Google "vitamin d3 and blood clotting nih"
The "nih" on the end tells Google to look first in the NIH listings (this filters out a lot of garbage when searching for information on health issues).
One of several pages returned was:
The relationship between vitamin D status and idiopathic lower-extremity deep vein thrombosis "Conclusion
Low levels of 25(OH)D are associated with idiopathic lower-extremity DVT. Further investigation is needed to establish determinants and probable causative role of 25(OH)D."
From:Mrs.Z to SkyDancer
You need K2 to help D3 absorption, not K1. K1 is the supplement associated with blood clotting.
That is what I take: the K2+D3 - I have D3 alone but not taking it right now.