Yes. Although calcium is generally safe when taken as directed, but there are some risks in taking it as a supplement. It may not be safe to use calcium if you have certain medical conditions like allergies, diarrhea, gastrointestinal problems, heart disease, hypercalcemia (high calcium levels in blood), hypercalciuria (high calcium levels in urine), too much parathyroid hormone or too little, high or low phosphate levels in the blood, kidney disease, kidney stones, or sarcoidosis. Discuss taking calcium with your doctor before using it if you have any of these conditions.
Though calcium is often recommended for pregnant and breastfeeding women, they should talk to their doctors or pharmacist about proper dosing before using it, as large doses may cause harm to the mother or child. Calcium can interact with several medications which can decrease the effectiveness of the medication, cause dangerously low or high calcium levels, or even cause serious health complications. Talk to your doctor about all medications or other supplements you're taking.Calcium may cause side effects such as constipation, belching, and gas. If you experience any of the following side effects, contact your doctor, as they may indicate a serious problem: allergic reaction symptoms, confusion, excessive drowsiness, frequent urination, heart rate changes, kidney stones, muscle weakness, nausea, and vomiting. Taking too much calcium can lead to a harmful condition called calcium toxicity. Discussing the risks of calcium with your doctor or pharmacist may help you decide if the supplement is right for you.