I tolerate Vitamin D supplements, but can't tell that I'm taking them. I did take the prescription level once for about two years before I finally tipped the balance to test as negative for deficiency. 5000 IU's once a week was the prescription. What the doctor didn't get told is that I started to take it twice a week at the end of that period to see if that would get me out of the really low test range (I think I was averaging 4 - 9 and the goal was 19). Which btw - no impact on symptoms even when I was at 19 (I had hopes, which is why I increased the dosing). Part of me keeps coming back to some of the stuff I'm reading on PR about the test levels. I truly believe that 90% of all the 'deficiency' tests are scaled too low. I think it's the 'proven range' that will definitely have a serious negative impact on your life that gets the 'cut off'. And I think that there is almost always a higher 'optimal' range that leads towards a healthier life free of some of the symptoms. So, of course, once I hit 19 I was told I couldn't have the prescription any longer - because I no longer needed it (sigh). Next time I tested? I was low again (big surprise face here... really? You mean the medicine that got me level that got taken away meant I wasn't level any more? Geez). I just started the D3 drops, so we'll see if there is any benefit to going that direction instead of the gel pill form. If you've noticed my signature - you see I also have tons of MTHFR genes and there are other Detox genes I don't think I remembered to include as well... so I'm thinking it comes down to getting all of the methylation and detox going as well as supporting my D3 processes that will help me in the end. /side track rant/ And, yes. I've been told by multiple doctors that I just needed to try a new form of magnesium. Or, that the quality must not have been good enough. Ummm... pretty sure ALL magnesium supplements I've ever seen list diarrhea as a potential side effect. After two doses (one per day) I get explosive diarrhea. EVERY TIME. I stop it, it goes away. I take it again, it comes back. And yet, I can explain that to the next doctor and they'll suggest, "Oh, but try this one, you should be fine on it.". The last one? Was upset with me after they made me try some and then after I did try it and didn't tolerate it.... was upset with me. Like I chose to have the bad experience. I told her that I didn't think I could tolerate it and she just didn't believe me. Of course, she was also irritated that by just adding basic nutrition that my symptoms would be dramatically improved within a month. I think that the problem is that her assumption was that I must be eating like a teenager before she started to treat me. And when there wasn't any improvement then I automatically must have been doing something wrong. As opposed to the reality of I was already eating fairly healthy foods and improving my diet slightly would be unlikely to make a major impact immediately.