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

According to Savchuk, the Prodigy Peel is a superficial yet medical-grade peel that blends resorcinol, lactic acid, salicylic acid, and citric acid to target mild to moderate aging, acne, and hyperpigmentation. —Larry Stansbury, Essence, 29 Apr. 2025

The lymphatic system, found within the body's connective tissue (fascia), acts as a drainage network for waste the veins can't handle—like bacteria, lactic acid, and toxins, according to Sorrel Pindar, a former osteopath based in the U.K., who spoke to Newsweek. —Nicholas Creel, MSNBC Newsweek, 20 Apr. 2025

Key Ingredients: Glycolic acid, lactic acid, salicylic acid, chickpea flour Size: 1.69 oz. —Emily Orofino, Vogue, 19 Apr. 2025

Chemical exfoliation involves using medications such as alpha hydroxy acids (such as glycolic and lactic acid) to dissolve dead skin cells.3 Exfoliate your skin about once or twice a week for optimal results. —Carrie Madormo, Rn, Mph, Verywell Health, 30 Apr. 2025

Word History

First Known Use

1790, in the meaning defined above

Rhymes for lactic acid

• antacid
• placid

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

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