: a white crystalline essential amino acid C6H13NO2 that is obtained by the hydrolysis of dietary protein (as of eggs, soy, or fish) and plays an important role in various physiological functions (as the regulation of insulin secretion and stimulation of protein synthesis in skeletal muscle)
Examples of leucine in a Sentence
Recent Examples on the Web
Challenging workouts and proper fueling will be your best muscle builders.
BCAAs
BCAAs contain three essential amino acids: leucine, isoleucine, and valine.
—
Donavyn Coffey, TIME, 1 Apr. 2024
This product, from Optimum Nutrition, delivers that plus a hearty 24 grams of protein per serving, including 3 grams of leucine.
—Jenny McCoy, Glamour, 2 Feb. 2024
Branched-chain amino acids (BCAAs) are three critical amino acids known as leucine, isoleucine, and valine.
—Amber Smith, Discover Magazine, 16 Nov. 2022
Some dietary supplements, such as resveratrol, especially when used in combination with an amino acid called leucine, also help with weight loss, mobility and insulin sensitivity in people and horses.
—Jane Manfredi, The Conversation, 25 July 2023
These include leucine, valine, isoleucine and a handful of other amino acids your body cannot naturally produce.
—Dallas News, 15 Feb. 2022
High-quality protein is any protein that contains all of the nine essential amino acids (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine) that our bodies don’t make on their own.
—USA TODAY, 2 July 2023
Some are even fortified with more leucine than most casein or whey powders on the market.
—Paul Kita, Men's Health, 5 Apr. 2023
These essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenyalinine, threonine, tryptophan and valine.
—Alyssa Jung, Good Housekeeping, 5 Oct. 2021
Donavyn Coffey, TIME, 1 Apr. 2024
This product, from Optimum Nutrition, delivers that plus a hearty 24 grams of protein per serving, including 3 grams of leucine.
—Jenny McCoy, Glamour, 2 Feb. 2024
Branched-chain amino acids (BCAAs) are three critical amino acids known as leucine, isoleucine, and valine.
—Amber Smith, Discover Magazine, 16 Nov. 2022
Some dietary supplements, such as resveratrol, especially when used in combination with an amino acid called leucine, also help with weight loss, mobility and insulin sensitivity in people and horses.
—Jane Manfredi, The Conversation, 25 July 2023
These include leucine, valine, isoleucine and a handful of other amino acids your body cannot naturally produce.
—Dallas News, 15 Feb. 2022
High-quality protein is any protein that contains all of the nine essential amino acids (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine) that our bodies don’t make on their own.
—USA TODAY, 2 July 2023
Some are even fortified with more leucine than most casein or whey powders on the market.
—Paul Kita, Men's Health, 5 Apr. 2023
These essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenyalinine, threonine, tryptophan and valine.
—Alyssa Jung, Good Housekeeping, 5 Oct. 2021
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'leucine.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Word History
Etymology
French, from leuc- leuk-
First Known Use
1826, in the meaning defined above
Dictionary Entries Near leucine
Cite this Entry
“Leucine.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/leucine. Accessed 19 Apr. 2024.
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Kids Definition
leucine
noun
leu·cine
ˈlü-ˌsēn 
: an amino acid that is very important in the nutrition of human beings
Medical Definition
leucine
noun
leu·cine
ˈlü-ˌsēn
: a white crystalline essential amino acid C6H13NO2 obtained by the hydrolysis of most dietary proteins
—abbreviation Leu
More from Merriam-Webster on leucine
Britannica.com: Encyclopedia article about leucine
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