<<Disclaimer: Verify this information before applying it to your situation.>> Dear Listmates - A listmate stated that vitamin K2 is Menaquinone. That is one form of vitamin K2, but not the MK-4 (or MK4) form of vitamin K2. I think that is the MK-7 (or MK7) form. The MK-4 form of vitamin K2 is Menatetrenone, and as reported in Archives of Internal Medicine, it was found to be more effective than the MK-7 form for bone density. I take the MK-4 form, Menatetrenone, and both Osteo-K and Relentless Improvement's K2 for bone density are the Menatetrenone (MK4) form. This is working for me, when nothing else did. There is a third form of vitamin K2, maybe MK-1. Not sure. But there are at least 3 forms of vitamin K2. Menaquinone is only one form of vitamin K2. Vicki in Illinois * All posts for product information must include the applicable country * Archives are at: Http://Listserv.icors.org/SCRIPTS/WA-ICORS.EXE?LIST=CELIAC