Vitamin D3 is a [scam](https://unbekoming.substack.com/p/the-vitamin-d-paradox-what-they-dont). Vitamin D is a theoretical hormone. It is theorized that our bodies produce vitamin D in response to sunlight exposure. We have never isolated vitamin D in the human body, or any animal body. We created a chemical (cholecalciferol) that we believe has the same effect as this theorized hormone and gave it a name. When you get your vitamin D levels checked they are measuring something your body creates from cholecalciferol, not your actual vitamin D levels. There is no way to measure vitamin D because, again, it’s only theoretical. Cholecalciferol has been shown to help with some acute ailments though; like viral infections, cancer, and heart disease. I treat it like a medication. If you want the positive effects of sunlight go outside.