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L Leucine

L-Leucine (C6H13NO2) is an essential branched-chain amino acid (BCAA) that's broken down in fat structures. The other two essential BCAA's are L-Valine and L-Isoleucine.

L-Leucine cannot be made by the body, and must be acquired through food or dietary supplements. It can be found in nuts, brown rice and whole wheat bread products.

Deficiency of leucine is rare. Insulin deficiency is known to result in poor utilization of leucine. A deficiency of leucine can cause a biochemical malfunction producing hypoglycemia in infants. Hypoglycemia symptoms may include dizziness, fatigue, headaches, irritability etc. Leucine comprises about eight percent of the total amino acid count in your body's protein structures; it is the fourth most concentrated amino acid in skeletal muscle tissue. As one of the three BCAA's, L-Leucine is essential to your basic health. It has athletic applications.

L-Leucine has many beneficial effects on sports performance. It helps preserve lean muscle tissue, it supplies the body with energy when under stress (i.e. when engaging in athletic activity), it preserves muscle glycogen (glucose stored in muscle tissue used to power muscular contraction), it maintains nitrogen balance, and it enhances thinking abilities that can decline as physical activity becomes more intense.

The effects of L-Leucine in the diet are profound. As the strongest of the BCAA's, L-Leucine is what's known as a "limiting nutrient" - meaning that you must have enough L-Leucine in proportion to other amino acids in order for your body to make use of what you eat. If you suffer from an L-Leucine deficiency, your body will not be able to make use of the protein that you give it - no matter how much protein you consume. And, unless you have enough L-Leucine, the money you spend on quality food and dietary supplements will be wasted. To make the most of what you eat, you need two parts L-Leucine and two parts L-Valine for every one part of L-Isoleucine. You'll fail to get optimal results if you fall short of meeting this exact ratio.

What is L-Leucine ?
L-Leucine is one of the 20 most common amino acids on earth, and coded for by DNA. Its chemical composition is identical to that of Isoleucine, but its atoms are arranged differently resulting in different properties. Leucine is obtained by the hydrolysis of protein by pancreatic enzymes during digestion and necessary for optimal growth in infants and children and for the maintenance of nitrogen balance in adults. Leucine is a member of the branched-chain amino acid family, along with valine and Isoleucine. The branched-chain amino acids (BCAAs) are found in proteins of all life forms. The three branched-chain amino acids constitute approximately 70 percent of the amino acids in the body proteins. Leucine is an essential amino acid, meaning it cannot be synthesized by the body and must be obtained through food.

Where it is found
Leucine is found primarily in high quality protein foods such as beans, brewer's yeast, brown rice bran, caseinate, corn, dairy products, eggs, fish, hemp seed, lactalbumin, legumes, meat, nuts, pumpkin seeds, seafood, seeds, soy, squash seeds, whey, whole grains.

Benefits / uses
Leucine is necessary for the optimal growth of infants and for the nitrogen balance in adults. It appears to have no particular therapeutic role, but it is vital in supporting functions. Leucine lowers elevated blood sugar levels and is necessary in promoting the healing of bones, skin, and muscle tissue. Leucine is used as a source for the synthesis of blood sugar in the liver during starvation, stress, and infection to aid in healing. Leucine is a direct-acting nutrient signal that regulates protein synthesis in adipose tissue. Leucine works with valine and Isoleucine to protect and fuel the muscles. Leucine is believed to help a person maintain muscle mass, which is essential for long-term weight management because muscle helps the body burn more calories. Supplements and protein powders that contain leucine are used extensively by bodybuilders and other athletes to promote muscle recovery. It also works to increase endurance and enhance energy. Leucine is an important amino acid for the production of hemoglobin. It maintains blood sugar levels and increases growth hormone (HGH) production. Leucine is found in both animal and vegetable products. The branched chain amino acids (BCAA), valine and Leucine, play an important role in stress, energy and muscle metabolism. BCAAs may be helpful in a minority of patients with hepatic encephalopathy.

Young adults need about 31 mg of this amino acid per day per kilogram (14 mg per lb) of body weight. Therapeutic use of leucine occurs at doses between 500 and 1,000 mg per day.

Possible Side effects / Precautions / Possible Interactions:
Leucine is considered safe for general use. People with depression, liver or kidney disease should avoid taking large amounts of leucine due to the changes of blood levels. Leucine may interfere with L-dopa, however, a medication used to control the symptoms of Parkinson's disease and should be used only under medical supervision in these patients.

Research studies / References

arw Dawson, R.M.C., et al., Data for Biochemical Research, Oxford, Clarendon Press, 1959.

arw IUPAC-IUBMB Joint Commission on Biochemical Nomenclature. "Nomenclature and Symbolism for Amino Acids and Peptides". Recommendations on Organic & Biochemical Nomenclature, Symbols & Terminology etc. 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 J. Rosenthal, et al. Department of Medicine, University of Toronto, Toronto, Canada. "Metabolic fate of leucine: A significant sterol precursor in adipose tissue and muscle". American Journal of Physiology Vol. 226, No. 2, p. 411-418. Retrieved 2008-03-25.

arw Etzel MR (2004). "Manufacture and use of dairy protein fractions". The Journal of Nutrition 134 (4): 996S–1002S. PMID 15051860.

arw L. Combaret, et al. Human Nutrition Research Centre of Clermont-Ferrand. "A leucine-supplemented diet restores the defective postprandial inhibition of proteasome-dependent proteolysis in aged rat skeletal muscle". Journal of Physiology Volume 569, issue 2, p. 489-499. Retrieved 2008-03-25.


National Nutrient Database for Standard Reference. U.S. Department of Agriculture. Retrieved 2009-09-16.

arw Meierhenrich: Amino acids and the asymmetry of life, Springer-Verlag, 2008, ISBN 978-3-540-76885-2