Marine Collagen with Magnesium and Vitamin C in watermelon flavor — by Ana María Lajusticia. Collagen is the body’s most abundant protein and a fundamental component of cartilage, tendons, bones (about 90%), and skin (around 70%). Proteins help maintain normal bone health and support the preservation and growth of muscle mass. Magnesium helps reduce tiredness and fatigue, and supports normal protein synthesis and bone maintenance. Vitamin C enhances iron absorption and contributes to the normal formation of collagen for the proper function of blood vessels, bones, and cartilage. Watermelon flavor.