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lactic acid
noun
: a hygroscopic organic acid C3H6O3 present normally especially in muscle tissue as a by-product of anaerobic glycolysis, produced in carbohydrate matter usually by bacterial fermentation, and used especially in food and medicine and in industry
Examples of lactic acid in a Sentence
Recent Examples on the Web
In rare cases, some people may have an allergic reaction to the drug, or be at risk for a dangerous buildup of lactic acid in the bloodstream.
—Stephen C. George, Discover Magazine, 30 Apr. 2024
Key ingredients: Glycolic acid, lactic acid, citric acid Especially good for: Maintenance masking
Pros: Gentle enough to use up to twice a week
Cons: Pricey
14/20
EltaMD UV Clear Broadspectrum Sunscreen SPF 46
No skin care routine is complete without face sunscreen.
—Macaela MacKenzie, Glamour, 15 Feb. 2024
This formula features a blend of potent chemical exfoliants, including glycolic acid, lactic acid, tartaric acid, citric acid, and salicylic acid, to target excess oil production, dull skin, and hyperpigmentation.
—Jessie Quinn, Peoplemag, 25 Mar. 2024
Those two new components—lactic acid and diacetyl—make buttermilk an MVP in waffles and pancakes.
—Karla Walsh, Better Homes & Gardens, 22 Mar. 2024
Youth to the People 10% AHA + Yerba Mate Smoothing Energy Body Scrub, which combines AHAs and olive seed powder, and Sunday Riley Charcoal Smoothie, which uses salicylic acid and lactic acid plus biodegradable wax are two standouts.
—Hannah Baxter, Allure, 5 Mar. 2024
Yogurt is made by combining heated milk and bacteria, which begins the fermentation process and converts the sugar in milk to lactic acid and allows the milk to thicken and become tart.
—Clare Mulroy, USA TODAY, 25 Feb. 2024
Other helpful ingredients include willow bark to manage excess oil, lactic acid to exfoliate, along with vitamins A, C, E, Coenzyme Q10, and antioxidants to nourish skin.
—Chaunie Brusie, Rn, Parents, 26 Feb. 2024
That culture then produces lactic acid, which causes the milk protein to thicken into a creamy, slightly tart mixture.
—Genevieve Ko, San Diego Union-Tribune, 21 Feb. 2024
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'lactic acid.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Word History
First Known Use
1790, in the meaning defined above
Dictionary Entries Near lactic acid
Cite this Entry
“Lactic acid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lactic%20acid. Accessed 23 May. 2024.
Kids Definition
lactic acid
noun
lac·tic acid
ˌlak-tik-
: an organic acid present especially in muscle tissue as a result of the breakdown of carbohydrates (as glycogen), is made from carbohydrates usually by fermentation by bacteria, and is used especially in food and medicine
Medical Definition
lactic acid
noun
: a hygroscopic organic acid C3H6O3 that is known in three optically isomeric forms:
a
or D-lactic acid
: the dextrorotatory form present normally in blood and muscle tissue as a product of the anaerobic metabolism of glucose and glycogen
b
or L-lactic acid
: the levorotatory form obtained by biological fermentation of sucrose
c
or DL-lactic acid
: the racemic form present in food products and made usually by bacterial fermentation (as of whey or raw sugar) but also synthetically, and used chiefly in foods and beverages, in medicine, in tanning and dyeing, and in making esters for use as solvents and plasticizers
More from Merriam-Webster on lactic acid
Nglish: Translation of lactic acid for Spanish Speakers
Britannica.com: Encyclopedia article about lactic acid
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