if you buy vitamins, go with d3 plus calcium. It'll assimilate better. The two pretty much ;go hand in hand with each other. The whole multi vitamin complexes are usually junk and unnecessary and synthetics are never better than natural. But for synthetics D3 = the good stuff.
what sort of calcium dose? How are you on calcium supplementation in general?
I supplement with 1000iu D3 a day if that makes any difference.
In general all vitamin supplementation is unnecessary. The exceptions being vitamin d and calcium. Usually 1g of calcium is suffice. It's unnecessary for most( assuming a sound diet), but it never killed anybody. The at risk crowd are those who are elderly and more so women are the ones who should take it. But another way to look at it is how much good is taking calcium if you already have osteoporosis? So maybe everybody starting at a young age should take it. So taking 1000 iu d3 plus 1 g calcium would be great.