The Food and Drug Administration (FDA) does not evaluate dietary supplements for safety or effectiveness before they are marketed, which is why the assertion in the answer choice is accurate. Instead, it is the manufacturer’s responsibility to ensure that the dietary supplements they produce are safe and labeled in accordance with regulations.
The FDA's role comes into play after supplements are marketed. If a dietary supplement poses a risk to consumers or is found to contain harmful ingredients, the FDA may take action, but this occurs post-market rather than during the approval process. This means that stringent pre-market evaluation like that of prescription drugs is not applicable to dietary supplements.
In addition, dietary supplements must adhere to specific labeling requirements to ensure they do not mislead consumers, but these are distinct from being evaluated pre-market by the FDA. This autonomy given to dietary supplement manufacturers significantly differs from pharmaceuticals, where approval and rigorous testing are mandatory.
In summary, the correct answer highlights the FDA's lack of pre-market review of dietary supplements, which is a fundamental aspect of how these products are regulated in the United States.