Which of the following acids is derived from milk?

Lactic acid is indeed derived from milk, specifically through the fermentation of lactose, which is the sugar found in milk. This organic acid plays a significant role in various skincare formulations, especially in exfoliants and moisturizers. Lactic acid is recognized for its ability to promote cell turnover, enhance skin hydration, and improve the texture of the skin by gently exfoliating.

The other acids listed have different sources: citric acid is primarily found in citrus fruits, tartaric acid is derived from grapes, and malic acid is typically found in apples. Understanding the origin of these acids is important in the context of their application in skincare, as it reflects their properties and benefits for treating various skin concerns.