A Proposal for Explaining Progression from Light/Moderate to Severe Chronic Fatigue, 2020, Höck

Can't say I've noticed any difference when my vitamin D levels have been lower than they are now (last I checked they were 80 nmol/L, I do want them >75 nmol/L but if there is any benefit to that it is only present in certain circumstances so it might not matter).

If it is sunshine that's the magic ingredient, it can have other effects on the body than stimulating vit D synthesis. Personally I feel worse in the winter than in the summer, but there could be so many reasons why. That we don't have sun at all for a few months might play into it, but I grew up with sunless winters and it never bothered me before. Winter used to be my favorite time of year

 

I'm a bit annoyed that the omega 3 supplement I'm taking has increased the vitamin D dosage to 40 mcg. I haven't had any problems with hypercalcemia but like you others might. I really like the supplement for other reason, but whyyy. More is not always better. Although for most people vitamin D supplementation at that level is generally safe, and some take much, much higher doses without ill effect.