There are only two forms, the plant/mushroom form (D2) and animal (D3) form.
As with anything fat-soluble it's wise to take it as part of a meal that includes plenty of fat.
The problem with most studies is, surely in part because of this unfounded fear, they are underdosed. I don't have anything on hand, but I know there are clinics supervising megadose vitamin D protocols all over the world, but mostly in Germany and Latin America, that I'm aware of.
As with anything fat-soluble it's wise to take it as part of a meal that includes plenty of fat.
The problem with most studies is, surely in part because of this unfounded fear, they are underdosed. I don't have anything on hand, but I know there are clinics supervising megadose vitamin D protocols all over the world, but mostly in Germany and Latin America, that I'm aware of.