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 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 This helps balance out the formula’s lactic acid, an exfoliator that can help reduce the appearance of pores and fine lines. Macaela MacKenzie, Glamour, 17 Feb. 2024 Key ingredients: 10% glycolic and lactic acids, pumice buffing beads, vitamin E | Base: Beads | Size: 8 oz. Alyssa Brascia, Peoplemag, 16 Feb. 2024 Serving as the brand’s first makeup product, this tint is enriched with a conditioning blend of shea butter, peptides, and lactic acid to keep lips soft and smooth while enveloping them in a wash of sheer-to-buildable glossy pigments. Alexis Bennett Parker, Vogue, 1 Dec. 2023 So, look for an OTC product containing alpha-hydroxy acids, like glycolic acid or lactic acid. Angela Palmer, Verywell Health, 17 Jan. 2024 It’s made with probiotic extracts to help with smoothness, ceramides to help retain moisture, and lactic acid to help with texture. Taylor Jean Stephan, Peoplemag, 11 Dec. 2023 More natural cleansers tend to use gentler ingredients like essential oils and lactic acid in order to achieve a similar result. Kaitlyn McInnis, Better Homes & Gardens, 3 Jan. 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

Time Traveler
The first known use of lactic acid was in 1790

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 19 Mar. 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

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