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
Example Sentences
Recent Examples on the Web For Dullness: Perk up your complexion and smooth uneven texture with Dr. Dennis Gross's power blend of vitamin C, lactic acid and niacinamide. 
Jackie Fields, Peoplemag, 30 Aug. 2022 This creamy clay mask is infused with volcanic clusters from the island and lactic acid. Kiana Murden, Vogue, 23 Aug. 2022 What makes the Vitamin C Lactic 15% Vitamin C Firm & Bright Serum unique is the combination of vitamin C and lactic acid. Noel Cody, Essence, 22 Aug. 2022 This Briogeo shampoo is packed with lactic acid to moisturize the scalp, while pulling out any buildup from products and oils. ELLE, 11 June 2022 In addition to the new cosmetics, Keys Soulcare already offers a cleanser made with manuka honey, a powder exfoliator with lactic acid and an illuminating priming serum with niacinamide. Robyn Merrett, PEOPLE.com, 6 May 2022 For marinating and baking, one strategy is simply to use milk with the addition of an acid to fulfill the missing lactic acid’s role as a tenderizer and/or activator of leavening agents. Charlyne Mattox, Country Living, 12 Aug. 2022 There’s the burn of lactic acid and the roar of the crowd. Outside Online, 28 July 2022 The lactic acid produced by the probiotics in the food can break down dead skin cells, gently exfoliating the skin and brightening its tone. New York Times, 16 June 2022 See More
Jackie Fields, Peoplemag, 30 Aug. 2022 This creamy clay mask is infused with volcanic clusters from the island and lactic acid. Kiana Murden, Vogue, 23 Aug. 2022 What makes the Vitamin C Lactic 15% Vitamin C Firm & Bright Serum unique is the combination of vitamin C and lactic acid. Noel Cody, Essence, 22 Aug. 2022 This Briogeo shampoo is packed with lactic acid to moisturize the scalp, while pulling out any buildup from products and oils. ELLE, 11 June 2022 In addition to the new cosmetics, Keys Soulcare already offers a cleanser made with manuka honey, a powder exfoliator with lactic acid and an illuminating priming serum with niacinamide. Robyn Merrett, PEOPLE.com, 6 May 2022 For marinating and baking, one strategy is simply to use milk with the addition of an acid to fulfill the missing lactic acid’s role as a tenderizer and/or activator of leavening agents. Charlyne Mattox, Country Living, 12 Aug. 2022 There’s the burn of lactic acid and the roar of the crowd. Outside Online, 28 July 2022 The lactic acid produced by the probiotics in the food can break down dead skin cells, gently exfoliating the skin and brightening its tone. New York Times, 16 June 2022 See More Word History
First Known Use
1790, in the meaning defined above
Medical Definition
lactic acid
noun
: a hygroscopic organic acid C3H6O3 that is known in three optically isomeric forms:
a
or D-lactic acid
ˈdē- 
: 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
ˈel-
: the levorotatory form obtained by biological fermentation of sucrose c
or DL-lactic acid
ˈdē-ˈel-
: 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