Hello there... Thanks for your question. Mk4 and mk7 are both forms of vitamin k2 derived from different sources. While mk4 is derived from animal sources like dairy products, mk7 is derived from bacterial fermentation. Mk4 would be the ideal form of vitamin k2 advised but the problem now a days is that dairy products are not as rich in these vitamins as they used to be earlier. Also mk4 form stays in the circulation for less time compared to mk7 making it necessary to take it again and again to keep the action if mk4 going. Mk7 in the other hand is more bioavailable and once a day dosing is enough. Mk4 forms these days are synthetic. I would suggest you go for the mk7 form. Both promote cardiovascular health and bone health. I hope I have answered your question. Best regards. Dr. Anil Kumar Jain.