You could say we’re obsessed with all things skincare—from the latest scientific breakthroughs to the best new treatments—but sometimes the most effective ingredients aren’t new at all. To wit: Cleopatra soaked in milk baths thousands of years ago to make her skin more beautiful. While the Egyptian leader didn’t know it at the time, alpha hydroxy acid was delivering the exfoliating, anti-aging, and brightening benefits.
Think of alpha hydroxy acid (or AHA) as the blue jeans of the skincare industry: no matter your age, concern, skin type, or tone, they’ll work for you. What exactly are they and what do they do? Click through our slideshow for everything you need to know.