Retinol, a type of vitamin A, has amazing anti-aging effects on the skin. When you put it on your face, it changes both the top and deeper layers of the skin. It helps key skin cells like keratinocytes, fibroblasts, and endothelial cells. Retinol makes the top layer of skin thicker by activating stem cells and helping keratinocytes grow.  It also improves the deeper layer by activating fibroblasts and helping new blood vessels form. This process boosts collagen in older skin, which leads to better skin texture, fewer dark spots, and a younger look. The combined effects of these changes explain why retinol is so good for anti-aging.