some it's a wild west. but unironically vit d supplementation in winter is a good objectively scientifically proven thing. you can eat it via food but i simply do not eat any foods with vit d.  i started zinc in corona and my morning wood returned i'm 39 so thats more an old man thing. i did 15~30 mg depending on day really. i'm too lazy to buy the rest.  thats the thing i don't think most people realize they're deficient. i think everyone(average adult) in our society as in modern society is vit d deficient, potasium defficent (high blood pressure) there basically no processed foods with potasium because of regulations, and probably zinc deficient.
Croatia