The supplement manufacturers currently have the advantage - their products don't have to be tested for their safety, quality, effectiveness, or appropriate dosage. Many times, what the manufacturer claims is in the product is not actually present in the quantities labeled. Manufacturers do not have to fund studies to prove the effectiveness, side effects, or appropriate dosage of these products as manufacturers of medications do. Since studies can cost millions of dollars, and studies on nutritional supplements are not legally required, most manufacturers, for financial reasons, choose not to do studies. Independent organizations, not product manufacturers with a vested interest in the product, should conduct research on a product, in order for research to be valid.
Many manufacturers rely on anecdotes from users who claim the product works.
Anecdotes are not valid research. The manufacturers fail to tell you about any negative customer testimonials associated with the product or any potential side effects. They also fail to research the reason behind how the product works if it does appear to work or makes you feel better many times the product working is due to significant pharmacological and physiological actions in the body which produce terrible long-term side effects. Natural does not necessarily equal safe and harmless. You can't tell if one brand is superior to another unless studies are done to compare each product's effectiveness.