It is better to take Vitamin D on a daily basis. Having said that if you missed for example Wednesday’s dose, then I would double up on Thursday’s. Also for example if you said I could never remember taking it daily and therefore if I cannot take it once a week, then I will not take any. Then far better to do the once a week then none at all!
We have just started taking 10,000 IUs daily in our house as we are all decificient and nobody can handle that amount. We have severe headaches and body cramps that indicate a magnesium deficiency. So we began 500 mg of Mag Citrate. That helps, but the D3 still makes us all wired as if we had many cups of coffee! I have taken D3 in the past and noticed that 6,000 daily (plus the 800 IU from multivitamin) did not wire me up. I would like to go higher than that but it seems none of us can tolerate it.
I am not a scientist or doctor, only a member. So I can only speculate and make suggestions. Even though you would like to take more, perhaps genetically you simply do not need more then the 6000-7000iu. Perhaps you really need to square away the magnesium deficiency before even trying higher amounts. Sometimes I have recommended taking magnesium for a week or two before even trying the Vitamin D. You can try taking even more magnesium if you want to. Worse case scenario is that you will get “loose bowels” and then you have to cut back on the amount you are taking.