https://www.bbc.com/future/article/20161208-why-vitamin-supp...
https://www.forbes.com/sites/stevensalzberg/2022/08/01/stop-...
Obviously, some things work for at least a subset of people. I admit it is hard to distinguish real effects from placebo, but stuff like... creatine, which someone mentioned earlier do work.
Since supplements aren't made like pharmaceuticals, this can be a pretty big problem.
Most of the vitamin supplements are cheap to make, there's really no reason for the manufacturer to risk it with adulterated product.
https://www.usada.org/spirit-of-sport/how-to-reduce-your-ris...
> An athlete should never consider any dietary supplement to be 100% safe. No third-party testing company can test for every possible prohibited substance. The NSF Certified for Sport program reduces, but does not eliminate, risk for athletes. It is still up to each athlete to determine whether they want to take the risk of using dietary supplements and USADA does not approve or evaluate dietary supplement products.
It also seems focused on illegal substances, not the purity of the product.
Inverse link to covid mortality: https://pubmed.ncbi.nlm.nih.gov/33260798/ Inverse link to covid mortality: https://pubmed.ncbi.nlm.nih.gov/34684596/ Inverse link to depression in adults: https://pubmed.ncbi.nlm.nih.gov/30470577/
and the best YouTube source of information during this weird pandemia discussing Vitamin D safety: https://www.youtube.com/watch?v=MbUm5FyrHRk
I understand that something being "linked" to something is not a concrete recommendation to take a supplement, but the risks are very low, and the benefit is very high in my opinion, based on this research.
2nd top comment: don't take anything
Wish I knew the right answer