From a 2017 meta-analysis on Vitamin K1 and K2:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5494092/
"Some of the recent review articles suggest that there is insufficient information in the literature to recommend the use of vitamin K1 supplements to prevent bone loss, fractures, and osteoarthritis in humans [52]. Researches looking at these effects when supplementing vitamin K1 on bone density and vascular calcification are generally negative or show no difference.
Studies using vitamin K2 demonstrate improvement in bone quality rather than bone density, while significantly reducing fractures and preventing vascular calcification. For this reason, the literature is sometimes confusing and care must be taken to clearly look at the differences in actions of vitamins K1 and K2. There is a need for more research to be done on vitamin K2 in regard to its effect on arthritis, cognition, diabetes, renal calculi, and cancer.
Vitamin K2 in the form of MK-7 is rapidly becoming popular as a supplement and is available OTC usually with a dose of 100–120 μgm. It is important as physicians to be aware that MK-7 can interfere with anticoagulation therapy when used above 50 μgm/day [48]. On the other hand, the supplementation of some vitamin K at a steady level during anticoagulation therapy may result in a more stable INR that requires fewer adjustments. Using a small dose of vitamin K2 may benefit the patient by reducing the risk of osteoporosis, osteoarthritis, and vascular and tissue calcification. Well-controlled RCT studies are urgently needed in this area, especially given the well tolerated safety profile of vitamins K1 and K2.
Newer agents for anticoagulation such as dabigatran, rivaroxaban, and apixaban are not vitamin K-dependent. This would allow for the safer use of higher doses of vitamin K to prevent atherosclerosis, osteoporosis, and cognitive impairment, which may have the potential to reduce morbidity and mortality in this patient population [53].
The use of vitamin D and vitamin K2 together as an approach to osteoporosis treatment may significantly reduce morbidity and mortality. This approach may rival bisphosphonate treatment without the side effects associated with the use of this medication, along with reducing vascular calcification and its complications."