Washington Master Esthetics Practice Exam

Which AHA is known for having a small molecular size and weight?

1. Glycolic acid

2. Citric acid

3. Lactic acid

4. Malic acid

The correct answer is: Lactic acid

Glycolic acid is the AHA known for its small molecular size and weight, which allows it to penetrate the skin effectively. This characteristic enables glycolic acid to exfoliate the outermost layer of dead skin cells, promoting cell turnover, improving skin texture, and enhancing the overall appearance of the skin. Glycolic acid's smaller size is significant because it can reach deeper into the skin than other AHAs, making it more effective for various skin concerns, including signs of aging, hyperpigmentation, and acne. Due to its potency, it's commonly used in professional peels and various skincare products designed for exfoliation and rejuvenation. While lactic acid, citric acid, and malic acid are also effective AHAs, they have larger molecular sizes, which means they are generally less penetrative compared to glycolic acid. This difference influences their effectiveness and the strength of exfoliation they provide. Each AHA has its unique properties and benefits, but glycolic acid stands out for its effectiveness due to its small molecular structure.