medscape.com/viewarticle/98...
Medscape article on the recent large trials of vitamin D supplementation concluded there is no evidence that supplements help most health issues unless you are in a compromised group ie care home resident or very immune compromised such as Chrohns disease, but there is some evidence supplements may be helpful for serious rheumatoid arthritis and some cancer. If you want to take some as insurance, 1000-2000 iu is enough and a safe level. The results on a big Covid trial are not out yet.