Collagen is a protein found in connective tissues of the body. It is significant in making certain parts of the body such as nails strong and is also an important factor in joint health. Collagen supplements come in various forms. One of the most common is called Gelatin.
Calcium supplements come in several different forms, including calcium carbonate and calcium citrate. Calcium citrate is the easiest for your body to absorb and digest, making it less likely to cause adverse side effects like gas. However, calcium citrate only contains 21 percent elemental calcium, while calcium carbonate contains 40 percent. Elemental calcium is the actual amount of calcium present in a supplement.
Many natural calcium carbonate preparations such as oyster shells or bone meal contain some lead. The low lead levels in calcium supplements are unlikely to be a health risk because calcium blocks lead absorption. Calcium citrate is well absorbed in the fasting state. Calcium doses above 500 mg are not absorbed as well as smaller doses, so large doses of supplements should be taken in divided doses (eg, in the morning and evening).