I used to take d3: 300iu+vitamin k2 45ug and was feeling good at the late summer until mid autumn. Then i suddenly felt depressed,out of energy and had a hard time losing weight. A few weeks into november i started to get sleep apnea, so I tried without the vitamin d3 cuz i thought i got "too much". It was even worse. Now i had insomnia instead. I read all about this you need 60-80ng/ml for a normal sleep pattern. So i upped the dose right away to 9000iU and could feel it right away the first day! I slept through the whole night, and i just knew this was it. I usually had a big belly during autumn and winter time, always wondered why. Even though i exercise 4times a week intensively = bodybuilding. But always had that protruding gut. I thought i had some problems with the thyroid but it went away right after i upped my dose to 10000IU. The big problem is that if you take k2 like i did at first. K2 can be beneficial but you need sufficient amounts of d3 levels in your body. If not, k2 needs Calcium and Vitamin D to work properly. It's antagonist will be affected as well. I got headaches= signs of magnesium deficiency. So i recommend that you do not supplement with k2 if you're vitamin d and/or magnesium deficient. When you're further in your healing process you can supplement with k2 also if you'd like. But you can always get that vitamin k easier than d3 in the diet, also your gut produces abit of k2 from vitamin k foods. Got these recommendations from Vitamin D Council. Great site! Vitamin d3 deficient? Winter time: 5000-7000ie/daily. Winter time and levels below 30 ng/ml? = Supply with 10 000-15 000 IU/daily for 2-3weeks. Then check your vitamin d levels. Summer time= Sun exposure + 1-5000IE for 2-3weeks. Then check your vitamin d levels.