consider supplementation. This dietary supplement is particularly important to serious athletes like bodybuilders and weightlifters.

L-Isoleucine is typically taken by performance athletes working to reduce fat and maximize muscle mass. Blood levels of L-isoleucine will fall significantly after strenuous exercise and will stay low until complete recovery. Supplementation with isoleucine one hour before strenuous workouts can reduce the recovery time by increasing muscle protein synthesis and counteract catabolic (breakdown) processes.

Isoleucine is used for energy within the muscle tissue. A deficiency of isoleucine manifests symptoms similar to those seen in hypoglycemic patients, and may include headaches, dizziness, fatigue, depression, confusion, and irritability.

Isoleucine in one of the three branched-chain amino acids (BCAA) and should always be taken in conjunction with the other two: leucine and valine. For every milligram of isoleucine, take two milligrams of Leucine and one milligram of valine.

All three BCAAs are essential in helping encourage muscle recovery after exercise. Isoleucine in particular keeps energy levels stable by helping to regulate blood sugar.

BCAAs promote protein synthesis in muscle. They serve as important fuel sources for skeletal muscle during periods of metabolic stress. BCAAs are needed for the maintenance of muscle tissue and appear to preserve muscle stores of glycogen. BCAAs also help prevent muscle protein breakdown during exercise.Where it is found
Dietary sources of L-Isoleucine include eggs, cashews, almonds, fish, chicken, soybeans, chickpeas, lentils, liver, milk, cottage cheese and cereal grains. Because no one ingredient works totally on its own, and is enhanced by other ingredients combined with it, we recommend you include L-glutamine as part of a complete homeopathic hgh (human growth hormone) product.

Benefits / uses
Isoleucine helps maintain healthy and optimal levels of blood sugar and energy. As an amino acid, one of the building blocks of protein, it is needed for the formation of hemoglobin.

This amino acid plays a key role in muscle recovery after exercise and in metabolism for producing energy. Isoleucine is broken down within muscle tissue to provide energy.

It is also essential for the manufacture and synthesis of body proteins and is directly involved in blood clot formation.
Isoleucine is required for nitrogen balance in adults and for the healthy, normal growth of infants.
The suggested serving size for L-isoleucine is 1000 to 2000 milligrams taken orally three times daily. Some athletes use larger amounts based on individual preference or the recommendation of a professional trainer.

You can see the full bulk density/volumetric conversion chart for L-Isoleucine here. A rounded 1/4 teaspoon will provide about 1000 mg; a rounded 1/2 teaspoon will give about 2000 mg.

If you take 1000 mg of Isoleucine, simultaneously take 1000 mg valine and 2000mg leucine for your total BCAA.

Possible Side effects / Precautions / Possible Interactions:
Isoleucine, as one of three branched-chain-amino-acids (BCAAs), should always be taken in balance with the other two. For every milligram of isoleucine, take two milligrams of leucine and one milligram of valine.

Deficiency of isoleucine may be present in people whose diet lacks sufficient protein intake. Symptoms may include headaches, dizziness, fatigue, depression, confusion as well as irritability. Symptoms of deficiency may resemble those of hypoglycemia.

Those with kidney or liver disease should not consume amino acids without medical advice. People with impaired liver or kidney function should not take isoleucine without first consulting a physician, as large quantities of amino acids may aggravate these conditions.

Research studies / References
arw IUPAC-IUBMB Joint Commission on Biochemical Nomenclature. "Nomenclature and Symbolism for Amino Acids and Peptides". Recommendations on Organic & Biochemical Nomenclature, Symbols & Terminology etc.

arw Retrieved 2007-05-17.

arw Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. ISBN 1-57259-153-6.

arw [1], List is in order of highest to lowest of per 200 Calorie serving of the food, not volume or weight.

arw "dl-Isoleucine", Org. Synth., 1955,

arw; Coll. Vol. 3: 495

arw Bouveault and Locquin, Compt. rend., 141, 115 (1905).