What is collagen? Your body's connective tissues produce collagen, a protein that promotes skin elasticity and firmness. Unfortunately, the older you grow, the less of it your body produces — that's when wrinkles, fine lines, and loose skin start to appear. To counteract aging signs and rejuvenate the skin, thousands of women — young and old — supplement their diet with collagen powder, which was first used in Japan, the world's cradle of skincare. After captivating the attention of celebrities and beauty editors for its effective beautifying properties, collagen supplements were quickly introduced to the western world. Collagen powders and pills are now available everywhere, though not all are created equal. With benefits ranging from tighter skin, stronger nails, faster muscle recovery and greater joint fortification, here are the most effective collagen supplements on the market.