MK4 is the natural form we get from pastured animal food and all other forms of K get converted to this in the body as it is the preferred form. you cant imitate it in a pill and is why it it not recommended as a supplement. MK7 is from bacterial ferments and is easy to make a supplement. The thinking that an increased half life of MK7 over MK4 is an advantage is seriously flawed thinking. half life increase does not dictate the superiority of a nutrient compared to another. calcitriol, the active form of Vitamin D has a miniscule blood level half life compared to its inactive form in which they both have very different functions. The MK7 and MK4 have many different effects in the body so to say one is superior because of half life is just part of a sales pitch to bias an MK7 supplement. MK-4 has effects on gene expression in bone tissue that MK-7 doesn't have.
Mammals can synthesize K2 MK-4 from K1. greater than 90% of our tissue saturation is from MK4 not MK7. why would you want to offset this ratio with mega dosing MK7. www.ncbi.nlm.nih.gov/.../18083713 Here is a study that shows MK7 supplements are converted to MK4 and results in increased levels of vital tissues skin, kidney, heart and brain. This sows the metabolic preference of MK4 over MK7 clearly showing that natural animal dietary sources is what we should be opting for. find info at bottom of study. www.ncbi.nlm.nih.gov/.../PMC3195265