mpe is right, if you supplement D3 you should also use K2 and vitamin A, for example in the following combination:
- 15.000 IU - 30.000 IU D3: depending on what is needed to get your levels up, start with 15.000 IU and test after a few weeks
- 50.000 IU - 100.000 IU Vitamin A: you should use the 9-cis-retinol form, for example from cod liver oil. Intake depending on your D3 intake
But you don´t necessarily have to take supplements. A diet rich in liver or cod liver oil, carrots, meat, eggs and sauerkraut or natto will do the trick for those three. A, D and K are some of the few nutrients you don´t necessarily have to supplement in order to get adequate levels.
To boost your D3 additionally you should go out into the sun between 11am and 2pm, depending on your skin color. Test your tolerance by going out into direct sun for 15 minutes with only minimal clothing. Increase by 15 minutes every two days until you notice a slight coloring. Then decrease this level by 5-10 minutes.
You can increase your tolerance with a mix of natural carotinoids.
If you are taking statins you should choose the supplemental approach though.