I don’t take anything without checking with my doctors as I’m on a lot of prescription meds. I had hypercalcaemia and hyperparathyroidism due to a tumour on a parathyroid gland, causing an overproduction of parathyroid hormone. This causes calcium to be leached from the bones, which in turn raises blood calcium, causes osteoporosis and kidney damage. I don’t pretend to understand how it all works, but people with HPT are often deficient in Vitamin D. The offending gland, plus another found during surgery have now been removed and I have yearly blood tests to keep an eye on my levels, including B12, potassium and sodium. I’m deficient in Vitamin D3 so take a daily capsule on the advice of my endocrinologist. I think the best thing for you to do is ask for a blood test including the above, then you’ll know if you’re deficient. There are many different strengths of D3 available over the counter so advice is needed to get the right one,