Most supplements do not contain what they state are in the bottle, and most are contaminated with heavy metals:
https://pmc.ncbi.nlm.nih.gov/articles/PMC7606431/Even massively popular and common things like protein powders are contaminated:
https://www.consumerreports.org/lead/protein-powders-and-shakes-contain-high-levels-of-lead-a4206364640/Anything that is powdered or in oil form are subject to being cut with various substances for increased profit margins:
https://pmc.ncbi.nlm.nih.gov/articles/PMC10570429/There are endless amounts of studies that look into this — as best as possible, avoid supplements. Get your nutrients from the foods you are suppose to be eating, stop the pizza and refined products, and start eating single ingredient foods in the most whole form possible. Instead of white bread, eat brown rice; instead of protein bars, eat some lentils. This idea is simple, and best of all: cheap.
This is the one area in life where the rich and good fortuned have no advantage over you, in fact they are likely eating very unhealthy themselves despite all their wealth and resources. There are specific diets that are best, but your first and most important step of all is to just begin to eat actual food; single ingredient food, not products, not fast food, not frozen dinners, not packaged goods, not supplements, not oils, not powders, but actual food.