Could you take vitamin d3 with out calcium & vitamin d3?

Yes.: If you are a normal young and healthy male with a reasonable diet you probably do not need to take either of these. So it would be reasonable to take one without the other.

Yes, probably wise: Virtually every american needs to take vit. D3 during fall & winter as we can't get any from the sun then (unless you live way south) & food can't provide enough. However, it's easy to get adequate calcium from a good diet (esp. Eating leafy greens). Recent research suggests calcium supps increase risk of atherosclerosis! i advise taking vit k to insure calcium you absorb enters bones/not arteries.