That's true. Asking Lookism about health is much wiser than doing research in scientific articles.
But sarcasm aside, Vitamin D3 is a seco-steroid hormone which has an impact on pretty much everything just like testosterone, cortisol or growth hormone. D3 affects the epigenetic regulation of around 3,000 genes. So if your D3 levels are low, YOU are not functioning properly.
This shows how expression of a few hundred genes changed in participants whose D3 levels just went up slightly.