FLEX PAK is an advanced formula that contains collagen hydrolysate, L-proline, MSM, glucosamine sulphate, chondroitin sulphate, sodium hyaluronate, vitamins C and B6, calcium, and magnesium. Vitamin C contributes to normal collagen formation for the normal function of bones, cartilage, and blood vessels. Magnesium and calcium contribute to normal muscle function. Recommended...