Which type of calcium supplement is best for you?

None: Given recent studies showing increased risk of calcification of blood vessels due to oral calcium supplements, i recommend against them. Get calcium from foods which are not believed to contribute to calcification such as tofu, salmon, and low-fat no sugar added yogurt.

Calcium: Depending on your diet, you may or may not need supplemental calcium. You can get a lot from leafy greens, tofu, yogurt, cheese, milk, sardines, salmon, etc. http://tinyurl.com/d8bvfbn around 900-1200 milligrams of calcium per day are enough. If you aren't getting this much in your food, calcium citrate is better absorbed than calcium carbonate. Use a product that also has vit d and vit k2.

Citrate vs carbonate: Calcium carbonate is less expensive and it can be also used for acidic heart burn. Calcium citrate adsorbs faster and easier, it doesn't cause constipation as likely as carbonate does.