According to her sulfated vitamin d behaves somewhat differently from the unsulfated sort, so this might explain why sunlight gives me almost all of the benefits of oral vitamin D without any of the side effects.
If a person has a bad reaction from oral vitamin D and this is due to overly high levels of calcitriol being made, then the same problem should exist with respect to sunlight, assuming approximately equivalent “dosing” of each (the 25-hydroxyvitamin D3 levels should be a good indicator for equivalent dosing).
Or is your bad reaction to oral vitamin D not associated with a high calcitriol level?
What about you @MeSci? Do you have any testing for calcitriol during times when oral vitamin D3 made you feel worse?
If some people feel worse from oral vitamin D but are fine with sunlight that makes me think there may be more than one type of problem going on - one that involves high calcitriol and one that doesn't - because I (and others) feel worse with both oral vitamin D (any kind, D3 and D2) and sunlight, and with each my calcitriol levels are found to be high with testing while 25-hydroxyvitamin D3 is low. (So I only supplement 500 iu of vitamin D3 per day to keep calcitriol in the mid-upper range.)