There's evidently a debate whether D2 is as effective as taking D3, so taking D3 seems to be be preferred now.

Even though Phoenix has abundant sunshine, I don't stay outdoors a lot, and my doc said that the body doesn't always convert sunshine to D as it should, hence the need for a supplement. My liver results came back excellent by the way, I don't drink or take much medication other than lisinipril and synthroid...and probably too much ibuprofen, though my liver seems to tolerate it well. I'm cautiously hopeful that the D3 supplement may help ease some of my daily aches and thence help me reduce my ibuprofen use.