neutral, genetically coded
amino acid which is essential in human nutrition.
Symbol: leu l
Molecular formula: C6H13NO2
Linear Structure Formula:
Isoelectric point (pH): 5.98
CAS Registry Number:
Leucine is an essential amino
acid, which cannot be manufactured in the body and is part of the three
branched-chain-amino-acids. Supplements and protein powders that contain leucine
are used extensively by bodybuilders and other athletes to promote muscle
Among the most beneficial and
effective supplements in any sports nutrition program are the branched chain
amino acids which includes the essential amino acids leucine,
isoleucine, and valine.
Deficiency of this nutrient is rare,
since all protein foods contains it, but vegans and vegetarians without adequate
protein sources may suffer from a deficiency. Hypoglycemia symptoms may appear
if the diet is deficient and may include dizziness, fatigue, headaches,
Dosage: The daily
dosage of leucine is about 16 mg per kilogram of body weight per day - which
would translate to about 1120 mg for a 70 kg male.
The dosage listed is the Recommended Daily
Allowance (RDA), but be aware that this dosage is the minimum that you require
per day, to ward off serious deficiency of this particular nutrient. In the
therapeutic use of this nutrient, the dosage is usually increased considerably,
but the toxicity level must be kept in mind.
If you are taking a supplement of
leucine, keep it in balance with the other two branched-chain-amino-acids
isoleucine and valine in the formula of 2 mg of leucine and valine for each 1 mg
of isoleucine. Leucine is found in protein foods, as well as brown rice, beans,
nuts and whole wheat.
Leucine may benefit body
composition. Researchers from the University of
Illinois Urbana-Champaign noted in a review that part of the benefit of a higher
protein diet for weight loss may be due in part to increased intake of the
branched chain amino acid (BCAA), leucine.1 They noted
leucine and the BCAAs aid in regulating both muscle protein synthesis and
In a rat study conducted in Sao
Paulo, Brazil, rats recovering from protein malnutrition that received a
leucine-rich diet had better body weight recovery than control rats, including
collagen recovery.2 And a small study of five lean women compared to
five women with abdominal obesity found lower rates of leucine release in obese
women following a 22-hour fast, indicating preservation of body protein during
1. Layman DK, Baum JI. "Dietary
protein impact on glycemic control during weight loss." J Nutr. 134,
2. Ventrucci G et al. "Effects of a
leucine-rich diet on body composition during nutritional recovery in rats."
Nutrition. 20, 2:213-7, 2004.
3. Patterson BW et al. "Regional
muscle and adipose tissue amino acid metabolism in lean and obese women." Am
J Physiol Endocrinol Metab. 282, 4:E931-6, 2002.