Without getting into the specifics of weather particular substances have any meaningful effect vs placebo, part of the issue was that there’s no guarantee that there is even the thing on the label inside the pills or that their formulated in a way that actually makes them available to the body. For instance this study in magnesium supplementation shows a 20-90% absorption based on brand.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6683096/#!po=0....