You mean the rule that’s basically “Anything goes” as long as you reproduce the magic incantation in tiny print at the end:
“This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.”
Linking to a huge list of supplement guidelines, most of which cover labeling of nutrient content is not helpful. I did try to dig in, however, and found this:
> A qualified health claim is supported by less scientific evidence than an authorized health claim. FDA requires that qualified claims be accompanied by a disclaimer that explains the level of the scientific evidence supporting the relationship.
> Unlike authorized health claims, FDA does not issue regulations for qualified health claims.
That does seem to indicate supplement manufacturers have broad latitude to make claims provided they are disclosed as such.
Literally nothing you posted changes the fact that bogus supplements are constantly marketed with carefully-worded health claims (not "disease"! We didn't say "treat"! We didn't say "disease"! These pills just improve your 'gut health' and 'increase endurance'!), with the magic disclaimer at the end.
It may not be the FDA's fault that their authority can be so easily evaded, but it doesn't change the fact that the FDA is a joke.
“This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.”