I take my vitamin D3 along with my magnesium. There’s a reason for that you can find it somewhere online. I just don’t know where it is right now. But since I take magnesium at night, I then take the vitamin D3 at night with magnesium rather than during the day. Either way, I’m usually indoors and don’t see the sun and we don’t have that much sun where I live so hopefully it does what it’s supposed to do.