What I bought for my family was the collagen of Tomson Bianjian, which contains high calcium content.
It is mainly the repository of bone collagen such as calcium, which can effectively promote calcium deposition, prevent calcium loss and improve the absorption rate of calcium by bones.
Because chondroitin locks bone moisture like a "liquid magnet", collagen directly reaches cartilage tissue, maintains bone toughness, accelerates cartilage repair, and eliminates joint pain, swelling and stiffness.
My dad had joint pain before, and then he ate the high-calcium collagen I bought him. Soon, his joints stopped hurting and he walked easily.