Description Easily Digested - Quick Acting Dietary Supplement. Twinlab Calcium Citrate Caps are easier to swallow and assimilate. Calcium citrate is an easily absorbed, soluble and chelated form of calcium preferred by many health and nutritional experts. It is less likely to cause constipation -- a very real and uncomfortable problem with certain calcium supplements. Twinlab Calcium Citrate Caps Plus Magnesium go to work quickly in the stomach. Calcium and magnesium tablets, on the other hand, need binders to hold them together. Naturally, these binders may resist dissolving, so it is possible for a calcium plus magnesium tablet to pass through the digestive tract without being completely absorbed.