While pharmaceuticals are considered unsafe until proven safe, OTC ‘supplements’ are considered safe for use until proven not so. Do you know anyone who does not take supplements? Today, supplements sales amount to a multi-billion-dollar industry. Essentially, this industry has managed to go unregulated.
There is no entity overseeing, setting standards of purity or handling, as the FDA does for pharmaceuticals. So no one knows what standards for safety and efficacy, supplements meet. Under the Dietary Supplement Health and Education Act of 1994 (DSHEA), supplements such as dietary supplements were placed in the same category as food, which allowed supplement manufacturers to play by a very different set of rules. Please use sites such as consumerLab.com to review available and tested for accuracy supplements. There is a minimal annual fee, but I think it has been well worth it for my personal use.
FYI: Utah is known as the silicon valley of the supplement industry.