Calcium is an essential nutrient for healthy living as it helps strengthen our bones and teeth. It also helps maintain proper functioning of muscles, nerves, blood vessels and hormonal transmission. 
However, what most people don’t know is that too much calcium can do a lot of harm. When calcium levels in the blood exceed the normal, a condition called Hypercalcaemia is caused. The symptoms of Hypercalcaemia include constipation, fatigue, lethargy, bone pain, nausea, abnormal heart rhythms, peptic ulcers, kidney stones, arthritis, depression and confusion. Severe cases of hypercalcaemia can even cause a coma or cardiac arrest. 
Another surprising effect of excessive consumption of calcium is the premature deterioration of the bones or osteoporosis. Bones contain cells called osteoblast cells (which create bone matrix) and osteoclast cells (which remove excess calcium from the bone matrix). Osteoblasts thus serve as a foundation for calcium to “mineralise” and form solid bone while osteoclasts eliminate and prevent calcium overload in the bones. Excess of calcium creates an imbalance between osteoblast and osteoclast functions. Osteoblasts simply cannot cope with the amount of calcium being taken out of the system and end up dying. As a result, the bone matrix finds itself losing a great deal of calcium despite an excessive amount of calcium being introduced into the body. 
1. Hyperparathyroidism: Hyperparathyroidism is one of the most common causes of excessive calcium absorption in the body.
This condition occurs when the parathyroid glands produce too much
parathyroid hormone (PTH). This hormone is responsible for a wide range of functions, including the release of calcium from the bone. Too much of PTH, causes the bones to uncontrollably release calcium, thereby causing and contributing to hypercalcaemia and osteoporosis.
2. Excessive supplementation: Sometimes people end up with too much calcium in their system because they consume too much calcium—through food or through thoughtless supplementation. Excessive consumption of dairy products like milk and cheese, coupled with excessive and reckless self-medication with antacids and calcium supplements can introduce too much calcium into your body.
The way we use magnesium is a perfect example of the way nature establishes balance in our bodies. Magnesium prevents calcium from being amassed in places it shouldn’t be massing in. If too much calcium settles in the soft tissues of the joints, then it will cause arthritis. If calcium settles in the lungs, then it will cause respiratory problems. If calcium settles in the kidneys, then it will form kidney stones. If calcium settles in the heart, then it will cause cardiac arrest. And so on and so forth. Calcium and magnesium work in tandem when it comes to muscle and nerve functions. Calcium plays a role in stimulating the muscles and nerves of the body, while magnesium relaxes the same muscles and nerves. Magnesium also has protective features that balance out the negative effects of calcium overload on the heart. Magnesium is nature’s Calcium Channel Blocker. It blocks the entry of calcium into heart cells and vascular smooth muscle cells, reducing vascular resistance and naturally lowering blood pressure. An Italian study carried out in 1988 studied action of magnesium salts on the toxic effects of calcium overload. The study found that magnesium reduced the toxic manifestations of calcium overload and prevented cardiac standstill.
It is important to maintain the proper balance between magnesium and calcium. Too much or too little of either nutrient will yield adverse reactions. A 2:1 ratio of calcium (twice the amount of calcium) to magnesium is sufficient in most cases. However, a 1:1 ratio of Cal-Mag or even a reverse 2:1 ratio (magnesium being 2 and calcium 1) may be advised especially if your diet is high in calcium or if certain medications or medical conditions prevent your body from obtaining magnesium from your diet.
Magnesium supplements provide the magnesium the body needs in the most direct and effective manner possible. You can buy a magnesium-only supplement like Mag365 to balance your calcium intake. Another good idea would be to replace your current calcium supplements with a Cal-mag supplement like Mag365 plus Calcium. This is a superior Magnesium-Calcium formulation with magnesium and calcium in ratio of 3:2. It helps prevent a surplus of calcium robbing the body’s magnesium supply. It also includes potassium and vitamin D for better absorption of these key minerals.