Vitamin d supplementation studies are a lot more ambiguous than this though. And this also matches my "feel". Getting sun makes me feel good in a way that vit

Vitamin d supplementation studies are a lot more ambiguous than this though. And this also matches my "feel". Getting sun makes me feel good in a way that vitamin D supplementation never does. I was once at a dinner and sitting at the table with the head of the Office of Dietary Supplements for the US government and asked him this question- "How should I get vitamin D and how much should I take?" He answered quite quickly "Get it from sunlight." Your skin autoregulates how much vitamin D is made this way. "The health effects of vitamin D supplementation: evidence from human studies" https://www.nature.com/articles/s41574-021-00593-z https://www.nature.com/articles/s41574-021-00593-z I do think the question is complicated by the fact that humans have wildly different skin tones. What is applicable for skin types that are very pale is quite different than darker skin tones. This question has been complicated even more by recent migration of humans into zones their skin was never meant to be exposed to. It feels like the dermatologists all made their guidelines based on people with porcelain skin that live at the equator. The truth is more complicated than that, people with darker skin develop low vitamin D status follwing those guidelines. Humans love to have blanket rules they can follow without regard to extenuating circumstances like different skin tones, but that isn't reality.