Which of the following stimulates cell turnover?

Alpha hydroxy acids (AHA), such as glycolic acid and lactic acid, are known to effectively stimulate cell turnover. They work by exfoliating the upper layers of the skin, promoting the shedding of dead skin cells and encouraging the growth of new cells. This process helps improve skin texture, tone, and overall appearance. AHAs are water-soluble and exude their effects primarily on the surface of the skin, making them particularly beneficial for individuals looking to enhance skin radiance and reduce the appearance of fine lines and other signs of aging.

While Vitamin C, salicylic acid, and retinoids also play significant roles in skincare and may contribute to different aspects of skin health and appearance, they do not serve as primary agents for stimulating cell turnover in the same direct manner as AHAs. Vitamin C is primarily an antioxidant that promotes brightness and reduces pigmentation, salicylic acid is effective at treating acne due to its ability to penetrate pores and reduce oil, and retinoids encourage deeper skin cell renewal and collagen production but operate in a different biochemical pathway compared to AHAs. Thus, AHAs stand out specifically for their role in promoting the turnover of surface skin cells.