AHA, or alpha hydroxy acid, is a skin care product ingredient made from fruit, milk or sugar cane. The makers of products with AHA promote its ability to reduce the signs of aging and to improve acne. Lactic (from milk), glycolic (from sugar cane) and citric acids (from oranges and lemons) are the most commonly used AHAs. AHAs have some side effects that make them inappropriate for many people. Does this Spark an idea?