Doctor insights on:
Calcium supplements: Young males may not need calcium supplements at all. Ask your doctor to do a bone density exam, and check your blood levels to determine need, as excess can lead to renal, stones and other problems. Supplements include oyster shell with vit D, Ca citrate, or just dairy products like milk, cheese, yogurt, and even Ice cream. First determine the need for replacement.
Yes you can: Get a falsely high level of calcium due to different conditions, or simple lab error. If you repeat the test and it still shows high serum calcium, then you need to get more tests to see why. Dehydration, low magnesium, low albumin, and muscle conditions like rhabdomyolysis can cause higher calcium levels in the blood. Of course there are serious diseases like Paget's and cancer too.
Essential: Calcium is a mineral that plays an important role in bone health. Calcium is also needed in proper functioning of the heart (to keep it beating), muscles (to keep them bending), and nerves (to keep them firing). Some people who suffer from kidney failure benefit from taking calcium to maintain strong bones. The amount of calcium supplements required in an individual depends on age and gender.
1200 mg daily: A good rule of thumb for adults is 1200 mg daily plus what you take in with meals. Calcium supplements usually come in 600 mg tablets and you take one twice daily. They may contain vitamin d in the amount of 400 units each as well, though you can get them without the vit. D. Pending your age, risks, medical conditions etc, you should be safe. If quesitons, ask your pcp about you in particular.
1000mg mainly diet: For your age (assuming this is for you) the NIH recommends that you should take 1000mg of calcium. But, most women in the US obtain enough calcium from their diet. Bone loss generally occurs around 30. So, unless you are at high risk of osteoporosis you probably do not need a Calcium supplement, those found in multi-vitamins should be sufficient.