Two Main Forms Of K2
MK4 is synthetic and should not be used.
MK7 is natural, long chain form, from fermented food, and is the right choice along with vitamin D3 for providing heart health by removing excess calcium from the arteries and putting it in the teeth and bones where it belongs.
A daily dose of 200mcg of MK7 from natto is a good start.
Let Food Be Your Medicine And Medicine Be Your Food.(Hippocrates)