Is vitamin k supplement a blood thinner or a blood thickener? should i take vitamin k2 supplement while i am taking vitamin d 2000iu supplement?

Vitamin K: helps blood to clot. You shouldn't need vitamin K supplementation except if your physician prescribes it.

Neither: Hi. Vitamin K is required for gamma-carboxylation of glutamic acid in the clotting factors. Too little vit. K makes you unable to make the clotting factors. This is basically how warfarin works. But clotting factors are tightly regulated, and taking a vit. K supplement if you're not deficient will have no effect on clotting.