There may be benefits that have not yet been proven through research.
Leucine is one of the 3 branched chain amino acids. These amino acids can be used
by skeletal muscle to give energy during exercise. Eating foods that have complete
protein gives enough of these amino acids. This includes foods such as meat, poultry,
fish, eggs, and milk. Results of studies have not been reliable in showing that taking
supplements of these amino acids improves exercise performance, or builds muscle mass,
or helps you recover from exercise. Leucine may help healing of skin and bones. It
may increase muscle growth and lean body mass. It may increase production of human
growth hormone (HGH). It may help control blood sugar.
Amino acids (AAs) are available as single AAs or in AA combinations. They also come
as part of multi-vitamins, proteins, and food supplements. The forms include tablets,
fluids, and powders.
By eating enough protein in your diet, you get all of the amino acids you need.
You should take leucine supplements with valine and isoleucine.
There are no conditions that increase how much leucine you need.
Side effects, toxicity, and interactions
Using a single amino acid supplement may lead to negative nitrogen balance. This can
lessen how well your metabolism works. It can make your kidneys work harder. In children,
single amino acid supplements may cause growth problems.
You should not take high doses of single 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 can include skin lesions, hair loss, and gastrointestinal
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.