What is L-Leucine?
Leucine is one of nine essential amino acids in humans (provided by food), Leucine is important for protein synthesis and many metabolic functions. Leucine contributes to regulation of blood-sugar levels; growth and repair of muscle and bone tissue; growth hormone production; and wound healing. Leucine also prevents breakdown of muscle proteins after trauma or severe stress and may be beneficial for individuals with phenylketonuria. Leucine is available in many foods and deficiency is rare. (NCI04)
Benefits of L-Leucine
“BCAA, particularly leucine, stimulate protein synthesis, increase reutilization of amino acids in many organs and reduce protein breakdown. Furthermore, leucine can be an important source of calories, and is superior as fuel to the ubiquitous intravenous glucose (dextrose). Leucine also stimulates insulin release, which in turn stimulates protein synthesis and inhibits protein breakdown. These effects are particularly useful in athletic training. BCAA should also replace the use of steroids as commonly used by weightlifters. Huntington’s chorea and anorexic disorders both are characterized by low serum BCAA. These diseases, as well as forms of Parkinson’s, may respond to BCAA therapy. BCAA, and particularly leucine, are among the amino acids most essential for muscle health.”
“Leucine, isoleucine and valine, the branched-chain amino acids (BCAA), make up about one-third of muscle protein. Of these, leucine has been the most thoroughly investigated because its oxidation rate is higher than that of isoleucine or valine. Leucine also stimulates protein synthesis in muscle and is closely associated with the release of gluconeogenic precursors, such as alanine, from muscle.”
“Leucine supplementation potentiated aerobic exercise training (AET) effects on exercise tolerance, which might be related to its recognized impact on skeletal muscle.”
“Leucine may improve healing of skin and bones. It may increase muscle development and lean body mass. It may also increase production of human growth hormone (HGH). It may even help control blood sugar.”
“Using a single amino acid supplement may lead to negative nitrogen balance. This can decrease how efficient your metabolism is. 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 individual amino acids for long periods of time.”
“Very high doses of leucine may cause low blood sugar (hypoglycemia). It may also cause pellagra. Symptoms of this condition can include skin lesions, hair loss, and gastrointestinal problems.”
“Women who are pregnant or breastfeeding shouldn’t use leucine supplements. People who have maple syrup urine disease (MSUD), a rare inherited issue, shouldn’t take either. They also shouldn’t take the other branched-chain amino acids. These include isoleucine and valine.”
Leucine (abbreviated as Leu or L; encoded by the six codons UUA, UUG, CUU, CUC, CUA, and CUG) is an α-amino acid used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH+
3 form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO− form under biological conditions), and an isobutyl side chain, classifying it as a nonpolar (at physiological pH) amino acid. It is essential in humans—meaning the body cannot synthesize it and thus must obtain from the diet.
Leucine is used in the liver, adipose tissue, and muscle tissue. Adipose and muscle tissue use leucine in the formation of sterols. Combined leucine use in these two tissues is seven times greater than in the liver.