Your body is begging for collagen if you have the following: weak ligaments and tendons, joint pain, wrinkles or saggy skin, thin, dry, fragile hair, brittle, slow-growing nails, loss of muscle and the increased need for longer repair after exercise, and also bone loss because 90% of bone is made out of collagen. And the best source of collagen is not tender, lean meat. It's the skin on the chicken or fish. Bone broth, gelatin, pork skins, and even egg whites are loaded with collagen.