PURE COLLAGEN works because it is PURE natural COLLAGEN – the essential building blocks that your body needs to be its best. Second to only water, PURE COLLAGEN is the most important substance in our bodies. It’s the primary nutrient in your hair, skin and nails. It also strengthens and rebuilds your tendons, joints, bones, and skeletal muscle tissue. Using PURE COLLAGEN produces real and lasting results because it supports and strengthens these collagen structures. These structures use collagen to increase your energy, support a healthy metabolism, keep body fat levels low, nourish, strengthen and produce radiant skin, healthy hair and strong nails, support strong healthy joints and finally help you sleep longer and better. 16 fluid ounces.